In this study, localization accuracy and sensitivity to acoustic interaural time differences (ITDs) in subjects using cochlear implants with combined electric-acoustic stimulation (EAS) were assessed and compared with the results of a normal hearing control group.Eight CI users with EAS  and symmetric binaural acoustic hearing and 24 normal hearing subjects participated in the study. The first experiment determined mean localization error (MLE) for different angles of sound incidence between ± 60° . The stimuli were either low-pass, high-pass or broadband noise bursts. In a second experiment, just noticeable differences (JND) of ITDs were measured for pure tones of 125 Hz, 250 Hz and 500 Hz (headphone presentation).Experiment 1: MLE of EAS subjects was 8.5°, 14.3° and 14.7°, . In the control group, MLE was 1.8° (broadband stimuli). In the differentiation between sound incidence from front and back, EAS subjects performed on chance level. Experiment 2: The JND-ITDs were 88.7 μs for 125 Hz, 48.8 μs for 250 Hz and 52.9 μs for 500 Hz (EAS subjects). Compared to the control group, JND-ITD for 125 Hz was on the same level of performance. No statistically significant correlation was found between MLE and JND-ITD in the EAS cohort.Near to normal ITD sensitivity in the lower frequency acoustic hearing was demonstrated in a cohort of EAS users. However, in an acoustic localization task, the majority of the subjects did not reached the level of accuracy of normal hearing. Presumably, signal processing time delay differences between devices used on both sides are deteriorating the transfer of precise binaural timing cues. Accurate localization of sound incidence is of utmost importance to prevent potential dangerous situations in everyday life (e.g. traffic situations). Furthermore, acoustic localization supports auditory scene analysis and improves speech perception e.g. in noisy environments. Interaural time differences (ITDs) and interaural level differences (ILDs) are the most relevant cues for the localization of sound sources. Normal hearing persons (NH) are most sensitive for ILD cues in higher frequencies above 1.5 kHz, whereas ITDs are relevant for sound localization of signals with lower frequencies, explored by e.g. Blauert in 1997 , 3. UnleFor users of cochlear implants (CIs), sound localization and speech perception in noise is still a challenging task. This applies in particular to communication situations in noisy environments. Studies have shown that some CI users are sensitive to ITD cues measured in psychoacoustic setups, such as with simultaneous CI stimulation and contralateral acoustic stimulation , 8. FurtOne potential reason for deteriorated binaural cue sensitivity is the lack of binaural synchronization in unilateral CI users with contralateral hearing aid or normal hearing. Electric stimulation of the auditory nerve using a cochlear implant is potentially faster compared to acoustic stimulation with slower acoustic travelling wave . In addiIn 2014 Jones et al. hypothesized that the lack of localization performances in bilaterally implanted CI users is probably caused by CI programming strategies and is not the result of neural impairment of central areas [For patients with substantial residual hearing in the lower frequency range but poor speech perception, implantation of a CI with hearing preservation (soft surgery procedure) enables combined electric-acoustic stimulation (EAS) to provide enhanced hearing and restore speech perception . The firOnly a small number of studies investigated acoustic ITD sensitivity in EAS users so far , 29. TheEight CI recipients with hearing preservation in the implanted ear  and 24 NH  took part in the study. The inclusion criterion for the NH group was sufficient hearing with thresholds better than 30 dB HL in all frequencies between 250 Hz and 8 kHz. Demographical data of the EAS group is shown in MED-EL  devices were used in all EAS participants. Used electrodes were Flex20 and Flex24 see in  which weAll subjects gave their written consent for participation in this study. The study was approved by the local institutional review board . The tests were conducted in accordance with the Code of Ethics of the World Medical Association (Declaration of Helsinki) for experiments with humans. All participants were offered breaks from time to time to achieve consistent results.The mean localization error (MLE) in the horizontal plane was determined in a free field setup (anechoic chamber). The setup used was firstly described by Weißgerber et al. in 2014 . A multiThe stimuli were five noise bursts with a burst length of 30 ms (3 ms ramping) followed by a pause of 70 ms. Three different noise signals were tested for the EAS group: a low-pass (LP) noise , a high-pass (HP) noise  and a broadband (BB) white noise. The NH group was only tested with the broadband noise. The stimuli were presented at a level of 65 dB SPL with