Erectile dysfunction (ED) medications are therapeutically effective and associated with satisfaction. Medicare Part D included ED medications on the formulary during 2006 and inadvertently in 2007-2008.To characterize phosphodiesterase-5 inhibitor (PDE-5) medication use among veterans who were dually eligible for Veterans Affairs (VA) and Medicare Part D benefits.Veterans aged > 66 years who received PDE-5 inhibitors between 2005 and 2009 were included. Veterans were categorized by PDE-5 inhibitor claims: VA-only, Part D-only, or dual users of VA and Part D-reimbursed pharmacies. T-tests and chi-square tests were applied as appropriate.From 2005 to 2009, the majority (85.2%) of veterans used VA benefits exclusively for their PDE-5 inhibitors; 11.4% used Medicare Part D exclusively; and 3.4% were dual users. The Part D-only group was older, more frequently not black, had a VA copay, and had a higher income (P < 0.03). The VA group was more likely to have comorbidities, smoke, and have a history of substance abuse (P < 0.001). With the inception of Medicare Part D in 2006, the number of patients filling prescriptions for PDE-5 inhibitors (-68%) and total number of PDE-5 inhibitor 30-day equivalents dispensed (-86.7%) from the VA decreased. Part D prescriptions increased through 2006 (full coverage period) and 2007  and decreased in 2008. While Part D accounted for only 10% of PDE-5 inhibitor 30-day equivalents, it equaled 29.2% of dispensed tablets. In October 2007, VA PDE-5 inhibitor use returned to 2005 levels.Implementation of Medicare Part D reduced VA PDE-5 inhibitor acquisition. However, after removal of PDE-5 inhibitors from the Part D formulary, use of VA pharmacies for PDE-5 inhibitors resumed. Medication policies outside the VA can affect medication use. Veterans with access to non-VA health care may obtain medications from the private sector because of VA restrictions. This may be especially true for nonformulary and lifestyle medications. What is already known about this subjectMedications used for the treatment of erectile dysfunction (ED) are effective for most patients and are well tolerated.While ED medications are not included on the Medicare Part D formulary, veterans have access to these medications on the Veterans Affairs (VA) formulary.What this study addsDuring the period when PDE-5 inhibitors were allowed on the Medicare Part D formulary, PDE-5 inhibitor prescriptions from VA pharmacies decreased, while PDE-5 inhibitor fills from Medicare-reimbursed pharmacies increased. However, this trend reversed after PDE-5 inhibitors were removed from the Part D formulary.VA formulary restrictions can increase the likelihood that veterans who have access to non-VA health care obtain medications from the private sector. Since use of non-VA pharmacies may be unknown to VA providers, these veterans may be at a higher risk of adverse events or drug interactions. This is especially a concern for lifestyle drugs, such as those used for ED.1 The prevalence of ED increases with advancing age and chronic conditions.1 In 1998, sildenafil, the first oral phosphodiesterase-5 inhibitor (PDE-5) was approved, and subsequently in 2003, vardenafil and tadalafil were approved.2 In ED treatment guidelines, the oral PDE-5 inhibitors are considered first-line therapy for ED.3 Sildenafil was added to the Veterans Affairs (VA) National Formulary in 2001.4 In the Veterans Health Administration System (VHA), the use of PDE-5 inhibitors was estimated to be 105.2 patients per 1,000 male veterans during the fiscal years 2004 to 2005.5 In 2006, vardenafil was added to the VA National Formulary.6 Veterans who use PDE-5 inhibitors for ED are limited to 4 doses per month through VA pharmacy benefits .Erectile dysfunction (ED) is defined as “the inability to achieve or maintain an erection sufficient for satisfactory sexual performance.“7 Any medication that meets the definition of a Part D drug is required by MMA to be covered by the Part D program. Originally, ED drugs were covered under the Part D benefit; however, Congress eventually amended the MMA to exclude ED drugs from required coverage. This new classification began on January 1, 2007, and ED drugs used for the treatment of sexual dysfunction or ED did not meet the definition of a Part D drug. An audit conducted by the Office of the Inspector General from November 2009 to September 2010 revealed that some ED medications were mistakenly covered during 2007 and 2008 because the Medicare Drug Data Processing System did not use a complete list of excluded medications.8 Over the 2-year span, the Centers for Medicare & Medicaid Services mistakenly covered $3,107,220 in gross drug costs for ED drugs, with the majority (99.4%) for PDE-5 inhibitors.8 The ED medications to be excluded were updated accordingly and the revised formulary was implemented in 2009.8On January 1, 2006, the Medicare Prescription Drug, Improvement, and Modernization Act (MMA) established coverage for prescription medications through the Medicare Prescription Drug Benefit (Medicare Part D).Although data exist for the use of PDE-5 inhibitors at the population level, limited information exists on the use of PDE-5 inhibitors by veterans who are dually using health care by the VA and the private sector. In addition, no information is available on the effect of health policy changes on the use of lifestyle drugs, such as PDE-5 inhibitors. Thus, the objective of this study was to characterize the use of prescription PDE-5 inhibitors by veterans from 2005 to 2009. Particularly, the effect of Part D pharmacy benefits on PDE-5 inhibitor prescriptions was evaluated to determine if Part D coverage diverted the number of PDE-5 inhibitor prescriptions filled at VA pharmacies or if veterans received PDE-5 inhibitors from both VA and Medicare sources.9 In brief, starting with a random 10% sample of male veterans, those who used VA health care, who were presumed alive through December 2007, were aged 66 years or older, and received at least 1 prescription for a PDE-5 inhibitor between January 1, 2005, and December 31, 2009, were included in this retrospective cohort study. The PDE-5 inhibitors that were included in the analysis were sildenafil, tadalafil, and vardenafil. Female veterans and transgender veterans  were excluded. Secondary to chronic use of PDE-5 inhibitors for pulmonary hypertension , veterans with a pulmonary hypertension diagnosis (ICD-9-CM code 416.0) were also excluded. Veterans were categorized into 3 groups based on where claims were submitted for a PDE-5 inhibitor: VA only, Medicare Part D only, and dual users of VA and Medicare Part D. Demographic data were evaluated during the 2006 calendar year.This was a retrospective cohort study, and detailed methods are described elsewhere.10 Copayment status was determined through the veterans’ priority categories, which were established to manage access to VA care in relation to the VA’s resources based on disability and income. Veterans in priority category 1 do not pay any copayments; veterans in categories 2-6 pay copayments for nonservice-connected medications; and veterans in priority categories 7-8 have copayments for all VA medications. Socioeconomic status of veterans’ geographic areas by ZIP code  was obtained from census data. Rural/urban status was based on rural urban community area codes also derived from ZIP codes.Demographic information for the study population was obtained from the VA Medical SAS Inpatient and Outpatient Datasets and the VA Enrollment file.P value of < 0.05 was considered statistically significant. The study was approved by the Edward Hines Jr. VA Hospital Institutional Review Board.Prescription claims for PDE-5 inhibitors from VA-and Medicare Part D-reimbursed pharmacies were extracted from the VA Managerial Cost Accounting Pharmacy National Data Extract and the Medicare Part D Slim File, respectively, by the generic and brand names. The number of unique patients, total number of tablets, and number of prescriptions were obtained. Thirty-day equivalents were calculated from the prescription quantity and divided by 30 days . Statistical analyses were performed using SAS version 9.3 . Descriptive statistics were used for the baseline characteristics. Differences between groups were compared using either a t-test or chi-square test as appropriate. A In this sample, 24,745 unique veterans who were aged 66 years and older filled a prescription for a PDE-5 inhibitor from to 2009. The majority of these veterans used only VA pharmacies  for their PDE-5 inhibitors over the study period. Only 11.4%  used Medicare Part D-reimbursed pharmacies exclusively, and 3.4% (n = 829) were dual users of VA and Medicare Part D pharmacies. The overall cohort had a mean age of 73.9 (± 4.8) years and was identified primarily as non-Hispanic (95.7%) and nonblack (87.0%). The Medicare Part D group was older, more frequently nonblack, had a VA copay, and lived in areas with higher household incomes . The VA group was more likely to have comorbidities ; smoke; and have a history of substance abuse . Additional baseline characteristics between VA-only users, Medicare Part D-only users, and dual users are presented in From 2005 to 2009, the total number of tablets dispensed was 775,996, with 24.9% of tablets dispensed in 2005 . VardenaAfter implementation of Medicare Part D (2006-2009), the majority (89%) of PDE-5 inhibitor 30-day equivalents were dispensed from VA pharmacies. Interestingly, while Medicare-reimbursed pharmacies accounted for only 10% of PDE-5 inhibitor 30-day equivalents, they accounted for 29.2% of the overall tablets dispensed during this time period. PDE-5 inhibitor prescriptions dispensed by Medicare-reimbursed pharmacies had a greater quantity dispensed as compared with those dispensed by VA pharmacies, with the mean number of prescription dispensed increasing to 71.5 tablets per prescription in 2007 .In 2005, before Medicare Part D implementation, the average number of tablets dispensed monthly was 16,073. The total number of tablets decreased considerably beginning in January 2006, with a decrease in tablets dispensed through VA benefits without a simultaneous increase of tablets dispensed through Medicare-reimbursed pharmacies . In Janu6 Previously, in 2005, sildenafil represented 95.9% of all ED prescriptions dispensed at the VA. The formulary switch to vardenafil as the preferred agent greatly decreased sildenafil use. Therefore, the overall drop in number of prescriptions and unique patients for VA pharmacies may be attributed to this formulary switch. Since PDE-5 inhibitors can be considered lifestyle medications, patients may choose to forgo filling these medications if the barrier to access them is increased. Creation of barriers, such as prescription quantity limits, populations excluded from formulary coverage, and higher copayments, were used with the launch of sildenafil by public and private payers in order to limit the financial impact of the introduction of oral PDE-5 inhibitors.11 Additionally, high rates of discontinuation of PDE-5 inhibitors have been reported, even in men with favorable responses to the medication.16 Surveys assessing patients’ reasons for discontinuation have found a wide variety of factors that affect the use of PDE-5 inhibitors: lack of opportunity for intercourse, psychological issues, ineffectiveness, actual or feared adverse effects, high drug cost, and inconvenience in obtaining the medication.16In this retrospective cohort study, the number of unique patients, prescriptions, 30-day equivalents, and tablets dispensed for PDE-5 inhibitors decreased during the period of dual eligibility for veterans. In addition, there was a small minority of patients who used Medicare Part D benefits for PDE-5 inhibitors. There are several factors that could have influenced the pattern observed in ED medication use during 2005-2009. Vardenafil was added to the VA formulary in and was phased in as the preferred PDE-5 inhibitor in 2007.17 Additionally, the large spike in tablets dispensed by Medicare Part D-reimbursed pharmacies in January 2007 may be secondary to veterans taking advantage of a new benefit cycle and a change in out-of-pocket costs, since Medicare Part D beneficiaries are significantly more likely to reinitiate medications in January.18Veterans may have chosen to use Medicare benefits because the VA had a quantity limit of 4 tablets per month for the PDE-5 inhibitors. For Medicare, 1 tablet per day was acceptable. In addition, the opportunity to access coverage of Medicare Part D for PDE-5 inhibitors was restricted because of the eventual removal of this drug class from the Part D formulary. Therefore, this limited time frame to access both benefits may have affected dispensed prescriptions for PDE-5 inhibitors. Given that there can be a delay in time before new benefits are used, this could have further limited ability by veterans to use the Medicare Part D benefit. Data from the Health and Retirement Study found that, among Medicare enrollees, 12% of the population who enrolled at age 65 waited over 2 years before accessing any benefits covered by Part B.20 Based on the