Some of the noise-intensive processes in dental laboratories include the finishing of crowns, bridges, and removable partial dentures; blowing out workpieces with steam and compressed air; and deflating casting rings. High sound pressure levels are also present in dental vibrators, polishing equipment, and sandblasters. The aim of this study was to Evaluation of the effect of noise production in dental technology laboratory on dental technician hearing capacity.For this cross-sectional study, a total of 120 dental technicians were chosen. Otoscopic evaluation and the Weber test were used to establish if they had sensorineural or transmission hearing loss at 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz, respectively. Then an OAER (objective auditory evoked response) and PTA  test were administered . The whole procedure was carried out by an audiologist and an ENT specialist.The PTA results showed that the patient had mild hearing impairment overall, with the loss being more severe in the left ear than in the right. The OAE test results revealed that in-ear of the left side, 84.5% of subjects passed and 15.5% of subjects struggled and were referred to an ear specialist, whereas in the right ear, 82.7% of subjects passed and 17.3% struggled and were referred to an ear specialist. According to this study, in a right-handed study participant, the ear on the left side is more vulnerable than the right side. Differences in the mean hearing threshold at 4000 and 6000 Hz in the left ear were statistically significant in the groups of workers with eleven to fifteen years of practical experience and twenty-one to twenty-five years of practical experience, respectively .A statistically meaningful threshold shift from 4000 to 6000 Hz is observed as the working experience grows, and this is suggestive of sensorineural hearing impairment brought on by the noisy dental environment. The act of perceiving sound is an intensely personal encounter, fundamentally intertwined with the nuances of individual auditory processing. Sound waves, as they traverse the atmospheric medium in the form of radiant energy, culminate in a range of auditory experiences that are as diverse as the listeners themselves .The complex spectrum of auditory perception includes both noise and sound, each with distinct connotations and physiological effects. Noise, often denoted as an unwelcome medley of discordant tones, presents a stark contrast to the perception of sound, which may be regarded as either soothing or disquieting depending on the listener's interpretation. These perceptions oscillate on a subjective pendulum, varying from one individual to another, and underscoring the highly personalized nature of auditory perception , 2.In this intricate labyrinth of sound and noise, what resonates as melodious harmony for one might register as disturbing cacophony for another. Long-standing exposure to what is perceived as noise can instigate not only irritation but potentially trigger a tangible discomfort, even pain . Over tiThe profundity of this personal experience underscores the imperative for an increased understanding of the interplay between auditory perception and its long-term effects on our hearing health. It necessitates a thoughtful conversation around the nature of our soundscapes and the impact of prolonged noise exposure, with a view to safeguarding our auditory wellness in an increasingly cacophonous world –7. StatiSensorineural hearing loss is characterized by impairment or damage to the structures within the inner ear, resulting in compromised auditory function. It typically involves harm to the hair cells in the cochlea that are instrumental in transmitting sound signals to the brain . The mosFollowing presbycusis, noise-induced hearing loss, or NIHL, is the next most common form of sensorineural hearing impairment. NIHL arises from damage to the delicate components of the inner ear due to excessive exposure to loud noises . These nStudies in the field of dentistry have revealed that a significant number of dental technicians are at risk of hearing loss . ResearcSome noise-intensive procedures in dental laboratories include finishing crowns, bridges, and removable partial dentures; clearing workpieces with steam and compressed air; and deflasking casting rings . Dental However, it is highly unlikely that a dental assistant would solely grind metal or keep the trimmer running continuously throughout the day. There are typically breaks in the noise, allowing the ears some respite. According to Directive 2058 of the Association of German Engineers (VDI), a daily noise level below 85 dB is generally considered "non-hazardous" even with long-term exposure . The VDIPure-tone audiometry (PTA) is the first test to quantitatively assess hearing loss, allowing for the evaluation of the type and degree of impairment in individuals aged and older. Otoacoustic emission (OAE) testing can also be employed to detect early indications of inner ear anomalies. These hearing assessments can contribute to primary prevention planning and the prevention of hearing loss . At thisDespite references in the literature to dental noise-induced hearing loss, there are limited precautions or regulations in place to prevent these disturbances from causing hearing damage in dental laboratories. Consequently, the study aimed to examine the impact of noise levels in dental laboratories on dental technicians' hearing.In dental clinics and laboratories, dental technicians are constantly exposed to noise originating from various dental instruments. The effect of chronic exposure to these noise levels on the hearing ability of dental technicians had not been sufficiently explored. The long-term exposure to noise might be affecting the hearing performance of these professional. Leading to potential hearing impairment or loss.This study aims to investigate whether continuous exposure to noise in the dental workplace hasa quantifiable impact on the hearing performance of dental technicians. It will also explore what measures, if any, are being taken to protect dental technician’s hearing and whether they are effective.There is no statistically significant difference in the hearing performance of dental technicians who are exposed to professional noise.There is statistically significant difference in the hearing performance of dental technicians who are exposed to professional noise.The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Research Ethics Committee at King Khalid University, Saudi Arabia . The study protocol was developed, and all subjects gave their written informed consent for inclusion before they participated in the study. The process of recruitment involved reaching out to potential participants, either through direct phone calls or face-to-face interactions. During these communications, the possible impacts of instrument noise on auditory health were clearly explained to them. The individuals were then invited to participate in this cross-sectional study that seeks to explore the correlation between such noise exposure and potential hearing loss. This proactive approach ensures that potential participants are fully informed about the study's aims, the nature of their involvement, and the potential benefits of the research.A cohort comprising 120 dental technicians was enrolled to evaluate the prevalence of sensorineural or conductive hearing loss at frequencies of 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz  and an otoacoustic emissions (OAE) test .A team of experienced audiologists and otolaryngologists collaborated in executing the entire diagnostic procedure. The acquired data were subjected to rigorous statistical analysis utilizing Tukey's honest significant difference (HSD) test and two-way analysis of covariance (ANCOVA) for computational and comparative purposes, respectively. The analysis of the data was performed with the assistance of SPSS software, version 23.0 . To identify results that were statistically meaningful, we set a P-value threshold of less than 0.05. Any results meeting this criterion were considered to demonstrate statistical significance.The PTA results indicated that the patient had an overall mild hearing impairment, with the left ear experiencing a more significant loss than the right ear. The OAE test results demonstrated that in the left ear, 84.5% of subjects passed and 15.5% struggled and were referred to an ear specialist. In the right ear, 82.7% of subjects passed and 17.3% struggled and were referred to an ear specialist  for individuals aged 51–55  constitutes a significant health concern, notably affecting an individual's auditory capabilities. It is distinguished by a gradual, unyielding encroachment of bilateral sensorineural hearing impairment, evolving incrementally yet relentlessly over a protracted duration, often spanning multiple years .ONIHL, a specific type of hearing loss, doesn't develop in a spontaneous or capricious manner; rather, its onset is an intricate process that accumulates over prolonged timeframes. The critical causative factor is typically the individual's enduring or intermittent exposure to excessive decibel levels within their vocational milieu , 36.The term "noise" in this context is perhaps a misnomer, for the auditory stimuli in question far surpass the conventional parameters of loudness. Instead, these pervasive sounds eclipse the realms of normalcy or safety, entering the territory of potential auditory trauma, gradually eroding the individual's hearing acuity , 37.This particular occupational peril accentuates the cardinal role of adequate auditory protective measures and rigorous noise regulation within working environments. Such preventative strategies are particularly pertinent in settings inherently characterized by high-decibel operations. The insidious nature of ONIHL, coupled with the potential for irreversible auditory damage, amplifies the urgency for implementing comprehensive noise mitigation and hearing preservation measures in workplaces prone to elevated sound levels .Therefore, the topic of ONIHL necessitates broader discourse and practical interventions, given its widespread implications for the workforce's auditory health and overall quality of life. The establishment of preventive measures, increased awareness, and timely interventions can significantly attenuate the adverse impacts of this pervasive occupational hazard .Hearing impairment that results from the natural aging process or is determined by genetic predispositions unfortunately remains beyond the realm of prevention. However, an entirely different scenario presents itself when we consider noise-induced hearing loss. This specific type of hearing damage, which arises due to consistent exposure to loud environments, can indeed be effectively prevented. One can guard against such auditory damage by utilizing appropriate protective gear in environments characterized by high noise levels. This includes the use of specific auditory protection devices such as ear plugs and ear muffs. These tools serve as an effective barrier, significantly reducing the level of noise that reaches the eardrum, thereby mitigating the risk of noise-induced hearing damage. By integrating such protective measures, we can effectively safeguard our auditory health in noise-intensive situations .Long-term exposure to such noise, particularly in occupational settings, can cause significant discomfort and may ultimately lead to hearing loss. Numerous studies in the field of dentistry have revealed that a substantial proportion of dental technicians are at risk of developing hearing loss, often beginning around the age of 35 , 21.This susceptibility to hearing loss can be attributed to various factors, including the nature of the dental work environment, which often involves high noise levels from equipment and machinery. Dental technicians are exposed to these noise levels on a regular basis, and without proper precautions, the constant exposure can contribute to the gradual deterioration of their hearing capabilities .Despite the literature linking noise in dental laboratories to hearing loss, there are limited protective measures or regulations in place to mitigate its occurrence. Consequently, this study aimed to evaluate the impact of noise on the hearing of dental laboratory employees. The Pure Tone Audiometry (PTA) results revealed mild hearing impairment overall, with greater severity in the left ear. The Otoacoustic Emissions (OAE) test results demonstrated