randomized level roving of ± 6 dB in steps of 3 dB to avoid use of monaural intensity cues. For each test angle the localization error was calculated as the difference between perceived and presented angle averaged (median) over the five measurements. The frontal and dorsal MLE was calculated as the localization error averaged over all frontal or dorsal test angles.JND-ITDs were measured using a two-alternative forced choice method (2-AFC) with a 1 up-2 down procedure to estimate the threshold of 70.7% correct . The tesThe stimuli were presented dichotically via headphones  to residual acoustic hearing without additional hearing supplies. An USB audio interface RME Fireface UC  was used for digital to analog conversion and as a headphone amplifier. In this setup also the software MATLAB R2010a  was used to generate and present the sound stimuli and to record the patient’s response. The sound pressure level was 65 dB SPL for the NH group. In the EAS group, interaural loudness matching to consolidate symmetrical loudness perception on both sides was performed for each test frequency prior to the experiment. For this purpose, pure tone pulses were first presented to the one ear with better low-frequency hearing and the test person was asked to adjust a comfortable loudness level. Afterwards, subjects were asked to adjust the loudness of the other (poorer hearing) ear to elicit the binaural impression of a centered stimulus location inside the head. This procedure was repeated five times and the mean sound pressure level was chosen as presentation level for the stimuli in the study. This was done to achieve an ILD of zero for the ITD experiment. The stimulation levels are listed in Two consecutive sound signals with opposing ITDs on each side and a pause of 400 ms between the signals were presented. The subjects were asked to indicate the change in the perceived sound position by choosing between two arrows pointing left or right on a graphical user interface on a tablet. The order of the signals with opposing ITDs was randomized. The method was adapted from earlier works by Gifford et al . For traThe EAS group repeated the test three times for each frequency. The NH group performed one iteration per frequency. The JND-ITDs in the EAS group were calculated as the mean of the three trials for each frequency. The order of the frequencies was randomly chosen to avoid any bias caused by training effects .For descriptive statistics, boxplots and the description of median values were used throughout the manuscript. Nonparametric tests were used for statistical analysis of MLE and ITD sensitivity. For pairwise comparison of subject groups, the Mann-Whitney-U-test was used to compare the results of the EAS cohort with those of the NH group. The Wilcoxon signed rank test with adjustment of alpha (Bonferroni correction) was used for tests of paired samples within the subject groups. The tests comparing more than two related samples were performed using Friedman’s test . Correlations were tested via Spearman rank correlation. A p-value < 0.050 was considered significant. IBM SPSS Statistics 24  was used for the analysis.low-pass: z = -1.752, p = 0.08; high-pass: z = -0.420, p = 0.674; broadband: z = -0.700, p = 0.484). Therefore, further analysis were only conducted for the frontal condition. The MLE of the individual NH subjects is found in The individual accuracy of localization for the EAS cohort for the three bandpass stimuli are depicted in z = -4.186, p < 0.001). In the EAS group, there was no significant impact of the spectral characteristics of the test stimuli on MLE .The MLE  for broadband stimuli was 1.8° for the NH group. In the EAS group an average MLE of 8.5° was found for low-pass signals, 14.3° for high-pass signals and 14.7° for broadband signals, respectively. Boxplots of the MLE are shown for both groups in Individual JND-ITD for the EAS subjects as well as median JND-ITD for the NH are depicted in df = 2, χ = 4.750, p = 0.093). In the NH group, the JND-ITDs differed significantly depending on test stimulus frequency . A pairwise comparison revealed a significant difference in JND-ITDs for 125 Hz compared with the other two test frequencies, but no significant difference between the JND-ITDs of 250 Hz and 500 Hz was found . Boxplots of both groups for the different test frequencies are plotted in z = -0.610, p = 0.564). The results of the JND-ITD at 250 Hz and 500 Hz differed significantly between subject groups .In the EAS group, there was no impact of test stimulus frequency on JND , whereas there were no significant correlations between interaural asymmetry and the JND-ITDs for 125 Hz and 250 Hz .The interaural asymmetry of pure tone audiogram thresholds at 500 Hz correlated significantly with the JND-ITD of 500 Hz for the EAS subjects .A significant correlation was found between the mean of pure tone audiogram thresholds and the JND-ITDs for 125 Hz and