number of tablets dispensed, it does not appear that these alerts had a significant impact on PDE-5 inhibitor use.Safety considerations can also affect the willingness of prescribers or patients to use PDE-5 inhibitors. During this study period, there were 2 safety alerts issued by the U.S. Food and Drug Administration. Alerts regarding risk of nonarteritic anterior ischemic optic neuropathy and risk of sudden hearing loss were released in July 2005 and October 2007, respectively.22 Using VA data from 2004 to 2005, veterans were noted to be older, with 74% of patients receiving PDE-5 inhibitors between the ages of 40 and 69 years, and 23.9% were aged 70 years or older.5 Regarding effects of the recession on medication use, retail prescription sales were compared with state unemployment rates from 2007 to 2010 by Kozman et al. (2012),23 who reported an increase in PDE-5 utilization during the recession with a 3% increase in use per 1% increase in unemployment.It was also noted that the number of prescriptions, 30-day equivalents, and tablets dispensed never fully increased back to the 2005 baseline. Decreased use of PDE-5 inhibitors could be secondary to an aging cohort and potential financial recession effects. Throughout the time period, patients may have had more potential disease or drug interactions as the overall cohort aged, complicating medication management. Additionally, cohort studies of users of sildenafil in a health maintenance organization in Massachusetts and a large managed care organization in the southeastern and western United States reported that approximately 85% of members who obtained sildenafil prescriptions were between the ages of 45 and 74 years and ages 40 and 69 years, respectively.24 Therefore, if medication reconciliation is not performed properly, then veterans may be exposed to a higher risk of adverse events and drug interactions when accessing medications from the private sector.While the descriptive nature of the study precludes an exact determination of the reasoning for veterans changing how they accessed medications during this time period, this study highlights that veterans may access medications outside of the VA health care system, particularly for lifestyle medications and those with formulary restrictions. This action can complicate medication management if veterans do not report use of these medications to VA providers. A previous survey of veterans found that over one third of veterans receiving medications from non-VA pharmacies indicated never discussing their non-VA medications with their VA physicians.8 Finally, secondary to the size of the cohort, a chart review was not performed to detect whether veterans reported outside use of ED medications, which would have helped describe whether VA providers were aware of dual users. Additionally, medical records were only available for patients who were receiving care at the VA .There are several limitations of this study that should be considered. First, diagnosis of pulmonary hypertension was measured by diagnosis codes in the medical record. Therefore, if a patient did not have it as a coded diagnosis, then the inclusion of those patients would inflate the results. This may have affected the data derived from VA sources, especially since VA providers are not reimbursed based on coded diagnoses or treatments. Second, the databases used to capture prescription fills were not be able to capture any prescriptions that were paid for with cash in the private sector. In addition, while an audit revealed that there was a period of accidental coverage under Medicare Part D, it is not known exactly when this was resolved. The audit claimed that by 2009 all national drug codes had been updated, but based on use, this discrepancy appears to have been resolved before 2009.Regardless of these limitations, the results of this study illustrate how changes in pharmacy benefits can affect how patients access and use medications, especially those classified as lifestyle medications. The change in benefits for PDE-5 inhibitors can provide insight into how to manage future changes in prescription medication benefits for a health system. With the changing landscape of the U.S. health care system  that has increased the insured population, policymakers should monitor formulary changes and safety warnings to determine the effect of new policies on medication use. These parameters should specifically include number of patients at risk for events outlined in safety warnings and review of the medication formulary and included National Drug Code numbers. In addition, before a change in the drug formulary and/or a preferred medication, the effect on use and patient adherence should be carefully considered in the outpatient sector.From 2005 to 2009, there was an overall reduction in 30-day equivalents for PDE-5 inhibitors and unique patients. During the period of dual coverage, VA PDE-5 inhibitor use decreased, while Medicare Part D PDE-5 inhibitor use increased. However, after ED medications were removed from the Part D formulary, PDE-5 inhibitor medications dispensed from VA pharmacies resumed. Veterans with access to non-VA health care may obtain medications from the private sector because of VA restrictions, especially for nonformulary and lifestyle medications, which complicates medication management.


The identification of modifiable risk factors is crucial for the prevention and/or reversal of frailty, which is associated with significant morbidity and mortality. Hearing loss affects two-thirds of older adults in the United States (U.S.) and is associated with physical and cognitive decline which may increase frailty risk. We investigated the association of hearing loss and hearing aid use with frailty and pre-frailty in a nationally representative sample of older adults in the U.S.Cross-sectional analysis of the National Health and Aging Trends Study (2021 round). The better-hearing ear pure-tone average (BPTA) at speech-frequencies (0.5–4 kHz) was modeled continuously (per 10 dB) and categorically . Hearing aid use was self-reported. The physical frailty phenotype  was determined based on Fried criteria: unintentional weight loss, exhaustion, low physical activity, weakness, slow walking speed. We used multinomial multivariable regression adjusted for sociodemographic and health characteristics .N = 522), nonusers had greater odds of being frail (OR = 2.54 [1.54–4.18]) and pre-frail (OR = 1.51 [1.05–2.17]) versus robust, and frail versus pre-frail (OR = 1.68 [1.04–2.72]).Among 2,361 participants , 860 (36%) had mild and 864 (37%) had moderate or greater hearing loss. Worse hearing was associated with greater odds of being frail versus robust (OR = 1.20 [1.05–1.38] per 10 dB difference). Categorically, moderate or greater hearing loss was associated with greater odds of being frail (OR = 1.84 [1.01–3.08]) and pre-frail (OR = 1.46 [1.01–2.10]) versus robust. Among 1,724 participants with hearing loss, compared to hearing aid users (In a nationally representative sample of older adults in the U.S., using gold-standard hearing measures and a validated frailty phenotype, hearing loss and lack of hearing aid use was cross-sectionally associated with frailty and pre-frailty. Future longitudinal studies are needed to establish if hearing loss is a risk factor for frailty, which may have significant clinical importance.The online version contains supplementary material available at 10.1186/s12877-023-04465-1. Frailty is a syndrome characterized by diminished physiological reserve causing increased vulnerability to adverse events following stressors and occurs in nearly 1 in 6 older adults in the United States (U.S.) –5. ImporAlmost two-thirds of adults older than 70 years in the U.S. have hearing loss , poorer The National Health and Aging Trends Study (NHATS), a nationally representative study of older adults in the United States, added clinical gold standard audiometric measures in Round 11 (2021) to a test battery that already included a well-characterized frailty measure. Using this data, we tested the null hypothesis that the odds of being frail and pre-frail versus robust and frail versus pre-frail are similar among older adults with and without hearing loss. In secondary analyses, we tested the null hypothesis that among older adults with hearing loss, hearing aid users and nonusers have similar odds of being frail and pre-frail versus robust and frail versus pre-frail.n = 183) and participants missing data on sociodemographic  or health characteristics , and frailty status (n = 50) resulting in a sample of 2,510 participants. We additionally excluded 149 participants with insufficient frailty data to distinguish whether they were pre-frail or frail. Our final analytic sample consisted of 2,361 participants. The NHATS was approved by the Institutional Review Board at the Johns Hopkins Bloomberg School of Public Health. All participants provided informed consent at the time of enrollment in the study. The data used are de-identified and publicly available.The National Health and Aging Trends Study (NHATS) is a nationally representative cohort study of Medicare beneficiaries ages 65 and older in contiguous U.S. since 2011 . Importa2 or unintentionally losing ≥ 10 pounds in the last year. “Exhaustion” was present when participants reported low energy or limited activities due to being easily exhausted. “Low physical activity” was present when participants reported not engaging in vigorous activities or walking for exercise in the last month. “Weakness” was defined by having a grip strength lower than the weight-and-sex specific bottom quintile in the weighted population distribution, based on the maximum over two trials using the dominant hand. “Slow walking speed” was defined as having a gait speed slower than the bottom height-and-sex specific quintile, based on the first of two usual-pace walking trials. The two latter criteria were derived based on the distribution of participants at Round 11 and are detailed in We used the physical frailty phenotype from the Cardiovascular Health Study  to assesPure-tone air-conduction audiometry was done using iPad-based portable audiometers  with sound attenuating Sennheiser DD450 headphones in participants’ homes by trained technicians . The appSociodemographic characteristics included age (years), sex , race/ethnicity , educational attainment , and total income . HealthN = 1,724) and moderate or greater hearing loss , we used the same models to estimate the odds of being frail and pre-frail versus robust (reference) and frail versus pre-frail (reference) by hearing aid use and additionally adjusted for BPTA. We present results as odds ratios (OR) with 95% Confidence Intervals (CI). To obtain representative estimates of US older adults, we accounted for sampling weights ) and 51% greater odds of being pre-frail versus robust (OR = 1.51 [1.05–2.17]) in the fully adjusted model. In addition, nonusers had 68% greater odds of being frail versus pre-frail compared to users (OR = 1.68 [1.04–2.71]).Among participants with mild or greater hearing loss  . Similar among woThe potential role of hearing loss as a risk factor for frailty has broader implications. Currently, the United States Preventive Services Task Force (USPSTF) does not recommend screening for hearing loss in older adults as current evidence is insufficient to assess the balance of harms and benefits . HoweverOur study has several strengths. First, the study sample was more inclusive of older adults in the US compared to previous studies. Second, the newly added pure-tone audiometry measures represent the most used clinical standard. Third, we present novel findings on the association of hearing loss with frailty and pre-frailty as two distinct stages. Limitations include the cross-sectional nature of this study, which prevents us from determining temporality in the association of both hearing loss and hearing aid use with frailty. Second, information on duration of hearing aid use is lacking, limiting our ability to make inferences on the role played. Third, there may be residual unmeasured confounding factors, and this may be particularly significant in the analysis comparing hearing aid users to nonusers. They are distinct groups of individuals that may significantly differ in various aspects including socioeconomic status, healthcare access, and health-seeking behaviors, that we may not have fully accounted for in our analyses. Our findings may also be influenced by survivorship bias. Lastly, excluding participants with insufficient frailty data may have biased our findings. However, in sensitivity analyses including these participants, findings were generally in the same direction.Worse hearing is associated with greater odds of being frail and pre-frail relative to robust in a nationally representative sample of older adults in the U.S. Frailty and pre-frailty are associated with mortality, and identifying and addressing modifiable risk factors is highly important. Future longitudinal research is needed to establish whether hearing loss is a risk factor for frailty.Additional file 1. Supplementary Material.