that 84.5% of subjects in the left ear passed, while 15.5% struggled and were referred to an ear specialist. This outcome aligns with earlier investigations by Zubick et al. and Alabdulwahhab et al. , 40, whiTo determine personal noise exposure in the laboratory, one must calculate the daily exposure level. The Institute for Prevention and Occupational Medicine of the German Social Accident Insurance  providesThe analysis showed that the left ear was less effective than the right ear in right-handed individuals. Workers with 11–15 years and 15–25 years of experience exhibited a significantly different mean hearing threshold shift at 4000 Hz and 6000 Hz in the left ear. Additionally, a statistically significant difference was observed in the left ear's Distortion Product (DP) amplitude at 6000 Hz and 8000 Hz for those aged 51–55.In 2016, Dr. Brusis  reiteratDespite these efforts, noise in the laboratory can be bothersome and cause long-term stress. In an online survey conducted by the Association of Medical Professions in April 2019, 71.5% of the 1,170 dental technicians assessed their work stress on a scale of zero (low) to ten (very high) as ranging between seven and ten . Nearly This indicates that nearly three-quarters of the respondents experienced significant psychological stress during their work in the laboratory. For self-employed master dental technicians, this figure reached 73 percent, while for apprentices, it was already 56.5 percent. The primary reason cited for this high stress was time pressure (average rating 7.78), followed by workload (7.31), and in third place, physical stress resulting from noise, dust, prolonged sitting, and work involving microscopes, among other factors (7.03). This demonstrates that noise in the laboratory is not only a nuisance but also a significant source of stress for dental technicians .Although the noise exposure in dental laboratories is typically not high enough to pose a risk of hearing loss, it is still advisable to minimize noise exposure. Noise-induced stress can trigger the release of hormones such as adrenaline, noradrenaline, and cortisol, potentially leading to increased blood pressure and reduced concentration and work quality. Prolonged exposure may also cause headaches, muscle tension, digestive issues, and sleep disturbances . As a rePrevious research on the decibel levels of various dental handpieces and equipment reached similar conclusions, with laboratory instruments producing the highest decibel levels (up to 85.3 dB). OSHA regulations stipulate that an 8-h daily exposure to noise levels of 85 dB is acceptable . DentistThe dental stone cutter (92.0 dB) was identified as the loudest piece of equipment in the dental lab, while the denture-polishing unit was the quietest (41.0 dB) . ContinuIt is widely established in scientific literature that exposure to noise levels exceeding 85 decibels for extended periods, especially without the use of any form of ear protection, can lead to hearing loss. Such instances of noise-induced hearing loss are well-documented, thereby accentuating the risk posed by high-decibel environments –52. ConsHearing is indeed an intimate process, as sound waves travel through the air. Pure-tone audiometry (PTA) is the first statistically quantifiable test for hearing loss and can assess the type and degree of impairment in individuals aged four and older. Otoacoustic emissions (OAE) testing can also detect early signs of inner ear abnormalities . These hIn the context of this study, standardization of the exposed noisy environment for each participant was achieved through rigorous controls and procedures. We ensured that all participants were exposed to similar noise levels by monitoring and calibrating the equipment consistently across different laboratory settings. Additionally, all dental technicians were instructed to follow the same protocols, and we used precise instruments to measure the noise levels to which each participant was exposed.However, it is important to acknowledge that complete standardization of noise exposure in a real-world laboratory setting can be challenging. Variability in individual work practices, slight differences in equipment across laboratories, and the influence of other environmental noise factors could introduce some degree of variation. While every effort was made to minimize these potential sources of discrepancy, they might still represent a limitation of the study. Future research could focus on further refining the standardization process or employing additional controls to mitigate this limitation.In conclusion, this study underscores the potential risk of hearing loss in dental technicians due to prolonged exposure to noise in dental laboratories. While the noise levels generally do not exceed the hearing loss threshold, consistent exposure can lead to a gradual decline in hearing, predominantly in the left ear of right-handed individuals. However, it's worth noting that the standardization of the exposed noisy environment for each participant may present a limitation, as complete control over individual work practices and environmental noise factors may vary. Despite this, the research emphasizes the urgent need for increased awareness, protective measures, and regulations, including improved equipment design, individual hearing protection, and soundproof work areas to mitigate the risk of noise-induced stress and long-term hearing impairment.


Lawsonia intracellularis is the etiologic agent of porcine proliferative enteropathy (PPE), an inflammatory bowel disease with a major economic impact on the pig industry. The serological diagnosis of PPE can be performed using Blocking or Indirect ELISA, Immunoperoxidase Monolayer Assay (IPMA) and Indirect Fluorescence Antibody Test (IFAT). Here, we designed a most sophisticated immunological method for the detection of porcine anti-L. intracellularis IgGs, named Flow Cytometry Antibody Test - FCAT. This assay uses whole, live-attenuated L. intracellularis bacteria derived from a commercial vaccine. For the assay, we set up the optimal antigen concentration (106 bacterium/assay), primary antibody dilution (1:100), time of incubation (20 min), antigen stability (15 days), precision (coefficient of variation - CV < 10%), reproducibility (CV ≤ 13%) and Receiver Operating Characteristic (ROC). When using a cut-off of >15.15% for FCAT, we determined that it showed a sensitivity of 98.8% and specificity of 100%. The rate of agreement with IPMA was 84.09% with a kappa index of 0.66. FCAT was used to screen 1,000 sera from non-vaccinated pigs housed in 22 different farms and we found that 730 pigs (73%) from 16 farms (72.7%) had L. intracellularis IgG. This high prevalence confirms that L. intracellularis is endemic on Brazilian pig farms. Finally, we determined that FCAT is an easy to perform diagnostic assay and we would highly recommend it for: i) seroepidemiological studies; ii) evaluation of infection dynamics; and iii) characterization of the humoral response profile induced by vaccines. The dis Kingdom 0%, Brazia (100%)  illustraL. intracellularis can be confirmed by different assays, which can be used according to the type of biological sample collected. During post-mortem investigations, histological analysis complemented with Warthin-Starry silver staining ].The diagnosis of staining , immunohstaining , and in dization  can be uin feces . ELISA  are available and whose sensitivity (Blocking ELISA) close to 72% is considered low. Furthermore, although it is possible to use IFAT and IPMA techniques for detecting anti-L. intracellularis IgG, in practice, few laboratories around the world offer these assays as a service, mainly due to the difficulty of cultivating L. intracellularis. Therefore, the use of serology to understand the infection dynamic or general sanitary condition of the farm for L. intracellularis is limited.Serological diagnosis is an excellent tool for assessing the kinetics of infection, the profile and duration of passive immunity, and the potency and duration of the vaccine-induced antibody response. Although these data can be easily obtained for other pathogens such as porcine circovirus type 2 and Influenza A virus, for which several commercial diagnostic kits with high sensitivity and specificity are available, this is not the case for L. intracellularis. This test, named Flow Cytometry Antibody Test (FCAT), uses a live-attenuated strain of L. intracellularis as detecting antigen readily available from a commercial vaccine. FCAT has high sensitivity and specificity, is easy to perform, and can be promptly incorporated into the diagnostic routine of any specialized laboratory around the world.In order to overcome the limitations described above, in this study we used an innovative strategy to develop a new serological diagnostic test to detect antibodies against 22.1All sera used in this study came from: i) other studies previously approved by the Ethics Committee for the Use of Animals in Research at the Universidade de Passo Fundo ; ii) routine of diagnosis of the AFK Imunotech Laboratory; iii) other studies previously approved by the Ethics Committee for the Use of Animals in Research at the Universidade Federal de Minas Gerais .2.2in vitro cultivation of L. intracellularis is extremely difficult, which limits the production of this bacterium to few laboratories in the world. Since our objective was to develop a serological assay that could be easily performed in any laboratory, we used the vaccine strain of L. intracellularis from Enterisol® Ileitis (Boehringer Ingelheim), a live attenuated vaccine, as a source of antigen. This licensed vaccine is distributed worldwide, and all new batches of live antigen are qualified by the manufacturer, an ideal situation to guarantee antigen quality and ensure repeatability between antigens batches and laboratories that will perform this diagnosis.The 2.3cut-off values of this flow cytometry antibody test . The second set of specimens included 1,200 serum samples collected between 2018 and 2021 from 32 farms located in Southern region of Brazil  ; this panel of sera was used to analyze the ability of the established cut-off to identify conventional pigs with or without anti-L. intracellularis IgGs.A total of 246 serum samples obtained from pigs with different serological condition were used to determine the preliminary 2.4L. intracellularis; ii) bacterial morphology; and iii) antigenicity. For the first two analyses, a daily aliquot of the antigen was diluted 1:1,000 in filtered PBS pH 7.4 and acquired in the cytometer. The number of bacteria per microliter of acquired samples was calculated automatically by the cytometer which was equipped with flow sensor used for volumetric measurement. Therefore, to calculate the total number of bacteria per mL of the reconstituted vaccine, we used the following mathematical formula: number of events per μL × inverse of the dilution factor  × per 1,000 (to convert μL to mL). The morphometric analysis was conducted analyzing the parameters of Forward Scatter (FSC) vs Side Scatter (SSC) of the daily aliquot of the antigen. For the antigenicity analysis, 3 sera from pigs immunized with the Porcilis® Ileitis vaccine were used; briefly, 106 bacteria were incubated into the wells of a 96 well conical-bottom polystyrene plates  together with 100 µL of porcine serum diluted 1:100 in filtered  PBS pH 7.4 containing 1% bovine serum albumin  (FACS buffer) for 1 hour at 37°C. After three washing steps with 200 μL of FACS buffer , 100 μL of FACS buffer containing 1 μg of Goat anti-Porcine IgG(H+L)-PE  was added and incubated for 1 hour at 37°C. Then, the washing steps were repeated, and the bacterial pellet resuspended in 350 µL of PBS for analysis. All parameters were analyzed by Flow Cytometry using a FACSVerse Cytometer  equipped with a 405 nm violet laser, 488 nm blue laser, 640 nm red laser and flow sensor. A total of 100,000 events were acquired in P1 region and analyzed. Each sample was analyzed in triplicate.The stability of the reconstituted antigen was evaluated daily for a period of 30 days. Three parameters were analyzed by flow cytometry: i) absolute count of 2.55, 106 and 107) of L. intracellularis were evaluated. Each concentration was incubated with a panel of sera (n=5) with different titers of anti-L. intracellularis IgG as defined previously by the IPMA  different dilutions of a panel of highly positive , moderately positive  and negative (n=5) sera were analyzed. The dilutions