for 250 Hz but not for 500 Hz . No age effects were found in nearly all MLE and JND-ITD results .The NH group was significantly younger than the EAS group (No correlations were found in the EAS group between the speech perception (Freiburg monosyllable speech test) or the EAS experience and the measured MLE  and the JND-ITDs . The MLE of LP signals did not correlate significantly with the JND-ITDs .Eight CI users with EAS  and 24 NH subjects underwent evaluation of MLE  and ITD sensitivity . All EAS subjects were able to localize sounds. However, the EAS group showed decreased localization accuracy compared to the NH group. The MLE range for broadband signals for EAS users varied from 5.5° to 18.7° (NH range: 0.8° to 5.2°). The EAS user with the best performance achieved a MLE of 3.6° for the low-pass signals, reaching the range of subjects with normal hearing. EAS users could not distinguish between a frontal and a dorsal sound presentation with a mean amount of front/back confusions at chance level. EAS users were able to detect ITDs in different low-frequency sinusoids . ITD sensitivity was well below the physiological threshold of around 700 μs, with the exception of two subjects who reached JND-ITDs above this threshold at two different test frequencies .The MLE of low-pass stimuli for EAS users is slightly (not significant) better compared to high-pass and broadband stimuli. But the assumption of improved localization accuracy  for low-pass signals compared to high-pass signals could not be confirmed, although they are sensitive to acoustic ITDs in the lower frequencies. ITD sensitivity was not significantly different for 125 Hz between the EAS cohort and the NH group, where the interaural asymmetry of pure tone thresholds was the slightest and the pure tone audiogram thresholds were the lowest.Comparing different groups of CI users, EAS users demonstrated nearly equal sound localization accuracy for broadband stimuli compared to a cohort of patients with single-sided deafness  . BimodalA comparison of study results on sound localization accuracy is only possible to a certain extent, since differences in methodological issues have an effect on the study outcome. The experimental setup in Gifford et al.  compriseFurthermore, differences in the angular resolution of response recording lead to differences in chance level. In the study of Gifford and collaborators  nine louThe assessment of sound localization accuracy may also depend on characteristics of the stimulus. The present setup was resembling the procedure described by Seeber , and appFinally, differences in study subjects presumably could explain diverging results. The minimum EAS experience of test subjects reported by Gifford and colleagues was 6 months with an average experience of 3.5 years, whereas the minimum experience in the present study was 12 months. However, mean EAS experience of 3.6 years was similar.The JND-ITDs for the low-frequency signal (125 Hz) in EAS users and in the NH control group are at a comparable level. One EAS user showed a remarkable JND-ITD of only 27.2 μs at 125 Hz. The present results indicate that ITD sensitivity for lower frequencies is not affected in the EAS users studied here. This finding is potentially the consequence of near to normal hearing thresholds and therefore small or absent interaural asymmetry in the lower frequency range. Correspondingly significant correlations were found between the mean pure tone audiogram thresholds and the JND-ITDs for 125 Hz and 250 Hz in the EAS subjects. For the stimulus frequency of 500 Hz, at which residual hearing is worse and interaural asymmetry is larger, the JND-ITDs correlated significantly with interaural asymmetry of pure tone audiogram thresholds (but not mean pure tone audiogram thresholds). The larger interaural asymmetry is potentially the reason for the significant difference in JND-ITD between the EAS cohort and the NH group for higher test frequencies. A dependence of binaural cue sensitivity on a small interaural asymmetry of the pure tone thresholds was also reported by Loiselle et al. . In theiOn the other hand, it was assumed that the position of the electrode inside the scala tympani potentially increases the stiffness of the basilar membrane, and therefore distorts the transmission of the traveling wave. This study showed that EAS subjects can perceive very small JND-ITDs below 100 μs at lower frequencies. Thus, it can be assumed that an undistorted acoustic low-frequency hearing with precise timing in the cochlear is possible even with an inserted electrode array.No significant correlation was found between MLE and ITD sensitivity for any of the frequencies tested in the JND-ITD setup. Similar to previous studies, it was assumed that the ability to detect ITDs leads to improved localization accuracy, especially for low-pass filtered signals .It has to be considered that the cohort of EAS users of