Hearing is one of the human’s foremost sensors; being able to hear again after suffering from a hearing loss is a great achievement, under all circumstances. However, in the long run, users of present-day hearing aids and cochlear implants are generally only halfway satisfied with what the commercial side offers. We demonstrate here that this is due to the failure of a full integration of these devices into the human physiological circuitry. Important parts of the hearing network that remain unestablished are the efferent connections to the cochlea, which strongly affects the faculty of listening. The latter provides the base for coping with the so-called cocktail party problem, or for a full enjoyment of multi-instrumental musical plays. While nature clearly points at how this could be remedied, to achieve this technologically will require the use of advanced high-precision electrodes and high-precision surgery, as we outline here. Corresponding efforts must be pushed forward by coordinated efforts from the side of science, as the commercial players in the field of hearing aids cannot be expected to have a substantial interest in advancements into this direction. Comparing vision with hearing demonstrates that humans depend as much on auditory as on visual inputs. The compensation of corresponding sensory deficits is, at least in milder cases, much simpler and more successful in the visual domain (glasses and lenses) than in audition.To improve hearing, in extension of the hollow hand, humans used early on animal horns and hallow bones, cf. Whereas weakness in visual focusing can be compensated by optical glasses, a convincing idea of how to cope with corresponding problems in the auditory field seems to be still missing. Present outer-ear artificial hearing aids, as well as inner-ear cochlear implants, have not yet made any serious attempt to restore the active processes that are naturally involved in biological hearing. Digital hearing aids use computer chip technology to convert sound waves into digital signals, which opens the road to complex input signal processing. As most hearing aid users value speech intelligibility as their top priority, speech enhancers, directional microphones, and noise and feedback cancellation come standard with top-of-the-line hearing aids, helping their users to hear speech even in loud and noisy environments. Among the biggest achievements presented, they process auditory signals according to input volume: Soft speech is made audible, while loud speech is kept comfortable. These implemented capabilities are mostly helpful if an intrinsically useful signal  is to be separated from an intrinsically un-useful disturber . As soon as we deal with several signals of potential similar importance , the task becomes a difficult one. Regarding a separation of individual voices from a mixture of voices , as well as regarding the perception of music, the results remain to be rather limited, if compared to the human faculty.The heart of the problem that prohibits hearing aids from making more substantial progress comes from two sides. The most advanced hearing aids boast that, in contrast to competitors, they start to distort by their processing input only above 113 dB SPL “Combining this with a music program that allows as little interaction as possible from the more advanced features in the hearing aid, this higher maximum input level allows musicians to enjoy music even in one of these sophisticated hearing aids” . This hiAs such a sensor can easily be combined with present-day cochlear implant stimulation electrodes, the real challenge to be solved is the cocktail-party problem. In current hearing aid technology, directional microphones are still the top-notch solution for this problem, although in the meantime methods that use the properties of the sources have been demonstrated to work extremely well . In one of these approaches , a speakThe core of this approach was borrowed from how mammalian  hearing is embedded into feedback loops telling the hearing sensor what to listen to. The lack of an appropriate embedding of the hearing aids into the natural sensory network physiology is the main obstacle against arriving at better hearing aids. The cochlea, the mammalian hearing sensor, hosts in the case of humans at birth, on the order of 3,500 inner hair cells and 12,000 outer hair cells. Outer hair cells amplify the shallow fluid surface waves into which the hearing sensor has converted arial sounds after their arrival at the cochlea . UnfortuFrom these and ensuing physiological studies on, the purpose of the eminent innervation of the organ of Corti by means of efferent, almost exclusively inhibitory, connections has remained an open problem. The general belief was that they could play a role in the coding of the sound towards neural signals, cf. . The maiIn our view, these loops, however, foster the biological need of mammals to identify a large spectrum of pre-defined relevant signals as follows. Mathematically, the properties of the outer hair-cells can be represented by dynamical systems that are close to a Hopf bifurcation and act as small-signal amplifiers . Systemss of links being distributed according the typical critical branching network paradigm . Stronger input ( − 50 dB) yields distributions that are typical for supercritical states, whereas upon EMOC activation, the distributions change into a subcritical shape. This reveals that at the most relevant working condition, the system’s information-receiving predisposition is at criticality, whereas listening (implemented by means of EMOCS) is characterized by subcritical states  regulate the Hopf elements’ distances to the bifurcation point, see l states .In the following we demonstrate how EMOCS represent the faculty of listening at the biological level. For this, we reinterpret earlier results  on soundTo achieve separation, the listening process fosters a previously identified subset of amplifiers, disposing amplifiers that are not associated with the desired signal. This process is implemented in biology with the help of information from the brain, mediated by means of EMOCS: Nerves leading from the brain to the cochlea via medial olivocochlear stimulation suppress the efficacy of the targeted cochlea sections by, technically speaking, pushing corresponding Hopf amplifiers further away from their point of bifurcation, cf. TE that has the expression fi denotes the output at section i of the cochlea and the summations extend over the N sections. NACF is the full normalized summary autocorrelation function accounting for all sound characteristics such as e.g., timbre); to measure how strongly a mixture of two input sounds x, y, is biased towards component x, we use the Euclidean distance between the full mixture’s NACF (“NSACF”)and the target signal x’s NACF, divided by the Euclidean distance between the full mixture’s NACF (“NSACF”) and the undesired signal y’s NACF. TE values are between 0 and ∞, where TE = 0 indicates a perfect focus, and a larger TE is a less successful target focus. If one source dominates the mixture, then even before tuning, TE values below unity may emerge. The results displayed in panel b) demonstrate the implemented processes’ efficacy also for time-varying target signals. For fixed target ground signals, panel c) demonstrates how close we get in terms of NACF (red) to the target signals (blue). More information can be extracted by scrutinizing the static case at the level of the signals’ spectra, evaluated at variable signal strengths, which exhibits how EMOCS succeed in suppressing in particular the combination tones among the two signals, see In ω1, ω2 are the characteristic frequencies of the systems and gij captures the coupling from system i to system j; the factor of 1/2 facilitates the generalisation to the N systems used for μ.A second principle that comes to the aid of the EMOCS is the particular efferent innervation within the cochlea, see μ's , reflecOur work opens a perspective towards the development of more adequate cochlear implant hearing aids, responding to the listener’s desire for the selection of particular sounds. This is of importance for the cocktail party problem as well as for listening to many-instrumental music. With the recognition of the physiological network that hearing is embedded in, and with the proper re-embedding of the biomorphic Hopf cochlea  into thi


Hearing-impaired listeners often have difficulty understanding complex sentences. It is not clear if perceptual or cognitive deficits have more impact on reduced language processing abilities, and how a hearing aid might compensate for that.In a prospective study with 5 hearing aid users and 5 normal hearing, age-matched participants, processing of complex sentences was investigated. Audiometric and working memory tests were performed. Subject- and object-initial sentences from the Oldenburg Corpus of Linguistically and audiologically controlled Sentences (OLACS) were presented to the participants during recording of an electroencephalogram (EEG).The perceptual difference between object and subject leading sentences does not lead to processing changes whereas the ambiguity in object leading sentences with feminine or neuter articles evokes a P600 potential. For hearing aid users, this P600 has a longer latency compared to normal hearing subjects.The EEG is a suitable method for investigating differences in complex speech processing for hearing aid users. Longer P600 latencies indicate higher cognitive effort for processing complex sentences in hearing aid users. With increasing age, people often suffer from hearing loss and a decline in cognitive skills , 2. For Sentence comprehension crucially relies on identifying who is doing what to whom. To do this, sentence interpretation require sufficient perceptual and cognitive capabilities. Different sentence types and orders of actors in a sentence can challenge these capabilities. In sentences with two potential actors, German speakers prefer to assign the active role (subject) to the first noun phrase (NP) and the passive role (object) to the second one (for further discussion see ). Thus, Electroencephalography (EEG) is a commonly used tool for investigating language processing. With EEG one can measure event related potentials (ERPs) by presenting visually or acoustically stimulating triggers. There are different acoustically in sentence processing evoked potential types e.g. the P600 component , 10, refStudies with hearing-impaired participants show a slowdown in processing. For object-initial sentences, the responses are delayed , and WenThe aim of the study was to investigate whether and how perceptual deficits in hearing-impaired subjects lead to higher cognitive load during complex sentence processing. To do this, an EEG was recorded while listening to SVO, OVS and ambOVS sentences. We hypothesise that perceptual deficits result in processing difficulties in the hearing-impaired group, which will be reflected by an increased ELAN component at the article of the second noun phrase in OVS sentences. Following reanalysis should be reflected by a following