evaluated were 1:50, 1:100 and 1:200 in a final volume of 100 µL. The immunostaining was performed as described above (subsection 2.3).2.7To investigate the shortest incubation period necessary to guarantee the optimal interaction between the molecules involved in the assay, three incubation periods were evaluated: 60 min, 30 min and 20 min. These periods were evaluated for primary (10 different positive samples) and secondary (Goat Anti-Porcine IgG (H+L)-PE) antibodies. All incubations were performed at 37°C. The immunostaining was performed as described above (subsection 2.3).2.8L. intracellularis antibodies using a commercial blocking ELISA Kit . The protocol was performed following the manufacturer’s recommendations.A total of 100 samples Table 1 2.9L. intracellularis IgG. This assay was carried out by the laboratory of Prof. Roberto Guedes , according to the methodology previously described (The immunoperoxidase monolayer assay (IPMA) was used to detect porcine anti-escribed .2.106L. intracellularis suspended in 200 µL was added per well of a 96 well conical bottom polystyrene plates. The plate was centrifuged  and the bacterial pellet was resuspended in 100 µL of porcine serum diluted 1:100 in FACS buffer and incubated at 37°C during 20 min. After three washing steps with 200 μL of FACS buffer , 100 μL of FACS buffer containing 1 μg of Goat Anti-Porcine IgG(H+L)-PE was added and incubated for 20 min at 37°C. Then, the bacteria were washed 3 times, resuspended in 350 µL of FACS buffer and transferred into a round-bottom tube . A total of 100,000 events were acquired in a FACSVerse cytometer. The bacterial population was initially identified through a dot plot crossing the FSC and SSC parameters; where the study region, designated P1, was established. Subsequently, a second dot plot was created, in this case, crossing the FL-2  and FL-4  channels and having P1 as the study region. The events considered positive were those enclosed within the quadrant representative of PE (low right). The results are expressed as the percentage of positive bacteria in relation to the total bacteria contained in the P1 region. The step-by-step execution of this diagnosis as well as the analysis strategy are illustrated in A total of 102.11cut-off was performed using a panel of 198 porcine sera . Briefly, sera from 78 animals known to be negative for anti-Lawsonia intracellularis IgG and molecularly (qPCR) negative for L. intracellularis were obtained. We also obtained sera from 40 animals from a genetic nucleus herd with no history of Ileitis; these animals were molecularly negative for L. intracellularis; collectively sera from a total of 118 negative animals. We used sera from 80 animals serologically positive for L. intracellularis; of these total, 60 SPF pigs were vaccinated (qPCR negative), and 20 were experimentally infected (and consequently qPCR-positive). Therefore, the cut-off calculation, performed using the Receiver Operating Characteristic (ROC) Curve, included 118 negative and 80 positive animals. All sera were tested by this new assay and the results were used to generate a Receiver Operating Characteristic (ROC) Curve. The selected cut-off was based on the sensitivity and specificity values. The ROC Curve analysis was performed using Graph Pad Prism Software Version 9.2.0.The determination of the ine sera Table 12.12L. intracellularis, which is the analyte of interest. The analysis was performed as recommended by Selliah, Eck  from SPF pigs immunized with Glaesserella parasuis , Pasteurella multocida A , Salmonella enterica, serovar Choleraesuis , Clostridium perfringes type C and Escherichia coli  and Porcine circovirus type 2  were assessed using the protocol described in subsection 2.8.The specificity analysis was conducted to evaluate the ability of this assay to identify IgG specifically to iah, Eck . Brieflywith SV7 , n=8), M2.13® Ileitis) and negative SPF pigs were tested twice under the same conditions by a single analyst. With the values obtained from each sample, the mean and coefficient of variation were calculated. For reproducibility analysis (inter-assay precision) the same samples were analyzed by 2 different analysts on 2 different days. Again, with the values obtained from each sample, the mean and the coefficient of variation were calculated. The accuracy acceptance criterion was established by accepting a coefficient of variation between the analyses of the same analyst or between the analysts of a maximum of 25%.Precision is one of the most critical parameters in flow cytometry assay . In orde2.14® Ileitis vaccine at 21 days of life and G2) pigs (n = 8) inoculated with PBS. Serum samples were collected prior to vaccination (D0) and at the following post-vaccination times: D7, D14, D21, D28 and D55 contributing to 88 sera for comparative purposes. Agreement analysis (Kappa) was performed as described by Landis and Koch  pigs (n = 8) immunized with the Porcilisand Koch .2.15All data were analyzed using GraphPad Prism™ . One or two-way ANOVA with Tukey’s multiple comparisons test were used to assess significance between the different variables analyzed in this study. The specific test used in each analysis, as well as the significance, is indicated in the figure legends.33.1L. intracellularis obtained from the attenuated vaccine Enterisol® Ileitis was used as a diagnostic antigen. The antigen used in our study is destined to immunizing pigs and should be immediately used upon reconstitution. In the test designed here, the amount of antigen used in each assay is low and a single reconstituted bottle contains enough antigen to be used along a few weeks. Thus, the stability and quality of the reconstituted and refrigerated (4 – 8°C) antigen was analyzed daily along a 30 days period. During this time, changes in the morphology of the bacterial population  were observed after 15 days of antigen storage  immunostained with 3 categories of sera, weakly, moderately, and highly positive as determined by IPMA. As illustrated in 7, in which weakly and moderately positive sera could not be statistically differentiated. There is a reduction in the percentage of detection of L. intracellularis between concentrations of 106 and 107, when using weakly and moderately positive sera (5 bacteria was lower (long acquisition period) compared to 106 and 107, indicating that part of the bacteria was lost during the washing steps; therefore, the concentration of 106 was defined as the ideal concentration of antigen.The amount of antigen used in a diagnostic test must be evaluated with two objectives: i) functionally (to ensure maximum resolution of the test) and ii) economically (antigen saving). Taking these premises into account, we analyzed 3 concentrations of antigens  when sera diluted 1:200 were used, and the number of sera considered positive (cut-off set at 15.15% as described in the section 3.5) at lower dilutions (5/5) decreased when the weakly positive sera category was tested (2/5) (The dilution rate of the serum (primary antibody) is essential in any diagnostic test and should be set to mitigate false positive results, usually associated with polyreactive IgGs. Three serum dilutions were analyzed; 1:50, 1:100 and 1:200. We observed that there was no reduction in the percentage of ed (2/5) Figure 53.4L. intracellularis) and secondary (Goat anti-Porcine IgG-PE) antibody were tested. As illustrated in L. intracellularis with associated IgGs at the 3 different incubation times was 47.5%, 47.1% and 48.0%; additionally, the same dispersion profile of the results was observed, and no significant differences were found between the analyzed times. In view of these results, an incubation time of 20 min was selected for the primary and secondary antibodies.Evaluating antibody incubation time (primary and secondary) is essential in any diagnostic test under development; in general, it is always recommended to select the shortest time, as long as there are no changes in the final result of the diagnosis. Three incubation times  for both the primary  aiming to find the cut-off value capable of truly differentiating a positive from a negative serum sample. For this purpose, a ROC curve analysis was conducted using 118 serum samples negative and 80 serum samples positive to L. intracellularis antibodies  was recommended; and at this cut-off value, the relative sensitivity and specificity estimates were 98.8% [95% confidence interval (CI) = 93.2% to 99.9%] and 100% (95% CI = 96.9% to 100%), respectively. The ROC curve had an Area Under the Curve (AUC) value of 0.9963 (95% CI = 0.99 to 1.0), which indicated a high level of accuracy for this FCAT  was tested on the FCAT. As illustrated in cut-off of 15.15%; therefore, all sera were considered negative for L. intracellullaris. This result demonstrates that there is no cross-reactivity between L. intracellularis and G. parasuis, M. hyopneumoniae, P. multocida A, Salmonella enterica, serovar Choleraesuis, E. coli, C. perfringes type C and Porcine circovirus type 2. Finally, a third panel of sera  from: i) non-vaccinated conventional pigs [L. intracellularis (qPCR) negative feces]; ii) non-vaccinated conventional pigs [feces positive for L. intracellularis (qPCR)]; and iii) Vaccinated  conventional pigs, was evaluated in the FCAT. As shown in ® Ileitis vaccine developed antibodies against L. intracellularis and were therefore considered positive. Similarly, 85.3% of the animals that were shedding L. intracellularis in the feces had anti-L. intracellularis IgG at a level higher than the FCAT cut-off; and 68.7% of the animals that were not shedding L. intracellularis at the time of blood collection had previous contact with L. intracellularis.Once the definition of all parameters and conditions of the Flow Cytometry Antibody Test (FCAT) was concluded, a wide panel of swine sera was used (3.6The precision (intra-assay) and reproducibility (inter-assay) analysis were performed by two different analysts (A and B). As described in the 3.7To analyze the level of agreement between FCAT and IPMA, sera collected from two groups of pigs (vaccinated and unvaccinated) at different post-vaccination periods were analyzed by these two methodologies in two different laboratories (FCTA conducted at the Frandoloso’s lab and IPMA conducted at Guedes’s lab). To avoid any bias, the analysis was blind, and the history of the sera was not revealed to the analysts. As described in L. intracellularis. As illustrated in L. intracellularis IgG as determined by the IPMA day (D) 7 , D14  and D21  post inoculation with PBS (L. intracellularis IgG by FCAT.Considering that the pigs used in this experiment were Specific Pathogen Free and kept in a controlled facility (BSL-2) throughout the study, our expectation was that all animals, regardless of the diagnostic technique, would be negative for with PBS Table 3.L. intracellularis IgG during the genesis of humoral response induced by vaccination is one of the most important features. We noticed that both techniques are very similar in terms of sensitivity; however, FCAT standing out slightly over IPMA on D14, at that moment the FCAT classified more animals as positive than the IPMA.The sensitivity to specifically detect the analytical, in our case the anti-4Lawsonia intracellularis is a complex intracellular bacterium ubiquitously found in the pig production system worldwide  and intradermally (Porcilis® Lawsonia ID). The effectiveness of these vaccines has already been scientifically demonstrated    and systal (IgA) . The immal (IgA) –30, a feal (IgA) . TherefoL. intracellularis infection for pig production is unquestionable, in this study we present a new method of serological diagnosis for L. intracellularis, named Flow Cytometry Antibody Test. Flow cytometry has been used to quantify the percentage of eukaryotic cells which had taken up or were associated with fluorescent L. intracellularis , specific (100%) and takes approximately only 1:15 hours to run, which represents a time saving compared to Blocking ELISA, Indirect ELISA, IPMA and IFAT of 47%, 8%, 33% and 12%, respectively. Although the specificity of IPMA and FCAT are the same (100%), the sensitivity of the FCAT method (98.8%) is much higher than IPMA (89%), IFAT (91%) and Blocking ELISA (72%) (Since the negative impact of llularis . As descSA (72%) Table 5.L. intracellularis is used in the test ; ii) the antigen is not chemically (acetone and methanol) treated during the test [all antigens (protein lipids and saccharides) remain native]; iii) the