the present study was rather small. In addition, the device delivering acoustic amplification was varying between subjects . This heterogeneity might disguise potential correlations between accuracy of localization and JND-ITDs, since accuracy was measured with different modes of amplification, while JND-ITD was determined with headphone presentation of stimuli. The delay introduced by signal processing in the hearing aid  achieved the best localization accuracy within the EAS group . However, the other participant (P1) demonstrated poorer MLE (15° for broadband stimuli) but better JND-ITDs . The considerable discrepancies in localization accuracy could be associated with the difference in the development of hearing impairment in these two study participants . It can be assumed that early hearing loss prevents the development of accurate processing of complex binaural information, caused by insufficient transfer of binaural cues. Furthermore, the delay between the first and second ear CI provision is potentially confounding  as it was shown in children that a longer inter-implant interval decreased localization accuracy [CI EAS users with sufficient bilateral hearing in the low-frequency range are able to detect acoustic ITDs with thresholds close to normal hearing. In an acoustic localization task, however, the accuracy of normal hearing was not achieved and the detection of front/back sound incidence was on chance level. The transmission of accurate binaural time information by the devices used for acoustic amplification on both sides should be ensured in the future.S1 Table(XLSX)Click here for additional data file.S2 Table(XLSX)Click here for additional data file.S1 Figst row), high-pass (2nd row) and broadband (3rd row) filtered signals. Stimuli include compensation of individual loudspeaker frequency response. Plots of frequency responses were smoothed for better readability.Stimuli of the frontal loudspeaker (located at -2°) for the low-pass (1(TIF)Click here for additional data file.


Hearing loss is the second most common nonfatal problem affecting the Chinese population. Historical studies have suggested an association between exposure to heavy metals, such as cadmium and lead, and hearing loss. Few studies have investigated this relationship in the general population in China. We conducted a case-control study with 1008 pairs of participants from a cross-sectional epidemiological survey conducted in Zhejiang Province. A self-designed questionnaire was adopted to collect information on demographics, chronic diseases, lifestyles and environmental noise. Pure-tone averages of hearing thresholds at frequencies of 0.5, 1, 2, and 4 kHz were computed. Blood lead and cadmium levels were analyzed with an atomic absorption spectrometer. After adjusting for all other potential confounding factors, compared with the lowest blood cadmium quartile (0.00–0.53 μg/L), blood cadmium quartile 2 (0.54–0.92 μg/L), quartile 3 (0.93–1.62 μg/L) and quartile 4 (1.63–57.81 μg/L) exhibited significantly elevated risks for hearing loss, with odds ratios of 1.932 (95% CI: 1.356–2.751), 2.036 (95% CI: 1.423–2.914) and 1.495 (95% CI: 1.048–2.133), respectively (P-trend<0.001). However, an association of lead with hearing loss was not found. Young age (less than 60 years), male sex and current smoking were associated with increased blood cadmium concentration. Additionally, a positive association between blood cadmium and lead concentrations was found. Therefore, we conclude that exposure to environmental cadmium may be a risk factor for hearing loss among the general population in China. Hearing loss is a critical global public health issue . CurrentOtotoxicants, such as heavy metals, organochlorines and drugs, are substances that can induce damage to the structures and nervous system of the inner ear . HistoriTo date, no scientific studies have shown beneficial effects of lead or cadmium on human physiological health, which means that their ideal content in the human body is zero owing to their harmfulness . TherefoIn the 25-year Global Burden of Disease study, hearing loss was the second most common nonfatal problem affecting the quality of life of the Chinese population . The curPreviously, a large study population was enrolled using a multistage stratified cluster random sampling method in Zhejiang Province from 2016 to 2018. Six cities  were randomly selected by stratifying according to geographical distribution and city sizes, based on the national nutrition and health survey in Zhejiang in 2012. Then, one healthcare center was randomly selected in each city, and with the coordination of local medical staff, all the participants in each healthcare center were recruited and selected by cluster sampling if they met the inclusion criteria: 1) local residents (living in the area for more than 12 months); 2) workplace noise exposure that did not meet the national noise pollution