P600. Further, we expect a P600 component in ambiguous OVS sentences due to higher cognitive effort. Psychoacoustic phoneme discrimination tests as well as working memory tests were introduced to assess reasons for changes in processing effort. We infer that perceptual difficulties would result in different cortical potentials for object leading compared to subject leading sentences and cognitive deficits would have a larger impact on the ERPs for the ambiguous sentences. Furthermore, if we can show that EEG with these sentence types is an appropriate method for measuring perceptual differences, further studies with cochlear implant patients who are not suitable for MRI studies, can give insight into speech recognition processes in this patient group.In an exploratory case-control study from December 2021 until November 2022, participants were acquired through personal contact and information on bulletin boards. All data are pseudonymized and just authors can reconstruct by a key list the suitable participants. Inclusion criteria were an age of more than 18 years and German as the mother tongue. The level of education and handedness were determined in an interview. The participants were divided into hearing aid group and an age-matched (± 2 years) normal hearing group.In the normal hearing group a pure-tone hearing threshold  of better than 20 dB was required. The hearing aid group had to be binaurally aided, for at least 6 months, with a stable fitting. There are no restrictions on hearing aid type. The aided 4PTA in open sound field needs to be better than 40 dB and a minimal monosyllable aided word recognition score of 70% at 65 dB SPL was required as well.https://mocacognition.com/) and pass it with normal scores, i.e., at least 26 out of 30 points [To exclude subjects with undetected severe cognitive deficits, all participants had to complete the Montreal Cognitive Assessment  from Written informed consent was obtained from all subjects prior to inclusion in the study. The study protocol is in line with the Declaration of Helsinki and the local ethics conventions .To evaluate the perceptual skills, pure tone audiometry and the German Freiburger Monosyllabic tests as well as the WAKO  , 28 was Cognitive capabilities were determined by a visual span as well as an n-back task . Both tat-test are used to compare the scores of normal hearing participants and hearing aid users for the Freiburger Monosyllabic test, the WAKO, the MoCa, the digit-span ‐ and the 2-back test.For analysis For the following EEG measurement, sentences from the Oldenburg Corpus of Linguistically and Audiologically controlled Sentences  were usAll sentences consisted of two noun phrases (NP1 and NP2) and one verb. In German, overt case-marking appears only in masculine articles. In subject noun phrases, the nominative case (NOM) is marked by “der”, in object noun phrases the accusative (ACC) is marked by “den”. Thus, SVO sentences follow the structure of NP1 (NOM)–Verb–NP2 (ACC), OVS sentences follow the structure NP1 (ACC)–Verb–NP2 (NOM). Therefore, the relevant morphological cue that leads to differences in interpretation is marked in NP1.In contrast, in ambOVS sentences, the first noun phrase is ambiguous due to the feminine or neuter article. Only the second noun phrase provides the crucial information (NOM) necessary for the correct interpretation. However, due to the preferred interpretation of NP1 as a subject, the sentence interpretation needs to be overwritten after disambiguating information in NP2. This is challenging for the working memory.Thirty sound files per sentence type were used. For each sentence, a picture and one picture with exchanged actors exists. These two were presented simultaneously next to each other on a screen, with the participant having to select the correct one. Each sentence was presented twice, once with the correct picture on the right, once on the left side. A total of 180 sentences were presented in pseudorandomised order, divided into 18 blocks of 10 sentences each. The participant had to decide which picture corresponds to the sentence and press a response button .Stimulus presentation was controlled by STIM2 software . Two triggers were set, the first on the beginning of the whole sentence, the second on the article of the NP2. Responses were recorded after sentence presentation.In a sound-isolated room, the participants sat on a comfortable armchair. The visual presentation was realized with a screen at 1 m distance. The acoustic stimuli were presented by loudspeakers at a distance of 1 m with a sound pressure level of 70 dB SPL calibrated using a sound level meter .Stimulation and acquisition were achieved by a system consisting of a stimulation computer with STIM2 software , a StimTrackerDuo , a SynAMPs RT  and an EasyCap . The triggers were sent by STIM2 and the StimTrackerDuo to the recording computer on which the Curry 7 software  recorded the data. Participants responded using the RB-7XX response pad .Sixty-four electrodes were gelled on a standard EEG cap  according to the international 10-20-system , with onThe recorded EEG of all blocks was exported in December 2022 from Curry software  as .ceo (events), .dap (data parameter), .rs3 (geometry) and.dat (data) files and imported to Python with the MNE toolbox (version 1.2). The data were then concatenated to one continuous dataset. A bandpass filter with a Hamming window of 1 to 30 Hz was applied. Subsequently, bad channels were removed when they where without signal or with very noisy signal over a longer time. Beside visual identification in the continuous data and the power spectral density was examined (Welch’s method ) furtherThe two triggers included in the recordings of all sentences were used for final analysis epoching. Therefore, epochs from 0 to 1.5 s were calculated starting at each trigger, including a baseline correction with the data from 1 to 0 s regarding the first trigger of the sentence. All epochs of each trigger and sentence-type were averaged resulting in six ERP curves per subject and recording electrode. For each response of the first sentence part (NP1) the maximal and minimal amplitudes and their corresponding latency at POz were determined; for the second part the maximal ones were determined. Therefore, the minimum and maximum in a range from 0 to 1000 ms were determined, and the corresponding latencies were registered. A grand average was calculated for both participant groups, and plotted.t-test. In case of a significance a topoplot for a time window ± 20 ms around this maximum was generated.In the averages following the second trigger, the significance of the ERP response (maxima) was tested using a Five hearing aid users (mean age (58.2 ± 14.0) years, 3 female, 1 left handed) and five age-matched (± 2 years)) normal hearing participants (mean age (58.2 ± 13.1) years, 4 female, 1 left handed) took part in the study.t(8) = 0.67, p > 0.05). The mean WAKO phoneme test score was (24.4. ± 0.9) for hearing aid users and (24.2 ± 1.1) out of 25 for normal hearing participants (t(8) = -0.31, p > 0.05).The aided PTA4 for the hearing aid group in open sound field was (27 ± 8) dB HL. In the normal hearing control group headphones were used and mean thresholds of (16 ± 10) dB HL for the right ear and (16 ± 11) dB HL for the left ear were measured. The mean WRS for monosyllables at 65 dB SPL was (93 ± 10)% in the hearing aid group and (96 ± 10)% in the control group (p > 0.05). In the digit span test the hearing aid group remembered on average (5.4 ± 0.9) digits and the normal hearing control group (5.4 ± 0.5) digits (t(8) = 0.0, p = 0.5). In the 2-back test, hearing aid users had (94 ± 4) % correct answers and normal hearing control (93 ± 10) %. Both test results were not different between the groups (t(8) = -0.14, p > 0.05). The educational background was also comparable between the groups, since three hearing aid users and two participants in the control group achieved a university degree.The average score in the MOCA test was (28.8 ± 1.1) for hearing aid users and (28.6 ± 1.9) for the control group and thus in the normal range (>26). The scores were not significantly different (t(8) = -0.20, The grand average ERP responses are shown in t(8) = -0.75, p > 0.05). The P600 latencies were (720 ± 54) ms for hearing aid users and significantly shorter for normal hearing listeners (631 ± 27) ms, t(8) = -3.34, p < 0.01).The second row in The main objective of the study was to investigate whether and how perceptual deficits in subjects with hearing impairment lead to a higher cognitive load during complex sentence processing compared to normal hearing listeners. In both groups, no processing difficulties could be detected for OVS sentences compared to SVO sentences. Following these findings, the hypothesis that perceptual deficits in subjects with hearing aids may lead to difficulties in processing the article information cannot be confirmed. Therefore, we conclude that in our group the perceptual deficits were not large enough to have an impact on processing or, in other words, were sufficiently restored by the hearing aids used. The results of the psychoacoustic tests confirm this argument since the achieved scores were comparable. Word and phoneme recognition scores were not different between the groups. The difference in pure-tone hearing thresholds observed obviously did not contribute in a relevant way to a different perception of speech and listening effort.However, despite comparable cognitive capabilities, we could detect differences in processing ambiguous OVS between groups. In both groups, a P600 could be detected at the article of the second noun phrase, which indicates a more difficult analysis of these sentences by activating more cognitive resources. This is in line with other studies showing that an increase in cognitive load is reflected by a P600 component , 17. In This study shows that differences in sentence processing between participants with normal hearing and hearing-impaired participants can be assessed with EEG. The results are consistent with results of eyetracking experiments by Wendt et al. showing that increasing complexity leads to higher processing effort . FurtherThe novelty of this study is that differences in complex sentence processing can also be seen in EEG recordings in hearing aid users. Hearing aid sound processing did not distort the acoustic signal to such an extent that significant differences would have occurred at the perceptual level but we could show in our participants that even with the same cognitive abilities the hearing impaired participants have a higher cognitive effort in processing more complex sentences. Nevertheless, further investigation is needed, especially with cochlear implant users who are not able to participate in functional MRI experiments since the audio processors do not work inside the scanner.In further studies, an extension of sentence material would help to distinguish more detailed between perceptual and cognitive sources of impairment. Gardenpath sentences , e.g., wS1 File(PDF)Click here for additional data file.S2 File(PDF)Click here for additional data file.