entire surface of the antigen is accessible to antibodies ; and iv) the fluorescence reading is performed automatically by Flow Cytometry Equipment, and therefore, mitigates human errors (e.g. subjective counting)  live ounting)   . In thisL. intracellularis antibodies can be performed by ELISA. As illustrated in L. intracellularis have accessibility to the diagnostic antigen, and therefore, the sensitivity of the technique is greater. The Indirect ELISA . For this purpose, it is necessary to use specific antibodies . The flexibility of FCAT is ideal for studying the immunological profile of licensed vaccines as well as vaccines under development against L. intracellularis. Furthermore, as described in As already mentioned, the main objective of this study was to develop a method of serological diagnosis for L. intracellularis. Additionally, one disadvantage of FCAT relative to other diagnostic techniques is the need for the diagnostic laboratory to have a flow cytometer instrument, which is more expensive than an ELISA reader (for the ELISA technique) or a microscope (for the IPMA and IFAT techniques). However, what may be considered expensive today may become affordable in the medium term (such as the situation with polymerase chain reaction machines for example).A limitation of FCTA, like ELISA, IPMA and IFAT is that it is not possible to differentiate, based on the presence of systemic IgG, vaccinated animals from those naturally infected with L. intracellularis diagnosis, but future studies need to be carried out to develop, on an industrial scale, the other reagents for this diagnosis, such as positive and negative control sera, and conjugated secondary antibodies, which will increase the repeatability of the results and avoid any variations related to the quality and specificity of the commercial reagents (controls and secondary antibodies).We recognize that we have taken an important step towards improving L. intracellularis, in addition to produce Ileitis in pigs, also causes an intestinal disease in horses called equine proliferative enteropathy (EPE), which cases have been increasing in the last few years, especially in post-weaning foals and occasionally in adult horses  and indicates a high prevalence of L. intracellularis in Brazilian pig farms. The national prevalence found here is higher than those previously reported in the state of Minas Gerais (37%)  to mitigate the economic losses caused by this pathogen. Future seroepidemiological studies using the FCAT are needed to better estimate the impact of L. intracellularis on Brazilian pig herds.Finally, using the FCAT we analyzed the prevalence of circulating antibodies in a total of 1,000 pigs not vaccinated against is (37%) , which iThe original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author.The animal study was reviewed and approved by Ethics Committee for the Use of Animals in Research at the University of Passo Fundo . Ethics Committee for the Use of Animals in Research at the Federal University of Minas Gerais (CEUA n° 133/2018. 36/2016).Conceived and designed the experiments: RF. Performed the experiments: DZB, JAG, and GCPF. Contributed reagents/materials/analysis tools: RF, LCK, CF, and RMCG. Wrote the paper: DZB, RF, and LCK. Critical review and editing of the manuscript: RMCG, HLW, and SV. All authors discussed the results and commented on the manuscript. All authors contributed to the article and approved the submitted version.


The age range of 15 to 59 years accounted for 42.3% of all diseases of the inner ear hospital admissions. Around 59.6% of all admissions were made by females. The female admission rate increased by 210.1% (from 12.43 (95% CI 12.01–12.85) in 1999 to 38.54 (95% CI 37.84–39.24) in 2020 per 100,000 people). The male admission rate for diseases of the inner ear increased by 169.6%  in 2020. Conclusion: Inner ear disease admissions increased markedly in England and Wales during the past two decades. Females and the middle-aged population were at higher risk of being admitted for inner ear diseases. Further cohort studies are warranted to identify other risk factors and develop effective prevention strategies.Background: Due to an expansion in the usage of medications (such as anticancer therapies), increased exposure to noise, and an increase in life expectancy, the prevalence of inner ear disease-related hearing loss is rising. Diseases of the inner ear are frequently accompanied by other conditions, such as chronic heart failure, systemic inflammation, arterial hypertension, and cerebrovascular disease. The aim of this study was to investigate the profile of hospital admissions linked to inner ear diseases in England and Wales. Method: This was an ecological descriptive study using public medical databases in England and Wales. Diagnostic codes for diseases of the inner ear (H80–H83) were used to identify all hospital admissions. Between 1999 and 2020, the chi-squared test was used to assess the difference between the admission rates. Results: From 5704 in 1999 to 19,097 in 2020, the total annual number of hospital admissions increased by 234.8%, which corresponds to a 192.3% increase in the admission rate [from 10.94 (95% CI 10.66–11.22) in 1999 to 31.98 (95% CI 31.52–32.43) in 2020 per 100,000 people,  Ear diseases are varied and can influence the sense of balance and hearing. Ear disorders can be categorised according to the part of the ear affected, i.e., the inner, middle, or external ear ,2. The iInner ear disorders involve the entire membranous labyrinth and are distinguished by the following three symptoms: vertigo, tinnitus, and sensorineural hearing loss. Primary pathology may include aberrant inner ear homeostasis, supporting cells, or inner ear hair cells leading to an alteration in the composition of the peri and endolymph, with direct influences on the function and integrity of the hair cells . ChangedThe most common inner ear-related dysfunction is age-related hearing loss . HearingThe existence of diseases of the inner ear is usually associated with other diseases and health problems, including chronic heart failure, systemic inflammation, arterial hypertension, cerebrovascular disease, diabetes, chronic kidney disease, asymptomatic atherosclerosis, obesity, coronary artery disease, and dyslipidaemia . In addiThis was an ecological descriptive study that was conducted using publicly available data for the period between April 1999 and April 2020 extracted from two medical databases in the United Kingdom: the “Hospital Episode Statistics” (HES) database in England and the “Patient Episode Database for Wales” (PEDW) ,14. We dAdmission rates were estimated using the number of finished consultant episodes of diseases of the inner ear-related admission divided by the mid-year population and presented with 95% confidence intervals (CIs). The age-specific admission rate was estimated by dividing the number of admission episodes for each age group by the mid-year population of that same age group in the same year. The same procedure was followed to estimate the gender-specific admission rate by dividing the number of admission episodes for each gender  by the mid-year population of males or females in the same year. The chi-squared test was employed to estimate the difference between the admission rates between 1999 and 2020. Analyses were conducted using SPSS version 27 .p < 0.01].The total annual number of diseases of the inner ear hospital admissions for various causes rose by 234.8%, which started from 5704 in 1999 and reached 19,097 in 2020, representing an increase in the admission rate of 192.3% . The male admission rate increased by 169.6%  .Admission rates for all inner ear diseases were higher among females compared to males .Diseases of the inner ear hospital admission rates for disorders of vestibular function and other diseases of the inner ear were directly related to age (more common among elderly patients aged 75 years and above) .This research is the first nationwide epidemiological study in the United Kingdom  to investigate the changes in hospital admissions and admission rates for inner ear disorders with comparison by age and gender over the period 1999–2020 based on representative data from the HES and PEDW medical databases.p < 0.01]. The increased admission rates can be justified by the increased prevalence rates of diseases of the inner ear with time. For instance, the 2003 prevalence of vestibular vertigo in Germany, as reported by Neuhauser et al. (2009), was 4.9%, while it was 6.5% in 2015 [Our finding showed that the total annual number of diseases of the inner ear hospital admissions for various causes increased by 234.8% from 5704 in 1999 to 19,097 in 2020, representing an increase in hospital admission rate of 192.3% [from 10.94 (95% CI 10.66–11.22) in 1999 to 31.98 (95% CI 31.52–32.43) in 2020 per 100,000 persons,  in 2015 ,17. Simi in 2015 ,19. IndeOne of the major otologic complaints among Emergency Department (ED) visitors is dizziness and vertigo . While tAnother important cause of inner ear disease complications is the presence of infectious diseases . MultiplWhile middle ear diseases are clearly diseases of children , the inpOur findings showed that all diseases of the inner ear hospital admissions were higher among females and thus confirm that females are more susceptible to inner ear disorders, which has already been revealed in previous epidemiological studies ,35,37. THormonal influences might also provide a partial explanation for our findings. Research on benign paroxysmal positional vertigo suggests that the rapid decrease in estrogen level disrupts otoconial metabolism within the inner ear and that hormonal therapeutic intervention successfully improves Ménière’s disease . TypicalHearing impairment (HI) is becoming more and more of a public health issue. Nearly two-thirds of the elderly population in the US has hearing impairment ,49, yet Indicating the effect of a disease or disability by counting the number of years of healthy life lost owing to illness or disability, the disability burden was most often stated in DALYs. According to Australian research, there are 48 million DALYs overall and 95,000 DALYs from HI per year ,55. A toThe financial burden of filing disability claims with the government or receiving workers’ compensation was a major factor in a lot of the studies on the economic effects of noise-induced hearing loss. Hearing loss accounted for 5.3% of all disability claims in the US, placing it second only to tinnitus . The amoIn addition to the expense of hearing loss treatment, such as audiologic exams and hearing aids, the causes of excessive medical spending among people with HI may be connected to an increase in falls, hospitalizations, cognitive decline , and depIn the United States alone, excess medical expenses for people with hearing loss are expected to range from $3.3 to $12.8 billion ,52. FoleEstimating indirect expenses is more challenging. Differences in employment rates and income inequalities may be used to estimate lost productivity. From $1.8 to $194 billion ,61, variThe database used to conduct the present work is a useful data source to provide epidemiological information on hospital admissions for inner ear disorders. There could be a potential source of miscoding regarding the diagnoses by health care providers, although miscoding was assumed to be equal for all age groups and both genders, and thus, the quality of the results remains unaffected. The prevalence of specific inner ear disorders “such as Ménière’s disease, vestibular neuritis, or benign paroxysmal positional vertigo” cannot be estimated from our study findings; however, we presented their specific admission rates, which could be a reflection of the actual prevalence of the diseases. The data of the two medical databases include readmission cases, which could lead to an overestimation of our calculated admission rates. The publicly available data are at the population level (aggregated data) and not at the individual patient level, which restricted our ability to examine the role of important confounding variables on the estimated admission rates.In England and Wales, over the past two decades, admissions for inner ear diseases have significantly grown. The likelihood of being admitted for inner ear diseases was higher in females and the middle-aged group. It is necessary to conduct additional cohort studies to find other preventable risk factors and create efficient prevention plans.


To identify and understand the evidence regarding hearing changes related to acquired Dengue, Chikungunya, and Zika virus infection in adult individuals.A scoping review was performed according to the recommendations of The Joanna Briggs Institute and guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews in the Embase, PubMed/Medline, ScienceDirect, Scopus, and Web of Science databases without restriction on language and year of publication. Case studies, observational studies, and clinical trials reporting hearing loss in adult subjects (>18–60 years of age) of both sexes with DENV, CHIKV, or ZIKV diagnosed by positive molecular/serological examination by RT-PCR or IgM/IgG by ELISA method were included.Thirteen studies met the inclusion criteria and were selected for review. The occurrence of auditory symptoms caused by arboviroses and the presence of permanent or transient sensorineural hearing loss was variable in adults.Dengue, Chikungunya, and Zika infections in adults are associated with a variety of auditory symptoms. The frequency of permanent or transient sensorineural hearing loss is low but not negligible. Dengue (DENV), Chikungunya (CHIKV), and Zika (ZIKV) are arboviruses of endemic co-circulation in Brazil.3The infection caused by these pathogens may result in immediate or late hearing sequelae that affect different age groups because of damage to the structures or functions of the inner ear.As for CHIKV, one studyEarly evidenceHowever, in adults, the actions of arboviruses on hearing are still poorly understood.13Therefore, the aim of this scoping review is to identify and understand the evidence regarding hearing changes related to acquired Dengue, Chikungunya, and Zika virus infection in adult individuals.The literature review was conducted according to the recommendations of The Joanna Briggs Institute (JBI) for scoping reviewsThe guiding research question “What hearing characteristics may be altered in adult individuals with confirmed DENV, CHIKV, and/or ZIKV infection?” was designed for the selection and search of the studies through the Population, Concept, and Context strategy. Thus, “P” was defined as adult patients (>18 years), “C” as hearing characteristics, and the last “C” as an infection acquired by the arboviruses of Dengue, Chikungunya, and Zika.The literature search was conducted up to October 31, 2022, using Embase, PubMed/Medline, ScienceDirect, Scopus, and Web of Science databases. The search strategy was tailored to each database and included descriptors and keywords related to arboviruses and hearing impairment (Supplementary Table 1). No age range limiters were used to ensure the retrieval of as many relevant studies as possible.Case studies, observational studies, and clinical trials reporting hearing loss in adult subjects (>18–60 years of age) of both sexes with DENV, CHIKV, or ZIKV diagnosed by positive molecular/serological examination by RT-PCR or IgM/IgG by ELISA method were included. There was no restriction on the year and language of publication.Studies that included individuals with hearing loss or complaints prior to infection, a history of exposure to constant noise (80 dBNa for more than 8 h/day), psychiatric disorders, and neurological and genetic syndromes, congenital or acquired prior to infection were excluded. In addition to in-vitro studies, animal studies, editorials, book chapters, reports, commentaries, notes, conference abstracts, and literature reviews.Data analysis occurred in four steps: identification, screening, eligibility, and inclusion. In the identification stage, appropriate studies were selected by individual database searches. The bibliographies of included studies were manually reviewed for additional references.The reference manager application RayyanFor analysis, information on study identification , study design, sample characteristics , presence and type of arbovirus, presence of associated neurological manifestation, hearing assessment method and hearing alteration were extracted in a Microsoft Office — Excel® spreadsheet.The grades of hearing impairment were reclassified to homogenize the results between the studies considering four-frequency Pure-Tone Average (4fPTA) by obtaining the means of the thresholds at 500, 1000, 2000, and 4000 Hz for each ear, and the values suggested by the World Health Organization as followsAfter searching the databases, 731 references of potential studies were identified, plus two references retrieved by manual search in the citations and references. After removing the duplicates, 335 articles were screened by reading the title and abstract, where 310 articles were excluded for not answering the guiding question of this research.The remaining 25 articles were assessed for eligibility by reading the full text. Of these, six articles were excluded for inappropriate study design and 4 for no auditory outcomes. A detailed overview of the study selection process is presented in the flow chart in A description of the identifying characteristics of the 13 included studies is presented in ,13,20,The studies were published between the years 200318Two studies mentioned neurological alterations associated with the researched arboviruses, one relating CHIKVFurthermore, the most commonly used hearing assessment method was tonal audiometry (n = 8 studies).The main hearing alterations in adult individuals with a confirmed infection by DENV, CHIKV, and ZIKV viruses are presented in Six studies20Three studiesThree studiesThis scoping review is the first study of its kind to provide systematic and semiquantitative insight that the presence of hearing alterations during infection with DENV, CHIKV, and ZIKV viruses in adult subjects agrees with previously published findings in other viral infections showing that the auditory system can be compromised to varying degrees of severity.The high endemic prevalence of dengue, especially in Brazil, where most studies were produced, associated with social and environmental issues, justifies why this has been the most studied arbovirus and is even related to hearing alterations.28An audiometry may have been the most widely used hearing evaluation method because it reveals the integrity of the peripheral auditory pathways besides accurately estimating hearing thresholds. However, since damage to the central nervous system has already been reported in adult individuals with ZIKV or CHIKV.The heterogeneity of hearing alterations in arboviruses is a common finding,Moreover, unreported pre-existing chronic comorbidities may have propitiated the hearing alterations, as exposed in the study by Diniz et al.,CHIKV has been associated with decreased hearing acuity with persistent auditory symptoms,34In ZIKV infection, auditory alterations are specific manifestations that can occur during acute infection, having the character of transient sensory-neural impairment of gradual spontaneous resolution.The molecular and morphological damage to cochlear structures by ZIKV infection has been explained by multiple complex mechanisms that contribute to hearing loss;38Because ZIKV is cytopathic to neurons, it infects microvascular endothelial cells in the brain, allowing viral access by impairing nuclear responses of innate immunity.A studyNeurological complications related to CHIKV and ZIKV arboviruses have been reported only in the most severe cases of arboviral infection or coinfection, demonstrating a rare viral neuropathic effect that is still poorly understood.24Inflammatory processes with demyelinating lesions in the cochlear nerve may cause hearing impairment,The main limitation of this research concerns the small amount of data that exists to characterize the hearing alterations in each arbovirus. Secondarily, the lack of homogenization between samples and the lack of objective data for measuring hearing function in some studies24Preliminary evidence supports those hearing alterations may occur during Dengue, Chikungunya, and Zika infections, with the variable occurrence of auditory symptoms and the presence of sensorineural hearing loss that may be permanent or transient. Otalgia, hypoacusis, vertigo/tinnitus, and tinnitus were the most common symptoms, and sensorineural hearing loss was more remarkable for patients exposed to the Zika virus.Audiological follow-up and treatment are suggested to reduce the severity of long-term auditory viral sequelae. However, due to the presence of limitations related to study designs, mainly by the high number of case reports and methodological limitations, the actual effect of arboviruses on hearing may be substantially different from the estimation in this review.Therefore, future studies should aim to establish the causal relationship between auditory alterations in larger samples affected by these arboviruses in order to define a clear mechanism that explains the auditory symptoms.No funding was received.The authors declare no conflicts of interest.