Beauveria bassiana is used as a biological insecticide worldwide, wild B. bassiana strains with high pathogenicity in the field play an important role in controlling insect pests via not only screening of highly virulent strains but also natural infection, but the pathogenicity degeneration of wild strains severely affected aforementioned effects. Previous studies have showed that multiple factors contributed to this phenomenon. It has been extensively proved that the mycovirus infection caused hypovirulence of phytopathogenic fungi, which has been used for plant disease biocontrol. However, it remains unknown whether the mycovirus epidemics is a key factor causing hypovirulence of B. bassiana naturally in the field.The entomogenous fungus B. bassiana were collected from different geographic locations in Jilin Province, China, to clarify the epidemic and diversity of the mycoviruses. A mycovirus Beauveria bassiana chrysovirus 2 (BbCV2) we have previously identified was employed to clarify its impact on the pathogenicity of host fungi B. bassiana against the larvae of insect pest Ostrinia furnacalis. The serological analysis was conducted by preparing polyclonal antibody against a BbCV2 coat protein, to determine whether it can dissociate outside the host fungal cells and subsequently infect new hosts. Transcriptome analysis was used to reveal the interactions between viruses and hosts.Wild strains of B. bassiana strains, without obvious genetic differentiation, this virus possessed efficient and stable horizontal and vertical transmission capabilities. The serological results showed that the virus could not only replicate within but also dissociate outside the host cells, and the purified virions could infect B. bassiana by co-incubation. The virus infection causes B. bassiana hypovirulence. Transcriptome analysis revealed decreased expression of genes related to insect epidermis penetration, hypha growth and toxin metabolism in B. bassiana caused by mycovirus infection.We surprisingly found that the mycovirus BbCV2 was prevalent in the field as a core virus in wild Beauveria bassiana infected by hypovirulence-associated mycovirus can spread the virus to new host strains after infecting insects, and cause the virus epidemics in the field. The findings confirmed that mycovirus infection may be an important factor affecting the pathogenicity degradation of B. bassiana in the field.The online version contains supplementary material available at 10.1186/s12985-023-02217-6. Cryphonectria parasitica infected with mycovirus Cryphonectria hypovirus 1 (CHV1) were released in forest, the expansion and spread of chestnut blight were effectively controlled by its epidemic [Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) can directly infect hyphae of the host phytopathogenic fungus Sclerotinia sclerotiorum  in vitro with high efficiency, and direct spraying of the virion on plant leaves can control Sclerotinia disease [Sclerotinia sclerotiorum partitivirus 1 (SsPV1) can inhibit the growth of S. sclerotiorum and significantly decrease host pathogenicity [Mycoviruses can infect phytopathogenic fungi, reducing their pathogenicity toward plants, and providing a means to achieve biological control of plant disease . For exaepidemic . Sclerot disease . Similargenicity , and thegenicity .Beauveria bassiana is an entomogenous fungus that has been used worldwide and developed into a variety of commercial agents for biological control of pest insects in forestry and agriculture [B. bassiana strains, limiting the efficient application of waste resources [iculture –8. Howevesources . The mecesources , 11, theesources , 12, nutesources , 14, moresources , 16. Moresources –19.B. bassiana [B. bassiana. However, a few mycoviruses possess the ability to alter the biological characteristics and virulence of B. bassiana. Kotta and Coutts (2017) found that 16 of 75 strains of B. bassiana from different locations around the world contained mycoviruses, among which mycoviruses Beauveria bassiana polymycovirus 1 (BbPmV-1) and Beauveria bassiana polymycovirus 3 (BbPmV-3) were found to affect pigment deposition, spore production and colony growth of their host fungus by interfering with basic metabolic pathways [B. bassiana populations in the field, even though mycoviruses are able to undergo interspecific, intraspecific and vertical transmission in Beauveria spp. [In recent years, more and more mycoviruses have been isolated and characterised from bassiana –25, mostpathways , 27. Howria spp. . TherefoBeauveria bassiana chrysovirus 2 (BbCV2) that have identified in previous work [Beauveria species [B. bassiana populations in the field; (2) can dissociate outside host fungus cells to infect other strains; and (3) can decrease the pathogenicity of the host B. bassiana strain; we also (4) probed the mechanism through which mycoviruses affect host fungi. The results help to reveal whether mycoviruses are key factors causing B. bassiana hypovirulence in preservation and field applications.To explore these questions, we selected the mycovirus ous work , which i species , and invB. bassiana isolated from Ostrinia furnacatis Guenee muscardine cadavers in corn fields in seven different locations in Jilin Province, China  by heat shock, and sequenced by Sangong Bioengineering Co. Ltd. . The complete sequence of the BbCV2 RdRp gene was obtained by splicing using DNAstar7.1  and DNAMAN version 9 . Modification and splicing of the measured cDNA gene sequence were assessed using Snap Gene 6.0.2  and DNAMAN  9. MEGA11  and DNAsp5  were used to construct a phylogenetic tree of virus BbCV2 in the selected B. bassiana strains collected from different locations in Jilin Province, and the genetic distance was calculated.Three strains of BbCV2-CP and BbPmV-4-CP) of the two viruses were amplified by PCR using specific primers possessing suitable restriction enzyme sites. Construction of recombinant vector, genetic transformation and protein expression were performed as previously described [The dsRNAs of two mycoviruses BbCV2 and a previously reported polymycovirus BbPmV-4  were extescribed . Recombi450 values of polyclonal antibodies (P) and of negative serum wells (N) were determined. Antibody titre tests were conducted three times and average values of P and N were calculated at each dilution. An average P/N ration > 2 was considered positive.Animal immunisation for polyclonal antibody preparation was performed as described previously  using siB. bassiana were cultured on PDA for 10 days, fungal hyphae was scraped for total protein extraction using a Fungal Protein Extraction Kit (SOLARBIO) according to the manufacturer’s instructions, and protein lysis solution was assessed by western blotting as described previously [Virus-infected and virus-free strains of eviously .B. bassiana harbouring virus BbCV2 and BbPmV-4 verified by RT-PCR were used for viruses detection in vitro and in vivo by indirect ELISA. Five randomly selected viruses-free B. bassiana strains verified by RT-PCR served as negative controls, purified CP proteinsof the viruses served as positive control, and double-distilled water served as blank control. Fungal strains were cultured in SDY medium until hyphae formation, the supernatant and pellet were separated by centrifugation, the sediment was washed three times with sterile water to remove culture medium residues, frozen in liquid nitrogen and thawed three times, and lysed by Scientz JY98-IIIDN ultrasonic instrument . Samples were centrifuged, the supernatant was removed, and the pellet was resuspended in phosphate-buffered saline (PBS). These samples and the liquid culture medium used for fungi cultivation were subjected to virus detection by indirect ELISA.Five randomly selected strains of O. furnacatis were infected with conidia of virus-infected strain BbOFDHCV1 and virus-free strain BbOFDH1. Larvae without B. bassiana infection served as blank controls. Ten insects were used in each treatment, and mycelia of strain BbOFDHCV1 cultured in liquid medium served as positive controls. Four days after inoculation, insect bodies were dissected with a sterilised scalpel to obtain epidermis, which was ground in PBS for indirect ELISA detection. Additionally, longitudinally cut insect epidermis from each treatment was mixed with 500 μL 4% paraformaldehyde, fixed for 30 min, centrifuged at 4000 rpm for 15 min to remove paraformaldehyde, rinsed three times in PBS, and blocked with 5% skimmed milk at 37 °C for 1 h. Primary antibody against BbCV2-CP was diluted 1:5000, incubated with samples at 37 °C for 1 h, and secondary antibody, FITC-labelled goat anti-rabbit IgG  at a 1:6000 dilution was incubated at 37 °C in the dark for 1 h. Samples were observed using a Leica DM RBE laser scanning confocal microscope  at a wavelength of 488 nm for hyphae of B. bassiana and 495 nm for hyphae of B. bassiana and virions of BbCV2.Second instar larvae of B. bassiana strain BbOFZK152 was grown on PDA plate for ten days, the mycelia were harvested and ground to powder in the presence of liquid nitrogen. Virus purification was performed according to description of Chiba et al. (2009) [B. bassiana strain BbOFDH1-5-GFP blastspores (108 spores/mL), and incubated in a constant temperature shaker with 120 rpm at 26 °C for 5 days, and centrifuged to collect the mycelium, cleaned and centrifuged for three times with sterile water to ensure the absence of virus particles. The double stranded RNA extraction and RT-PCR were employed for virus validation. The B. bassiana strain BbOFDH1-5-GFP blastspores (108 spores/mL) cultured individually was used as control.To extract viral particles, . (2009) . CarefulBeauveria bassiana strain BbOFZK152 is naturally infected by mycovirus BbCV-2 alone [Ostrinia furnacalis and labelled with the phosphinothricin resistance gene bar and green fluorescence protein (GFP), preserved in the China General Microbiological Culture Collection Center (CGMCC No. 15673). The two strains were cultured on potato dextrose agar (PDA) at 26 °C, and stored on PDA slants at 4 °C in the Jilin Key Laboratory of Agricultural Microbiology. Isogenic strains with and without BbCV2 infection were obtained via the insect coinfection method as described previously [-2 alone , while Beviously . Coinfeceviously  to obtaieviously  and Reveeviously , in whicO. furnacalis was determined using the dip method. Third-instar O. furnacalis larvae were dipped into 2 mL suspensions (107 spores/mL) for 20 s and reared normally on artificial feed. O. furnacalis larvae were divided into seven groups . Each group included three replicates with 20 larvae in each replicate. The number of dead insects was recorded every 24 h, beginning on day 2 and ending on day 8, and survival curves was plotted using GraphPad Prism 8 .Fungal virulence toward 7 conidia/mL) of B. bassiana strains with and without virus infection were added in the same volume (50 mL) of Sabouraud Dextrose Medium with Yeast Extract (SDY) for shaking cultivation at 26 °C for 72 h, then centrifuged at 12,000 rpm for 10 min. The supernatant was removed, dried, and fungal bodies were placed in a drying oven at 40 °C for 2 days. The dry weight of all samples was measured using a 1/10,000 balance . Each fungal strain included six replicates.A 1 mL volume of conidia (1 × 10B. bassiana ARSEF 2860 (NCBI accession number: ADAH00000000) was employed as the reference genome. Clean reads from each library were searched against the B. bassiana genome database using the HISAT2 program [p-values were adjusted to control the false discovery rate (FDR) [2 Ratio (fold change) > 1 at a threshold q-value < 0.05 was obtained (5% FDR). Gene function enrichment analysis is used to categorise the functions of genes using different databases. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analyses of DEGs were performed using the clusterProfiler R package (3.8.1). Significantly enriched functional categories were assigned when the corrected p-value was less than the threshold of 0.05 [Based on the results of virulence against pests, virus-infected strains BbOFDHCV1, BbOFDHCV2 and BbOFDHCV3, as well as virus-free strains BbOFDH1, BbOFDH2 and BbOFDH3 were subjected to transcriptome sequencing. Following incubation at 26 °C for 10 days, total RNA was extracted, and RNA samples were purified and used to construct six libraries. Libraries were sequenced on an Illumina HiSeq 6000 platform at Novogene Bioinformatics Technology Co. Ltd. . Raw data (raw reads) were filtered and checked for sequencing error rate and GC content distribution to obtain clean reads for subsequent analysis. The genome of  program . Gene ex program . Differe program  and p-vate (FDR) . Differe of 0.05 .One-way analysis of variance (ANOVA) was performed using SPSS software version 26.0 . Significant differences were determined with Duncan’s multiple range test.B. bassiana strains. The results of dsRNA extraction morphology showed that B. bassiana strains from all different geographical sites were infected by different dsRNA viruses, and RT-PCR detection showed that BbCV2 was the major virus  model of Tamura Nei (1993) was used to evaluate the base composition of the full-length RdRp gene sequences of all BbCV2 viruses from different collection sites  and three randomly selected virus-free strains  were used for subsequent experiments  for sequencing error rates and GC content distribution, the yielded 40.32 Gb of clean data (clean reads) was used for subsequent analysis. It showed that all libraries had a Q20 value > 97% and Q30 > 93%. The percentage of total sequencing reads successfully matching the genome of Bb2860 exceeded 94%, confirming the quality and accuracy of the data  and chitinases and cytochrome P450 (CYP) metabolizeby B. bassiana contributed to penetration of the insect cuticle [Pr1 and chitinase-related gene BBA_04617, as well as genes encoding CYP52 and other CYPs, including BBA_03806, BBA_06473, BBA_08111 and BBA_09022, were also significantly downregulated following BbCV2 infection. Mitogen-activated protein kinase (MAPK) participates in the process by enhancing the ability to penetrate the insect cuticle from inside to outside [BBA_09043 was significantly downregulated in the BbCV2 infected strain, although its function needs to be clarified.The epicuticle of insects is rich in proteins, chitin and lipids. The expression of some genes encoding functional enzymes that were responsible for the insect cuticle degradation in process of BA_05349 –44, and BA_02581  were sig cuticle . Express outside , here, tB. bassiana forms hyphae within the insect body, which not only cause mechanical damage, but also metabolize toxins to kill the insect. It has been proved that AMAP kinase BBSLT2 encoding gene BBA_03334 could control growth, conidiation, cell wall integrity, and virulence of B. bassiana [Bbpyr (Bb_03937) and Bbthi (Bb_04964) could result in the poor colony growth, fewer hyphae and conidia of B. bassiana [BA_03426, BBA_10003 and BBA_09074 encoding homologs of BCS1 domain-containing proteins were significantly down-regulated following the virus infection.After penetrating the insect epidermis, bassiana , which wbassiana , herein,bassiana , in thisBBA_06613, BBA_03616 and BBA_09856 were significantly downregulated. Nonribosomal peptide synthases (NRPSs) are closely related to the metabolism of microbial toxins and antibiotics. B. bassiana can metabolise various toxins through NRPS pathways, including beauveritin 14, 2-pyridone tenellin, bassianin 25, beauveritin and bassianolide [BBA_04028, BBA_08222 and BBA_03671) were identified in B. bassiana isolated from Plutella xylostella [BBA_09856, BBA_03616, BBA_01841 and BBA_04028) that were significantly downregulated. BBA_04028 encodes BbLaeA, and knockout of BBA_04028 diminished beauvericin and bassiatin metabolism, while overexpression of BbLaeA increased the production of toxins [Polyketide synthases (PKSs) synthesize secondary metabolites such as oosporein that inhibit polyphenol oxidase (PPO) activity, which leads to inhibition of the expression of insect antimicrobial peptides , 53. In ianolide –56. Threlostella . Here, wf toxins .To validate the results obtained in RNA-Seq experiments, four upregulated and six downregulated genes were randomly selected for qRT-PCR validation with specific primers. Relative expression measured by qRT-PCR was consistent with expression levels measured by RNA-seq for all tested genes  had great potential and application prospects for controlling the fungal diseasesouthern blight in a wide variety of crops, which caused by a phytopathogens Sclerotium rolfsii [Fusarium graminearum, the causal agent of fusarium head blight, but also further clarified that virus response 1 (vr1) was a key hypovirulence causing factor of the virus  [Metarhizium majus [B. bassiana hypovirulence. In the present study, we found that mycovirus BbCV2 caused hypovirulence of B. bassiana toward the insect pest O. furnacatis, and decreased biomass.Mycoviruses can not only reduce the pathogenicity of phytopathogenic fungi but also convert host pathogenic fungi into a biocontrol agent , 59. More oryzae . It has e oryzae –63. Guo of crops . Zhong e rolfsii . Borwmaninearum) . Unfortuum majus . HoweverB. bassiana during field usage and strain preservation affect its biocontrol applications. Epidemics of mycoviruses in phytopathogenic fungi provide a biological control opportunity for plant diseases. However, whether mycoviruses that infect entomopathogenic fungi are prevalent in the field and can thereby cause hypovirulence of wild B. bassiana remains unknown. Here, we collected and characterised B. bassiana strains from diseased O. furnacatis in different geographical locations in fields in Jilin Province, China, and discovered that BbCV2 virus infection was widely present in wild B. bassiana strains, with a virus-harbouring rate up to 90%. Furthermore, the virus-harbouring proportion was not correlated with collection site, indicating that the virus is likely to spread naturally within the region. Jia et al. monitored the interannual dynamics and abundance of mycovirus infections in S. sclerotiorum; 24 kinds of mycoviruses classified as members of the local core virus group exhibited persistence and relatively high transmissibility in a single crop field [B. bassiana isolated from O. furnacatis from different sites, and epidemics of this virus may be a key factor responsible for hypovirulence of B. bassiana in the field.Decreased pathogenicity of op field . In the B. bassiana places no significant selection pressure on the virus, suggesting that the virus takes the initiative in interactions between the two.During interactions with host fungi, mycoviruses can mutate, leading to genetic diversity. Viral genetic diversity has important implications for virus persistence, pathogenesis and transmission , and is Lycoriella ingenua, which was regarded as a transmission vector for virus spread, and more importantly, this virus could multiply and transmit vertically within the life cycle of insects [Magnaporthe oryzae, which was detected not only in host cells but also in culture supernatant. Furthermore, abnormal aggregation of mycelia was observed after adding the mycovirus-containing culture supernatant to an uninfected strain of M. oryzae and mycoviral dsRNAs were detectable from the aggregated mycelia [B. bassiana to another two Beauveria species via not only hyphal anastomosis but also insect coinfection [B. bassiana, as well as vertical transmission in the same strain. However, it is not clear whether the virus transmitted through direct fusion of mycelia by coculture on medium and coinfection in insect bodies, or whether virions could be released outside host fungi cells and then infect other strains. Here, we detected the viruses BbCV2 and BbPmV-4 both inside host fungal cells and in the culture medium by indirect-ELISA, the viruses concentration in the supernatant are higher than that of fungal cells, which confirmed that the mycoviruses had the ability to dissociate outside the cells of host fungi, and the virions can also infect B. bassiana blastspores through co-incubation, it was consistent with the research of Urayama et al., in which they found that purified virions could infect host fungi in vitro [B. bassiana population, thereby diminishing the virulence of wild B. bassiana strains in the field. Further research is needed to explore whether the BbCV2 mycovirus can infect insects and multiply in the insect body.Mycoviruses can transmit interspecifically and intraspecifically between host fungi , 74. Liu insects . Urayama mycelia . Our prenfection . In the in vitro . FurtherB. cinerea infected by Botryosphaeria dothidea chrysovirus 1 (BdCV1) and Botryosphaeria dothidea partitivirus 1 (BdPV1) viruses, differential genes between virus-infected and virus-free strains were identified, and DEGs enrichment analysis identified genes related to metabolic processes, cellular processes, catalytic activity, transporter activity, signal transduction and other biological pathways, and subsequent KEGG analysis identified numerous DEGs associated with metabolism, transcription and signal transduction [S. sclerotiorum, 958 mRNAs were affected by the hypovirulent hypovirus2-L, with over 100 genes involved in basic metabolism and sugar and lipid transport [B. bassiana is a complex biological process involving the metabolism of hydrolytic enzymes for epidermis penetration [B. bassiana infected with hypervirulent mycovirus BbPmV-4 showed that virus infection significantly increased the expression levels of some genes related to MAPK (BBA_09022) and cytochrome P450  in B. bassiana [B. bassiana, but this needs to be verified at the protein level though co-immunoprecipitation assays [B. bassiana fungal host in future.In studies on the interaction mechanisms between mycoviruses and host fungi, transcriptome data are important for clarifying the influence of viruses on the main functional genes and pathways of hosts, and transcriptomics is widely used to screen interacting genes. In sduction . In S. sransport . Pathogeetration , the hypetration . In our bassiana . By contbassiana . Hence, n assays , both ofB. bassiana has mainly involved isolation and screening of wild strains collected from the field using biological testing, which is time-consuming and labour-intensive [B. bassiana virulence, and virus detection could be used to exclude hypovirulent virus-infected strains, and to screen strains of wild B. bassiana with high virulence, thereby improving the efficiency of high virulence strain screening. To the best of our knowledge, detection of mycoviruses has mainly been performed using dsRNA and RT-PCR methods, which require complex software and can be used for qualitative but not quantitative testing. Efficient and specific serological techniques have been widely used for quantitative and qualitative detection of animal and plant viruses [In the past, acquisition of high-virulence strains of ntensive , 84. Her viruses , 86, butAdditional file 1: Table S1. Tested strainsAdditional file 2: Table S2. Primers for RdRp gene amplificationAdditional file 3: Table S3. Base content of RdRp gene sequences of BbCV2 virusesAdditional file 4: Table S4. Sequence informationAdditional file 5: Table S5. Efficiency of virus vertical transmission of B. bassiana via subcultureAdditional file 6: Fig. S1. SDS-PAGE analysis of purified recombinant BbPmV-4-CP and BbCV2-CP proteins. (A) Ultrafiltration of recombinant BbPmV-4-CP Protein. Lane 1, recombinant BbPmV-4-CP protein following ultrafiltration. (B) Ultrafiltration of recombinant BbCV2-CP Protein. Lane 1-5, recombinant BbCV2-CP protein following ultrafiltration.Additional file 7: Fig. S2. Determination of the polyclonal antibody titre of BbPmV-4-CP and BbCV2-CP protein. (A) BbPmV-4-CP. (B) BbCV2-CP.Additional file 8: Fig. S3. Detection of BbCV2 and BbPmV-4 virus in and outside host cells by indirect-ELISA. (A) Liquid culture medium of Beauveria bassiana containing virus BbCV2.1, blank control; 2, positive control (BbCV2-CP); 3, negative control (supernatant of virus-free strains); 4, supernatant of BbCV2 virus-harbouring strains; 5, negative control (pellet of virus-free strains); 6, pellet of BbCV2 virus-harbouring strains; (B) Liquid culture medium of Beauveria bassiana containing virus BbPmV-4.1, blank control; 2, positive control (BbPmV-4-CP); 3, negative control (supernatant of virus-free strains); 4, supernatant of BbPmV-4 virus-harbouring strains; 5, negative control (pellet of virus-free strains); 6, pellet of BbPmV-4 virus-harbouring strains. (C) Insect bodies. 1-2, negative control (larvae without B. bassiana infection); 3-4, larvae infected by BbOFDH; 5-6, larvae infected by BbOFDHCV; 7, positive control (BbCV2-CP).Additional file 9: Fig. S4. Detection of BbCV2 virions by indirect-ELISA and dsRNA extraction. (A) Detection of virions in different gradients of sucrose by indirect-ELISA. +, positive control (BbCV2-CP); −, blank control; 20%–50%, different gradients of sucrose; (B) DsRNA of virions in 30% sucrose.Additional file 10: Table S6. Summary of sequencing dataAdditional file 11: Fig. S5. Correlation heatmap of strain samplesAdditional file 12: Fig. S6. qRT-PCR verification of RNA-Seq gene expression levels