Introduction: Cochlear implantation in patients with Ménière’s disease (MD) is the treatment of choice in cases of functional deafness. Additional vertigo control is of central importance in this group of patients. Endolymphatic hydrops (ELH) is the pathophysiological correlate of MD and can be evaluated by magnet resonance imaging (MRI). Bilateral MD occurs in 10–33% and can be the reason for a postoperative persisting or newly occurring vertigo in this group. Recent developments in the field of implant magnets and experience in MRI sequences allow the diagnostic performance of MRI in cochlear implantees to be evaluated. The aim of the present study was to evaluate the possibility of MRI as a visual diagnostic tool for endolymphatic hydrops in cochlear implantees. Material and Methods: This was a retrospective study including three cochlear implantees  suffering from MD who, postoperatively, had a recurrence of vertigo with Ménière’s-like symptoms. An MRI was performed for the evaluation of ELH (ELH-MRI). MRI observation was performed by a 4 h iv. delayed Gad 3 D Flair sequence. Results: In all cases, the ipsilateral implant magnet artifact covered the vestibulum, the semicircular canals and the cochlea. The contralateral vestibulum, the semicircular canal and the cochlea were fully observable, and a classification of the ELH-MRI could be performed. Conclusion: ELH-MRI scanning allows for the detection of contralateral labyrinthine endolymphatic hydrops and is a tool for the postoperative evaluation of vertigo in cochlear implantees. Cochlear implantation (CI) is the treatment of choice for patients with deafness and insufficient speech perception with hearing aids. Besides these groups, subgroups of patients with comorbidities such as anatomical or structural anomalies, vestibular schwannoma and Ménière’s disease (MD) merit specific consideration for a CI.Patients with MD are particularly challenging because treatment for the hearing deficit and the vertigo needs to be addressed. The natural course of MD includes bilateral disease in 10–33% ,3,4,5. TDevelopments in MRI-based visualization have made it possible to estimate the labyrinthine endolymphatic hydrops (ELH), which is a pathophysiologic correlate of MD ,7,8,9. DThis highly important development in technology has made it essential clinical practice for cochlear implantees who suffer from MD, as those in this group have particularly challenging problems, since vertigo control is, in many cases, the central motivation for these patients due to the combination of hearing loss and vertigo with, in many cases, increasing attack recurrence.Since the development of a bipolar diametral implant magnet in 2014 , many problems with performing MRI in patients with cochlear implants have been addressed. MRI scans are now possible without complications in terms of pain and demagnetization up to 3 T and even without a head wrap .Specific positioning of the implant and the head inside the scanner have made it possible to visualize the cochlea and the internal auditory canal ,14,15 anThe artifact size related to the cochlear implant magnet is the key limiting factor for the clinical application of different sequences . BesidesThe effect of ELH specific sequences on the MRI artifact and therefore the visualization of the structures of interest  and vestibulum) in cochlear implantees is unknown.Another challenging point is the clinical value and interpretation of the state of an ELH in a cochlear implantee. The occurrence of vertigo after CI is well known and can be caused by different reasons such as vestibular receptor destruction, perilymphatic fistula, compensative problems, costimuation, etc. . KnowledThe results of previous studies suggest that the depiction of the inner ear, internal auditory canal and cerebellopontine angle by MRI in cochlea implantees depends on the used MRI sequence-related artifact. The aim of the present study was to evaluate the feasibility of assessment for ELH by an MRI on the ipsilateral and contralateral side in cochlear implantees, although there is an artifact.Patients: In this retrospective study, we examined three cochlear implantees . Two of them suffered from MD according to Barany society and AAOHNS 2015 ,25. In tOne patient showed functional deafness and Ménière-like symptoms. In cases of MD, we regularly perform an MRI to foreclose intra- and retrocochlear disorders and to gauge endolymphatic hydrops. All three patients had a recurrence of vertigo after the initial cochlear implantation. An MRI was performed to evaluate for endolymphatic hydrops. MRI-enabled cochlear implant systems were implanted in all patients, without the need to wrap the head during the MRI examination .MRI: Scanner and sequence: A 3 tesla MRI system  with a 16-channel array head coil was used. Gadobutrol at a dose of 0.2 mL/kg was applied intravenously 4 h before scanning. The imaging protocol consisted of a three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequence. The parameters for the 3D-FLAIR sequence were: time of repetition 6000 ms, time of echo 177 ms, time of inversion 2000 ms, matrix size 240,217, field-of-view 190 mm, slice thickness 0.8 mm, acquisition time 12 min.Graduation: The estimation of ELH grading was described for the vestibular part by using a four-stage graduation system  and for Ethics: The procedures conformed to the World Medical Association’s Declaration of Helsinki and were approved by the University of Münster Faculty of Medicine and Health Sciences Research Ethics Committee (reference: 2022-314-f-S). All participants gave their written informed consent.In all three patients, the artifacts being caused by the ELH-MRI sequence meant that it was not possible to visually evaluate the inner ear, the internal auditory canal or the cerebellopontine angle of the implanted side after CI.However, despite the artifact, the visualization of the inner ear, internal auditory canal and cerebellopontine angle by MRI of the contralateral side was possible. Even the visualization and graduation of an ELH of the non-implanted side was possible by means of the special hydrops sequence.Patient 1: A 64-year-old man was diagnosed with single-sided definite MD 26 years ago. Between the attacks, he underwent oral therapy with betahistine and an endolymphatic sac surgery 12 years ago. Despite this therapy, there were recurrent attacks of vertigo and hearing loss. In the last few years, there was increasing hearing loss on the side with diagnosed MD (right side). He therefore suffered from functional deafness in this ear and underwent CI, endolymphatic sac surgery revision and occlusion of the lateral SCC .On the left side, there was also moderate hearing loss, especially in the high frequencies with a disturbance up to a 50 dB hearing level between 2 to 6 kHz. The caloric test showed a normal response on the left side but no response on the right side. On both sides, there were no pathological saccades in the video head impulse test.One year after the CI, the patient suffered from new attacks of rotational vertigo. There was no change in the vestibular examinations. An MRI with an ELH sequence was performed, and a cochlear ELH grade 1 was also observed on the left side . Since tPatient 2: A 60-year-old female suffered from rotational vertigo attacks, tinnitus, and increased hearing loss and was diagnosed with definite MD 2 years ago. Functional deafness in that left ear necessitated a CI, endolymphatic sac surgery and an occlusion of the lateral semicircular canal. The right ear showed discreet high-frequency hearing loss of a 30 dB hearing level at 6 kHz. The caloric test showed a normal response on both sides.One year later, the patient presented with vertigo again, and a recovering of the round window membrane and electrode insertion place was performed to exclude a perilymphatic fistula. The pure tone audiometry and the caloric test showed no change.In the following months, there was increasing hearing loss on the right side. Besides the hearing loss, new caloric testing indicated a conspicuous change on the contralateral side too. In the following months, the patient showed further vertigo attacks and new hearing loss on the contralateral ear. An MRI with a hydrops sequence was performed, but no hydrops was demonstrated on the right side .The patient underwent gentamicine topical therapy on the cochlear implanted side (left) to control the vertigo. There were no new attacks after that therapy. Further therapy was not required.Patient 3: A 76-year-old male initially presented with bilateral sensorineural hearing loss at our clinic. There was hearing loss up to a 60 dB hearing level from 0.75 to 4 kHz on the right side. The hearing loss was more severe on the left side. There was only an air conduction threshold, with a decrease from a 70 dB hearing level between 0.25 and 1 kHz to a 95 dB hearing level from 4 to 6 kHz.At this time, the caloric test showed a regular caloric bilateral response, and there were no pathological saccades in the video head impulse test.We performed a CI on his left side. Two months after the implantation, the patient suffered from rotational attacks of vertigo with a spontaneous nystagmus to the opposite ear. These attacks were suspicious for MD because of their duration. The caloric test showed no response at the implanted ear at the time. Furthermore, the head impulse test showed a new abnormality in the right horizontal SCC in comparison to the preoperative testing.It was decided to perform an MRI with a hydrops sequence to exclude an ELH on the unimplanted ear (right side). The MRI with a hydrops sequence, which was performed, presented no hydrops on the right side . The patPatients with severe sensorineural hearing loss as a sequel of MD who do not benefit from a hearing aid are often managed with CI ,30. The One diagnostic challenge in MD patients who have undergone CI is the frequency of bilateral MD ,2,3,4. FIt is known that ELH can also be present on ears. This can be in cases of the uni- and bilateral occurrence of MD ,32,33,34In the unilateral MD, there can also be an ELH in the unaffected ear ,32,33. WIn cases of Bilateral MD, the degree of the ELH is often larger in the ear that was clinically affected first ,35,36. ADifferent MRI sequences are known to detect the ELH in patients with MD . It was For patients with cochlear implants, the MRI behavior is related to the implant magnet artifact and is of particular interest.Recent developments in the implant magnet design , the specific positioning of the implant and the head inside the scanner have made the visual assessment of the IAC, cochlea, SCC and vestibulum possible without complications and without the removal of the magnet ,13,14,15Different publications have shown opportunities for limiting the artifact size by specific sequences (MARS) in patients with cochlear implants and other hearing implants ,20,21,22Our results indicate that, using an ELH-MRI sequence, the ipsilateral side after CI is covered by the implant magnet artifact. This holds true for the axial and coronal plane. For the contralateral side, an estimation of the vestibulum, cochlea and SCC was possible. A grading of the ELH for the vestibular system and the cochlea was performed.We observed one case of cochlear ELH grade 1 and, in two cases, no ELH.This finding shows that a follow-up of the ELH grade in cochlear implantees with MD is useful and can contribute to the evaluation of causes of vertigo after CI in general and specifically for cochlear implantees with MD.In this group, it is of high importance to emphasize that causes for the new occurrence of vertigo after CI can be multifactorial. The possibility of a diagnosis of an ELH for this group of patients with MD is of high importance.One of the limitations of the study is the use of only a single MRI sequence for the estimation of an ELH, which is well established in our radiologic department. We did not use other established sequences  and cannELH MRI allows for the detection of contralateral labyrinthine ELH in cochlear implantees and is a useful diagnostic tool for the postoperative evaluation of vertigo.