The risk of ototoxicity, characterized by hearing impairment, tinnitus, or middle ear inflammation, is elevated in both child and adult cancer survivors who have undergone head-neck or brain radiation, or a combination of the two. To provide optimal care for these cancer survivors and minimize subsequent complications, it is crucial to comprehend the relationship between radiotherapy and ototoxicity.A comprehensive search of databases, including the Cochrane Library, PubMed, Embase, and Web of Science, was conducted from the inception of the knowledge base up until January 2023. The metafor-package was employed to compare ototoxicity rates in individuals receiving radiotherapy. Two independent assessors extracted data and analyzed targets using a random-effects model.2 = 0%). Stereotactic radiotherapy appeared to be a superior option for hearing preservation compared to radiosurgery . Children demonstrated a higher risk of hearing impairment than adults. More than 50% of patients with vestibular neuroadenoma experienced hearing impairment following radiation therapy. A strong association was observed between the average cochlear radiation dose and hearing impairment. Increased cochlear radiation doses may result in a heightened risk of hearing impairment.Out of the 28 randomized controlled trials (RCTs) included in the analysis, 25 were prospective RCTs. Subgroup analysis revealed that mean cochlear radiation dose, primary tumor location, radiotherapy modality, and patient age significantly influenced total hearing impairment. Intensity-modulated radiotherapy was associated with less ototoxicity than 2D conventional radiotherapy (OR, 0.53; 95% CI, 0.47–0.60; P = 0.73; ISeveral risk factors for radiation-induced hearing impairment were identified in this study. High cochlear radiation doses were found to exacerbate the risk of hearing impairment resulting from radiation therapy.The online version contains supplementary material available at 10.1186/s13014-023-02268-7. Ototoxicity, which can manifest as hearing impairment, tinnitus, and/or vertigo, is a recognized adverse effect associated with a group of antitumor therapies, including platinum chemotherapy, radiotherapy, or surgery involving the ear and auditory nerves . HearingRadiation therapy (RT), which can be utilized as a single treatment modality or as an adjuvant treatment before and after surgery, is commonly used to treat patients with a variety of cancers. Patients with locally advanced and inoperable head and neck tumors are usually treated with cisplatin-based chemoradiotherapy. Cisplatin or carboplatin-based chemotherapy drugs are known to cause ototoxicity . WintherDespite the prevalence and severity of ototoxicity following radiotherapy, it has seldom been reported in radiation oncology literature. The correlation between cochlear radiation dose and subsequent morbidity has rarely been documented. The objective of this study is to assess the incidence of various factors that may contribute to radiotherapy-induced ototoxicity.This meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) .Databases, including the Cochrane Library, PubMed, Embase, and Web of Science, were searched from inception until January 2023. Medical Subject Headings (MeSH) and text word combinations were employed to create three subsets of references: the first subset encompassed radiotherapy ; the second subset involved complications related to hearing ; and the third subset pertained to cancer. After an initial screening of titles or abstracts, two independent reviewers  assessed the full text of relevant publications and the reference lists for final inclusion. Additionally, references considered potentially relevant were searched and thoroughly evaluated.Studies were included based on the following criteria: (1) studies that reported hearing impairment in cancer patients due to RT as a first-line treatment; (2) hearing outcomes obtained from pure tone audiograms  conducted before and after treatment; (3) studies providing the number of individuals evaluable for toxicity following radiotherapy and the number of individuals with hearing impairment; (4) studies that clearly defined hearing impairment and offered sufficient irradiation information to quantify the effect; and (5) studies that were randomized controlled trials, excluding one-arm trials. All criteria needed to be met for study inclusion. Exclusion criteria encompassed postoperative studies, single-arm studies, case reports, reviews, meeting minutes or abstracts, articles not published in English, and studies with cisplatin as monotherapy.Two evaluators independently employed standardized forms to extract and summarize the following data: first author, year of publication, study ID, country, cancer type, radiotherapy design, radiotherapy mode, cochlear radiation dose, total number of patients, number of patients for safety analysis, standard version of general terms for adverse events, rate of hearing impairment, and frequency of tinnitus and vertigo symptoms. The standard for general terms of adverse events served as the most commonly used tool to evaluate the type and severity of adverse events in clinical practice, featuring a grading scale and clear definitions.Two reviewers  evaluated the risk of bias based on the original studies, utilizing the Cochrane Collaboration’s tool. Five aspects of adequacy were assessed: random sequence generation, allocation concealment, blinding, outcome assessment, and outcome reporting . Each it2 statistic were utilized to assess statistical heterogeneity [2 exceeded 25%, 50%, or 75%, it indicated low, medium, or high heterogeneity, respectively. If significant heterogeneity was present, a random-effects model was used. A simple analysis of funnel plots offered a useful test for possible bias in meta-analyses [Meta-analysis was performed using R(4.2.1) statistical software (metafor and meta package). Fixed-effect or random-effects models were employed to estimate event rates and their corresponding 95% confidence intervals. Forest plots were constructed to summarize data and incidence for each analysis group. The Cochran Q statistic and the Iogeneity . When I2analyses . OtherwiAfter 5192 duplicates were deleted and filtered by title and abstract, 286 of the 3134 records initially searched were reviewed in full. Due to insufficient data or lack of full text in meta-analysis, we excluded 20 studies. Finally, 28 eligible studies were included, including 25 prospective randomized controlled trial and 3 retrospective randomized controlled trials –14. The The risk of bias was assessed for each included study . All RCTs were combined to compare the ratio of the experimental arm to the control arm, and the heterogeneity was high. Since the experimental design of each included RCT varied, subgroup analyses were performed based on population characteristics, original tumor, radiotherapy modality, and mean cochlear dose to explore potential sources of heterogeneity.The 28 included studies compared the risk of all levels of hearing impairment effects in cancer patients receiving first-line therapy as radiation therapy . The result suggested that Cetuximab combined with radiotherapy resulted in lower hearing impairment than Cisplatin combined with RT.Four trials involved the combination of Cetuximab and RT compared to the combination of Cisplatin and RT Fig. A. Three 2 = 0%). Two studies demonstrated the combination of ART and chemotherapy compared to conventional radiotherapy and chemotherapy .Two trials compared ART with conventional-RT for ototoxicity Fig. B. Pooledapy Fig. C. The re2 = 0%). The advantages of IMRT can be seen in comparison with the hearing impaired population of Conventional-RT     Fig. F. Three 0%) Fig. G.2 = 15%)  . The probability of hearing toxicity in children is higher than in adults.In the summary analysis of hearing impairment by comparing age groups, three studies included children under 18 years of age, and the combined effect value of hearing impairment was 0.95 . The hearing impairment of glioblastoma patients after irradiation was also relatively evident . Radiotherapy-associated hearing impairment in vestibular adenomas was high among all primary tumors included in the literature  . When the cochlear radiation dose was 40-50 Gy, the combined value of total hearing impairment was 28% . When the cochlear radiation dose increased to 50-60 Gy, the probability of total hearing impairment was the highest, at 35%  , and patient age may influence the risk of hearing impairment. IMRT radiotherapy-associated ototoxicity was less common than conventional radiotherapy. Stereotactic radiotherapy appeared to be a better option for hearing protection than radiosurgery. Children are at a higher risk of hearing impairment than adults. Over half of patients with vestibular neuroadenoma experience hearing impairment after radiation therapy. The average cochlear radiation dose is strongly associated with hearing impairment, and the radiation dose to the cochlea must be precisely controlled. To the best of our knowledge, this is the first comprehensive meta-analysis to analyze ototoxic injury caused by radiotherapy.Previous literature has discussed the relationship between ototoxicity and radiotherapy. Theunissen and others conducted a study on sensorineural hearing loss (SNHL) caused by radiotherapy of head and neck tumors, suggesting that factors influencing the risk of SNHL included cochlear radiation dose, population age, and follow-up time . RadiatiDiscussions about the optimal treatment strategy for techniques, prescription dosing, and segmentation are based on the need to prioritize curing the tumor while maintaining an acceptable risk of complications. Pediatric brain and head and neck malignancies requiring dose escalation, as well as adult skull base malignancies, are internationally recognized indications for proton therapy, exhibiting good local control, survival, and acceptable toxicity rates , 47. DueEarly radiation-induced ototoxicity is associated with mucosal edema, inflammation, and scaling of the outer, middle, and inner ear tissues . The outIn this meta-analysis, the influence of age, radiotherapy mode, primary tumor, and mean cochlear dose on ototoxic hearing impairment is discussed. It can be concluded that the dose delivered to the inner ear , radiotherapy technique , tumor type, and the age of the radiotherapy population are closely related to radiation-induced ototoxicity. The primary sites of radiation-induced ototoxicity are the paranasal sinuses, nasal cavity, nasopharynx, and parotid glands . In the In this study, the subgroup analysis of hearing impairment with different radiotherapy techniques was analyzed. From the results, it is evident that the impact of carbon ions on hearing loss is minimal, making it a more reliable choice. Before the advent of IMRT, traditional two-dimensional radiation therapy was used. The response to radiation therapy depends on the sensitivity of tumor cells to radiation. In theory, higher radiation sensitivity leads to better therapeutic effects. However, the damage caused by treatment to the surrounding normal tissues also increases. Heavy particles, such as carbon ions, release energy to centrally explode tumor cells, maximizing the effect of radiotherapy and reducing damage to surrounding healthy tissues. Huang et al. divided 26 pediatric patients receiving medulloblastoma treatment into two groups, receiving conventional radiotherapy or IMRT, respectively. The pure tone audiogram was detected, and hearing function was graded from 0 to 4 according to the toxicity standard of the pediatric oncology group. They concluded that, compared to the traditional RT group, the IMRT group had a lower average decibel hearing threshold at each frequency. The overall incidence of ototoxicity in the IMRT group was low. Thirteen percent of the IMRT group had grade 3 or 4 hearing loss, compared with 64% of the conventional RT group . In the The first-line treatment for radiation ototoxicity is drugs, which can be injected into the ear with a vasoconstrictor . If thisThis study had several limitations. First, there are few RCTs providing average doses of cochlea, making it difficult to analyze the link between doses and ototoxicity on a large scale. Second, potential bias may exist due to differences in tumor stage and underlying disease in the included population. Third, the number of RCTs involved in each radiotherapy technique is small.In this study, randomized controlled trials were analyzed to compare the association of various factors with radiotherapy-related ototoxicity. Radiation design patterns and doses, population characteristics, and tumor characteristics are all intricately linked to ototoxicity. Children treated with RT, particularly those receiving chemotherapy, have a higher risk of hearing impairment; therefore, their cochlear restraint should be lower. To gain a better understanding of hearing toxicity, it is crucial to collect clinician-reported results at baseline and during follow-up, in addition to tests such as audiograms.Additional file 1. Fig.S1. Bias risk assessment chart. Fig.S2. Subgroup Analysis of the Association of RT With Hearing Loss by Cochlear irradiation dose. Fig.S3. Funnel chart of total hearing loss. Fig.S4. Sensitivity analysis of hearing loss.