This retrospective cross-sectional study assessed older adults aged between 40 and 80 years, registered in the Korean National Health Insurance Service database from 2002 to 2019 to investigate the association between vestibular loss and the risk of dementia. The population was divided into three groups . The hazard ratios (HRs) of dementia in the vestibular and hearing loss groups were calculated using national population data. In total, 2,347,610 individuals were identified . Mean ages were 53.29 years, 58.26 years, and 58.52 years, respectively. Dementia occurred in 127,081 (IR = 4.91 per 1000 person-years), 7705 (IR = 10.79 per 1000 person-years), and 16,116 (IR = 9.63 per 1000 person-years) patients. The vestibular and hearing loss groups had hazard ratios for dementia of 1.084  and 1.074 , respectively, compared with the general group. The results of the current study suggest that vestibular loss increases the risk of developing dementia. Therefore, similar to hearing loss, vestibular loss should be considered a risk factor for dementia, and treatments such as adequate vestibular rehabilitation may reduce this risk. Due to its impact, numerous studies have been conducted to reveal its pathophysiology, and a growing body of literature suggests a potential link between vestibular loss and increased dementia risk5.The vestibular system plays a primary role in sensing head movement and orientation in space. This system projects to numerous parts of the central nervous system, including the cerebellum, brainstem, and cortical areas. Dementia is a broad term referring to severe impairment of memory, language, problem-solving, and other cognitive abilities disrupting daily life. As age demographics shift, dementia constitutes a major public health, social, and economic challenge worldwide and is expected to affect approximately 130 million people by 20506.Previous studies have suggested that the vestibular system is closely related to cognitive functions, especially visuospatial processing11. Another study compared rats with bilateral vestibular lesions to sham animals (preserved vestibular function but removed tympanic membrane). The sham animals had their tympanic membrane removed as rats with bilateral vestibular lesions had the possibility of cochlear injury. The study demonstrated that sham animals performed better on spatial tasks than animals with vestibular lesions11. This suggests that vestibular function is more important than auditory function for spatial memory.Animal studies have demonstrated that vestibular inputs play a role in spatial memory and navigation. Rat studies have shown that bilateral vestibular lesions result in the aberrant activity of the rats’ place cells, which is thought to sustain the brain’s cognitive map of space in the hippocampus13. Other studies have documented that patients with vestibular disorders show impaired spatial memory and navigation, as well as reduced hippocampal volumes14. In addition, there is a higher prevalence of vestibulopathy among people with cognitive loss3.The results of human studies correlated with those of animal studies. Bilateral vestibulopathy is associated with impairment of spatial cognition, immediate memory, processing speed, and executive functionTo our knowledge, no studies have been published on this topic in large-scale populations. This study aimed to investigate the association between vestibular loss and risk of dementia using a large-scale database. In South Korea, the national population is registered with the National Health Insurance Service, and all medical data are organized in the National Health Information Database. Utilizing nationwide data might provide a deeper understanding of this association.Our study included a total of 2,347,610 participants. Of these, 2,145,609 participants were classified into the general control group (those not seeking clinic visits for vestibular or hearing loss), 60,525 participants made up the vestibular loss group, and 141,476 participants were in the hearing loss group. The mean age for each group was 53.29 ± 10.43 years, 58.26 ± 10.76 years, and 58.52 ± 10.91 years, respectively. The other demographic characteristics and detailed information are presented in Table P < 0.001)  in the vestibular loss group and 1.976  in the hearing loss group  in the vestibular loss group and 1.074  in the hearing loss group , designed to assess cognitive function in individuals with hearing loss24. Additionally, another study found that patients with bilateral saccular and semicircular canal vestibular loss had lower scores on the Trail Making Test (TMT) and the Benton Visual Retention Test Part-C (BVRT-C) than the control group, indicating a link between bilateral semicircular canal and saccular vestibular loss and loss of various domains of cognition23. Regarding brain volume, patients with chronic bilateral vestibular loss had a 16.9% decrease in hippocampal volume, a region crucial to various aspects of memory processing12. Conversely, the prevalence of vestibular loss was higher among individuals with cognitive loss3.Our findings suggest that vestibular loss increased the risk of dementia, consistent with the previous studies12. Second, people with vestibular loss often fear falling and feel unsafe, limiting their participation in activities and trips. Consequently, they live a more socially isolated life26. Third, the common-cause hypothesis proposes that both vestibular and cognitive loss are the consequences of a neurodegenerative process. Several factors affect vestibular and cognitive loss, and these risk factors can coexist22.Even though accumulating evidence supports an association between vestibular and cognitive loss, a causal relationship has not yet been validated. Several hypotheses, particularly regarding the association between vestibular loss and Alzheimer's disease, have been suggested. First, vestibular loss reduces the vestibular input to the brain, leading to brain atrophy. A previous study reinforced this hypothesis by demonstrating decreased hippocampal atrophy in individuals with vestibular lossThe present study analyzed the data from over two million individuals and revealed a statistically significant difference in the incidence of dementia between the vestibular loss and general groups Fig. . HoweverThis retrospective study demonstrated that vestibular loss increased the risk of dementia compared to healthy controls, with the HR of dementia being similar to that of the hearing loss group. As the prevalence of dementia is increasing, it is crucial to identify modifiable risk factors. Similar to hearing loss, vestibular loss should be considered an independent risk factor for dementia, and appropriate treatments such as adequate vestibular rehabilitation may reduce this risk. Further studies that include the duration of vestibular loss, severity of symptoms, and the impact of vestibular treatment on cognition are recommended.27. KNHIS collects data such as insurance eligibility, contributions, medical history from enrolled individuals. This public data includes information about demographics such as age and sex, and medication usage such as amount, duration, and date of death28. It also provides detailed health conditions data such as cancer, dementia, and cardiovascular disease, making it the most utilized resource for medical studies. In our study, we used a customized database (DB) from the KNHIS, focusing on sensitive diagnostic codes such as F. After an internal screening process, a customized DB was provided based on the specific variables requested for the study.Korean National Health Insurance Service (KNHIS) is a system in which all Koreans and registered foreigners must enroll31. For eliminating and compare the effect of hearing loss, data on the code of hearing loss were also obtained. We initially selected 5,171,150 participants registered in the KNHIS data from 2002 to 2019. Of these, we selected 3,891,417 participants who had never been diagnosed with vestibular or hearing loss or were diagnosed with these conditions after a dementia diagnosis between 2002 and 2019. After excluding 4352 participants diagnosed with dementia in 2002 or who were not diagnosed with dementia according to the principal diagnostic code, 3,887,065 participants were included in the general population. For cases of vestibular and hearing loss, we selected 941,916 participants diagnosed with either condition between 2002 and 2019. Patients meeting the following criteria were excluded: (1) diagnosed with dementia in 2002, (2) diagnosed with vestibular and hearing loss after 2010, (3) did not meet the criteria for vestibular and hearing loss, (4) diagnosed with both vestibular and hearing loss, (5) diagnosed with dementia but not according to the main code; (6) diagnosed with multiple types of vestibular loss. After excluding 671,889 participants, 77,035 participants with vestibular loss and 192,992 participants with hearing loss remained. From this population, 1,809,482 participants aged < 40 or > 80 years were excluded. Ultimately, we included 2,145,609 participants in the general study population: 60,525 with vestibular loss, and 141,476 with hearing loss. Further details are presented in Fig. For this study, we extracted the International Classification of Diseases, 10th edition codes (ICD-10) for vestibular and hearing loss. The association between hearing loss and dementia has been extensively explored, and hearing loss has been accepted as a risk factor for dementia32. In cases where more than one type of dementia was diagnosed simultaneously, we used the main code in the KNHIS data for definition. We used ICD-10 codes . Detailed definitions and diagnostic codes for vestibular loss, hearing loss, and comorbidities are provided in Supplementary Table We compiled the data using the following variables: age (years), sex, income, and comorbidities such as diabetes, hypertension, dyslipidemia, ischemic heart disease, stroke, and cancer. Additionally, we collected the codes for Alzheimer's dementia, vascular dementia, and other causes of dementia. We included patients who were diagnosed with dementia at least twice and were prescribed medication  to treat the condition at least onceData are presented as the mean ± standard deviation for continuous variables and as n (%) for categorical variables. The t-test was used to compare continuous variables and the chi-square test for categorical variables in baseline characteristics. The Kaplan–Meier survival analysis was applied to assess the cumulative incidence of dementia. Dementia incidence rates (IR) were calculated by dividing the number of dementia cases by 1000 person-years. Furthermore, Cox proportional hazard models were used to compare the risk of dementia after adjusting for demographics and comorbidities such as age, sex, income, diabetes, hypertension, dyslipidemia, ischemic heart disease, stroke, and cancer. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated and a 5% significance level was considered statistically significant. Large dataset collection, exploration, and statistical analyses were conducted using SAS version 9.4 .This study was approved by the Institutional Review Board of the Korea University Ansan Hospital (IRB. No. 2021AS0216). The requirement for informed consent was waived by the ethics committee and the Institutional Review Board of Korea University Ansan Hospital. All methods were performed in accordance with the relevant guidelines and regulations.Supplementary Tables.