Here, we present a case of a 15-year-old male with polyradiculoneuropathy, which was diagnosed as chronic inflammatory demyelinating polyneuropathy (CIDP), who was refractory to initial treatment. The patient presented with a one-and-a-half-month history of decreased strength, most notable in the bilateral hip flexors and finger flexors/extensors, and areflexia. Electromyography and nerve conduction studies did not fulfill diagnostic criteria for a demyelinating polyneuropathy; however, the cerebrospinal fluid analysis demonstrated albuminocytologic dissociation and his physical exam was otherwise consistent with the diagnosis. He was treated with IV immunoglobulin (IVIg). He relapsed less than one month later with worsening weakness. Imaging revealed increased cauda equina enhancement when compared to the MRI from the previous admission, and labs were otherwise similar to the initial presentation. He was treated with a second course of IVIg in addition to high-dose IV methylprednisolone. Upon his second discharge, he was transitioned to oral corticosteroids, and at a follow-up visit one month later, he had fully regained his strength and demonstrated normal reflexes. This case highlights the variable nature of CIDP in its initial presentation, its course, and its response to treatment, particularly in young patients. Additionally, we would like to emphasize that this case of CIDP was in the context of chronic malnutrition and significant weight loss, which made the diagnostic picture more complex. Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired, autoimmune condition characterized by demyelination of peripheral nerves resulting in progressive sensory loss and muscle weakness . EpidemiThe differential diagnosis includes Guillain-Barré syndrome (GBS), most commonly the acute inflammatory demyelinating polyneuropathy (AIDP) subtype. CIDP is differentiated from AIDP by a temporal cutoff of four weeks for AIDP and eight weeks for CIDP . BetweenWe would like to present an atypical pediatric case of polyradiculoneuropathy diagnosed as CIDP that occurred in the setting of malnutrition and an unspecified eating disorder that was initially refractory to treatment. This dysimmune neuropathy is only rarely observed in the pediatric population, which makes the diagnosis and treatment choices more challenging.A 15-year-old male without any significant past medical history presented with a one-and-a-half-month history of progressive muscle weakness most pronounced in the distal upper extremities and proximal lower extremities that progressed in severity and led to difficulty walking and falls. He reported a recent 35-pound (15.88 kg) weight loss via voluntary diet restriction over the course of four months prior to presentation. There was no recent viral illness or vaccination and no family history of any neurologic conditions.Upon admission, the neurological exam was notable for diffuse weakness, worst in bilateral hip flexion, finger extension, and finger flexion. No sensory or autonomic disturbances were appreciated. There was no oral muscle involvement and deep tendon reflexes were absent. Laboratories assessing nutritional deficiencies were notable for borderline low folate, with a normal methylmalonic acid level. HIV, syphilis, and hepatitis B and C studies were also negative. Diagnostic studies were significant for magnetic resonance imaging (MRI) of the lumbar spine demonstrating mild enhancement of the cauda equina roots.Nerve conduction studies (NCS) of the right upper extremity were performed, which did not demonstrate any sensory or motor abnormalities in the median or ulnar nerves. Electromyography (EMG) of the right deltoid, triceps brachii, and first dorsal interosseus also was normal. EMG and NCS in the lower extremity, which was clinically weak, demonstrated impersistent F-waves and mildly reduced recruitment activity in the deep peroneal nerve, suggesting neurogenic weakness. There were no other findings to suggest demyelination on this diagnostic testing despite his clinical manifestations. The sural sensory study was also normal. CSF analysis, which can be found in Table Upon the second admission, the neurological exam was significant for weakness that was most pronounced in the distal upper extremities and proximal lower extremities, a pattern similar to when he was discharged. He remained areflexic and his sensory and cranial nerve exams were grossly normal. No involuntary movements were appreciated. Malabsorption labs showed slight abnormalities, which can be seen in Table EMG/NCS of the right upper and lower extremities again showed no clear demyelination, although F-waves remained absent or impersistent, showing increased latency. Amplitude and duration of compound muscle action potential were normal. Conduction velocities and latencies were normal except for slightly prolonged latency in the right peroneal nerve innervating the extensor digitorum brevis. Decreased recruitment was more clearly seen in clinically weak muscles, suggesting neurogenic weakness. MRI of the lumbar spine again showed enhancement of the cauda equina nerve roots, seen from a sagittal view in Figure This case of pediatric CIDP is striking in numerous ways and offers several important clinical reminders. First, the presentation itself was somewhat atypical. The patient’s clinical phenotype and course were consistent with CIDP, although he did not meet any electrodiagnostic criteria. Time to treatment was crucial for this patient and because repeat electrodiagnostic testing would not have otherwise changed management, it was not performed. Overall, CIDP is classically a polyradiculoneuropathy with dysfunction at both the level of the roots and peripheral nerves. Given his distribution of weakness, the lack of sensory deficits on physical exam, and no clear evidence of demyelination of sensory fibers on NCS, the dysfunction is predominantly proximal to the dorsal root ganglion, more specifically at the level of the nerve root. This is further supported by enhancement of the cauda equina seen on MRI with correlation of abnormal CSF findings. Although there is no genetic test for CIDP, certain inherited neuropathies can mimic its presentation and can be tested for  . In consAn inflammatory demyelinating polyneuropathy is considered chronic when the disease has lasted longer than eight weeks and acute when the course has resolved in four weeks or less; a presentation between four and eight weeks is considered subacute. CIDP is differentiated from the acute and subacute presentations by a time course of eight weeks . With reTo diagnose typical CIDP, the following clinical criteria must be met: progressive or relapsing, symmetric, proximal, and distal muscle weakness of upper and lower limbs, and sensory involvement of at least two limbs; development over at least eight weeks; and absent or reduced tendon reflexes in all limbs. All variants apart from pure motor must have sensory involvement. Thus, our patient, given that he had no measurable sensory deficits, may have fallen into the pure motor variant of CIDP. To diagnose pure motor CIDP, the following is required: clinical criteria, motor conduction criteria in two nerves, and normal sensory conduction in four nerves. If possible motor CIDP criteria are met and there is also a presence of at least two supportive criteria, pure motor CIDP can be diagnosed. To diagnose possible CIDP, motor conduction criteria in only one nerve is required in addition to the other motor CIDP criteria. This patient met the clinical criteria for pure motor CIDP, had two supportive criteria, with CSF findings and MRI, and had normal sensory conduction in the three nerves that were tested. Motor conduction criteria can be met in several ways with electrodiagnostic testing; however, this presentation was atypical even for the pure motor variant; there was no clear evidence of significant demyelination and no peripheral nerve slowing in the EMG/NCS studies. This could be due to his disease predominantly affecting the nerve roots, thus not allowing us to detect sensory abnormalities. With respect to imaging, there is currently no evidence to support the use of MRI in pediatric patients due to a lack of systematic studies, although it can be used to support the diagnosis of CIDP in adult patients who fulfill criteria for possible CIDP but not definite CIDP. Typical MRI findings supportive of CIDP are enlargement and/or increased signal intensity of nerve roots. MRI of this patient did show enhancement of the cauda equina roots, which is supportive of the diagnosis of CIDP but not diagnostic. In general, the role of neuroimaging in the diagnosis and treatment management of CIDP is an area that continues to be studied . PatientSecond, the patient initially showed improvement with the first IVIg treatment but ultimately had a re-exacerbation of symptoms. IVIg is typically the first line for CIDP, including pure motor variants. Corticosteroids can also be used as first-line treatment, and if neither works, other treatment options like plasma exchange may be considered . Other aIn this case, the use of corticosteroids provided an additional treatment option that the patient was able to easily continue in the outpatient or rehabilitation setting . FurtherThird, the patient presented in the context of chronic malnutrition and significant weight loss. The relationship of these features to the development of CIDP in this case is unclear. Severe polyneuropathy may develop as a delayed complication in patients who have had bariatric surgeries, separate from measured vitamin or nutritional deficiencies. This suggests that rapid weight loss may trigger immune and inflammatory injury to neurons, which could potentially be of some relevance in this patient . HoweverOverall, more research is needed into the mechanisms of the development of CIDP, perhaps especially in the pediatric population. The variability in presentation and different responses to therapy suggest that there may be multiple factors at play in its pathogenesis. The use of additional biomarkers would be helpful in delineating various subtypes from one another, especially those that respond differently to treatment, which may improve treatment outcomes. Patients should be counseled about the nature of the disease process with treatment and followed to monitor its course.CIDP is an immune neuropathy that may present a significant diagnostic challenge to a clinician, especially if the presentation is atypical. This case was atypical as it affected a pediatric patient, which is rare and as such can lead to a delay in diagnosis. Further, the pathophysiology was predominantly that of an immune polyradiculopathy, which made the diagnosis more challenging electrodiagnostically.Making an accurate and timely diagnosis of CIDP is important, as it can guide treatment decisions. However, the understanding of the association between CIDP subtypes and response to treatment remains incomplete. Further research is needed to identify the pathophysiologic underpinnings of this diagnosis, particularly in the pediatric realm, which could provide additional insight into treatment selection.