CLPP, ERAL1, HARS2, HSD17B4, LARS2, and TWNK genes. All reported cases due to TWNK variants have included neurologic features, such as ataxia and axonal sensorimotor neuropathy.Perrault Syndrome (PRLTS) is a rare, autosomal recessive disorder that presents with bilateral sensorineural hearing loss in all patients and gonadal dysfunction in females. It has been linked to variants in TWNK gene and a diagnosis of Perrault Syndrome was made.A 4.5-year-old female presented to neuromuscular clinic due to ataxia. Neurological examination revealed truncal ataxia and steppage gait, reduced deep tendon reflexes, and axonal sensorimotor polyneuropathy. Auditory brainstem response testing revealed an uncommon type of sensorineural hearing loss known as auditory neuropathy/auditory synaptopathy (AN/AS) affecting both ears. Magnetic Resonance Imaging (MRI) revealed subtle cauda equina enhancement. Nerve conduction studies led to a provisional diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP), and intravenous immune globulin (IVIG) was initiated. The patient was unresponsive to treatment, thus whole exome testing (WES) was conducted in tandem with IVIG weaning. WES revealed a compound heterozygous state with two variants in the Perrault Syndrome should be considered in the differential for children who present with bilateral sensorineural hearing loss, axonal polyneuropathy, and ataxia. Further examination includes testing for ovarian dysgenesis and known PRLTS genetic variants. CLPP, ERAL1, HARS2, HSD17B4, LARS2, and TWNK, all of which are integral in mitochondrial functions [CLPP gene (on chromosome 19q13) encodes a subunit of the ClpP complex, which plays a role in abnormal protein breakdown in the mitochondria [ERAL1 gene (on chromosome 17q11) encodes a GTPase protein, important for proper assembly of the mitochondrial ribosome [HARS2 (on chromosome 5q31) and LARS2 genes (on chromosome 3p21) are involved in translation of mitochondrial proteins [HSD17B4 gene (chromosome 5q23) is involved in beta-oxidation of fatty acids and steroid metabolism [TWNK (on chromosome 10q24) encodes the Twinkle protein, which is a mitochondrial DNA helicase and is required for mtDNA replication [Perrault syndrome (PRLTS) is a rare autosomal recessive disorder, with approximately 100 affected individuals reported. These individuals present with bilateral sensorineural hearing loss (SNHL), while females  also present with ovarian dysfunction . Most calication . This geCLPP and LARS2 variants have presented with or without neurologic features, while reported cases of PRLTS due to TWNK variants always include neurologic features [TWNK-related PRLTS cases include nystagmus, positive Romberg sign, ataxic gait, reduced deep tendon reflexes in lower limbs, pes cavus, and an axonal sensorimotor neuropathy [TWNK variants, onset of symptoms can range from < 3–48 years old [TWNK gene variants, review previously published TWNK-associated PRLTS cases, and highlight the clinical overlap between PRLTS and other neuropathies.Reported cases of PRLTS associated with uropathy . Of the ears old , 9–16. BTWNK gene (NM_021830.4): c. 561_563dupTGA, p.Asp188dup in exon 1 and c.1909 C > T, p.Arg637Trp in exon 5. Family studies showed that the patient inherited the p.Asp188dup variant from mother and the p.Arg637Trp variant from father. Both parents were unaffected.A 4.5-year-old female presented to the neuromuscular clinic at Ann & Robert H. Lurie Children’s Hospital in Chicago with an abnormal gait. She was born at 37 weeks gestation in a non-consanguineous union to parents of Asian descent, without any pregnancy or delivery complications. She has a healthy 12-year-old sister. She had an age-appropriate developmental trajectory in the first year of her life. She had an upper respiratory illness at 10 months age during a visit to China after which the parents noted that she slowed down in her motor developmental trajectory. Parents’ concern was deepened when they noticed an unsteady gait after she started walking at 16 months of age. She could walk and run but would appear unsteady, leading to occasional falls. Toe walking was noted at 2 years of age, in addition to a steppage gait. Around 3 years of age she had a viral illness, after which she was noted to be more unsteady, resulting in at least 2 falls per week. Parents reported they had no concerns about speech and language development, and she was able to answer questions and follow direction in English and Mandarin until age 3.5 years. At that point she stopped responding to her name and music, following verbal instructions, and speech began to regress. Family history was non-contributory. Her weight was at the 43rd and height at 29th percentile for age. Exam was notable for a cooperative child who was inconsistent following commands, with a limited verbal output for age. There was no note of scoliosis or joint hyperextensibility and the cardiac, pulmonary, gastrointestinal exams were normal. She recognized mother and was able to point to her nose inconsistently on command. Auditory exam demonstrated inconsistencies in hearing. Extraocular movements were full and there was no nystagmus. Fundus exam did not reveal any abnormalities. The rest of the cranial nerve exam was normal. Muscle bulk was typical for age and there was absence of muscle atrophy. She had mild tightness in bilateral heel cords but otherwise tone was normal in other areas. Strength examination was limited due to cooperation, but within the limitations she was noted to have difficulty with bilateral foot eversion (4-/5) and demonstrated good power in the rest of the muscles of the face, neck, trunk, upper and lower extremities. Deep tendon reflexes were absent at the ankles and knees bilaterally and were 1 + at the other sites. She had normal coordination in her upper extremities but demonstrated a wide based, unstable and steppage quality when walking. Her Romberg’s testing was negative, suggesting that she had a form of sensory ataxia. An electromyography (EMG) and nerve conduction study demonstrated absent upper  and lower extremity  sensory responses with sparing of the sural sensory response. There was a severe decrease in lower extremity compound muscle action potential (CMAP) amplitudes in the nerves of lower extremity  and mild decrease in the upper extremity (median and ulnar) with normal distal latency and conduction velocities. F wave was absent in the tibial nerve. EMG demonstrated a neurogenic pattern with increased duration of voluntary motor unit potentials in the tibialis anterior and the gastrocnemius muscles. The overall picture was suggestive of a chronic axonal sensorimotor polyneuropathy. Auditory brainstem response testing was consistent with bilateral auditory neuropathy/auditory synaptopathy , hearing loss characterized by abnormal synchronization of neuronal responses to sound at the level of the auditory nerve and brainstem. Behavioral auditory evaluation of thresholds revealed profound loss. MRI of the spine (at age 4.5 years) was notable for subtle cauda equina enhancement. MRI of the brain (at age 4.5 years), internal auditory canals and cochleae was unremarkable. Creatine kinase, lactate, and cerebrospinal fluid (CSF) studies were all within normal limits. A comprehensive neuropathy panel and frataxin repeats testing was normal. On a subsequent visit she was noted to be more unsteady and, per parents, falling more frequently. IVIG was initiated, with a provisional diagnosis of CIDP based on history and cauda equina enhancement on imaging. Audiology assessments confirmed profound hearing loss and cochlear implant candidacy evaluation was initiated. She received 3 initial doses of IVIG and her parents noted slight improvement in gait. Thus, treatment was increased to every 2 weeks for 3 treatments, followed by every 3 weeks for 3 treatments. Further clinically significant improvement was not observed. Therefore, a whole exome testing (WES) was sent while IVIG weaning was initiated. WES, performed at GeneDx, Inc. using the next generation sequencing on an Ilumina platform, revealed a compound heterozygous state with two variants in the She underwent cochlear implantation and began a program of intensive auditory and spoken language habilitation. Sound detection thresholds improved to the normal range in both ears. However, improvement in measurable word recognition skills and spoken language were slow to develop and remained limited after one year of implant experience. Such slow progress is not typical of implanted children with a history of auditory experience and spoken language, including those with auditory neuropathy.TWNK gene variants can also cause ovarian dysfunction, further testing was done. Follicle stimulating hormone (FSH) level was 15.8 mIU/ml (reference range 1–5 mIU/ml), with normal luteinizing hormone (LH), creatine kinase (CK), and lactate levels. Ultrasound (US) of the pelvis was significant for an absence of ovarian structures. Based on the results of the clinical features of ataxia, bilateral sensorineural hearing loss, axonal sensorimotor polyneuropathy, WES results, FSH levels, and US of the pelvis, a diagnosis of PRLTS was made.Since PRLTS due to TWNK gene. Our patient presented with ataxia at 16 months of age, making her onset of neurological features the youngest of all reported TWNK-associated PRLTS cases to date (Table TWNK gene, IVIG was weaned off, as there is no available evidence that IVIG is effective in treating PRLTS.We report a case of early-onset ataxia, axonal polyneuropathy, and bilateral auditory neuropathy/auditory synaptopathy, an uncommon type of sensorineural hearing loss, associated with PRLTS attributed to compound heterozygous variants in the About 15% of children identified with hearing loss following referral from newborn hearing screening have auditory neuropathy/auditory synaptopathy , 18. ItsTWNK-related PRLTS had nystagmus, pes cavus, and a positive Romberg test (Table Although most reported cases of st Table , these fTWNK-related PRLTS to CIDP and Friedreich’s Ataxia, all of which can present with sensorimotor neuropathy, ataxia, and reduced to absent deep tendon reflexes. PRLTS due to TWNK variants and Friedreich’s Ataxia can additionally present with nystagmus and sensorineural hearing loss, which is rare in CIDP. However, only TWNK-related PRLTS commonly presents with gonadal dysfunction. Thus, we suggest that children who present with the clinical signs of ataxia and polyneuropathy should not only be evaluated for CIDP and Friedreich’s Ataxia, but also for PRLTS, specifically evaluating gonadal function in females and genetic testing for known variants. Additionally, when considering these differential diagnoses, careful attention should be paid to the presence of sensorineural hearing loss and CSF findings. As previously discussed, CIDP rarely presents with sensorineural hearing loss. CIDP additionally presents with elevated CSF protein in most cases, whereas our patient’s CSF findings were all within normal limits. Thus, the presence of sensorineural hearing loss and normal CSF protein supports the diagnosis of PRLTS versus an acquired neuropathy, such as CIDP.Table Genetic testing for our patient demonstrated two variants Table . The p.ATWNK variants demonstrate significant neurological deficits, yet not all previous case reports have included comprehensive neurological examinations in their findings [Previously reported literature and our case shows a predominance of females, although the inheritance is autosomal recessive. We postulate that this could be due to an increased recognition of PRLTS in females with ovarian dysfunction, adding to the phenotype of sensorineural hearing loss and ataxia. It has been claimed that PRLTS is not as rare as would be expected from the paucity of reported cases , 11. Thifindings . We suggfindings , 25.Finally, based on the natural history of our patient, we recommend that female children presenting with axonal polyneuropathy and ataxia should be evaluated for ovarian dysgenesis and genetic testing for PRLTS should be considered.