standards (less than 85 dB); 3) no previous medical history of craniocerebral injury, history of ototoxic drugs or detonation deafness; and (4) no history of inflammation or fever within 30 days before the hearing test. From the large study population, 2016 participants (1008 pairs) were selected for the present case-control study with a 1:1 paired design, and the matching criteria included age (within one year), sex, and residence cities. In the case group, participants had hearing loss while in the control group participants had normal hearing.Audiometry examinations were performed by trained technicians in a sound-proof chamber with noise levels below 30 dB. The devices utilized in this research were an audiometer  and standard headphones . Pure-tone air conduction hearing thresholds were tested in both ears of the participants at frequencies of 0.5, 1, 2, and 4 kHz over an intensity range of -10 to 110 dB. In the audiometric examination, participants who did not respond at least once were considered nonresponsive. To measure the reliability of participants’ responses, the 1 kHz frequency was tested twice in either ear. It was considered an unreliable response if the results differed by more than 10 dB. Finally, we computed the pure-tone average (PTA) at frequencies of 0.5, 1, 2 and 4 kHz, and hearing loss was defined as PTA >25 dB (HL) in either ear .Blood samples for lead and cadmium measurements were collected into trace-metal-free ethylenediaminetetraacetic acid tubes, and specimens were immediately transferred at 2–8°C to a central laboratory for analysis . Lead and cadmium concentrations in venous whole blood were measured using graphite furnace atomic absorption spectrometry . For internal quality assurance and control, commercial standard reference materials (Whole Blood Lead Control (nos. 20162400100) and Cadmium Control (nos. 20162400101)) were obtained from Beijing BOHUI Innovation Biotechnology Co., Ltd. Beijing, China. Interassay coefficients of variation ranged from 2.23% to 5.98% for blood lead quality control pools and from 3.45% to 6.07% for blood cadmium quality control pools.A pilot survey was carried out with an initial version of the questionnaire for validation and improvement, and then the validated questionnaire was used for the formal survey. Prior to the questionnaire survey, investigators received professional training to ensure data collection quality. The information in the questionnaire included demographic information , chronic diseases , lifestyle factors , and environmental noise . Participants were classified as never smokers, secondhand smokers, former smokers, or current smokers. Alcohol consumption was classified as never, former, and current. Hypertension, diabetes, hyperlipidemia, otitis media, migraine, and anemia were classified based on a self-reported physician diagnosis.If a participant indicated exposure to loud noise in the workplace at least once a week, then the participant was considered to have workplace noise exposure. If the participant had been exposed to loud noise outside of work  at least once a week, then the participants were considered to have been exposed to recreational noise. To emphasize an important point, the volume of the noise was the subjective feeling of the participant, so if a participant felt that the sound was too loud to feel uncomfortable, then he/she was considered to have been exposed to loud noise. The database was established using Epidata 3.0, and analyses were performed using SPSS 22.0 for Windows . A paired t-test was performed to compare the differences in the means of age, hearing threshold, and concentration of logarithmic transformed lead and cadmium levels between the case and control groups. Paired chi-square tests were used to analyze the distribution of sex, marital status, educational background, household monthly income, smoking, alcohol consumption, fruit and vegetable intake, environmental noise, chronic diseases and ear diseases between the case and control groups. Because the blood lead and cadmium contents were not normally distributed, logarithmic transformation was performed to normalize their distributions. Multivariate conditional logistic regression was used to analyze the relationship of lead, cadmium and other variables with hearing loss. Multiple linear regression was conducted to determine how all of the variables affect blood cadmium concentration.All subjects gave their informed consent for inclusion before they participated in the study. The study was conducted in accordance with the Declaration of Helsinki, and the protocol was approved by the Ethics Committee of Hangzhou Normal University (No. 2017LL107).The differences in the participants’ characteristics between the case group and control group are illustrated in The logarithmic-transformed levels of blood lead showed no significant differences between the case group (1.58±0.17 μg/dL) and control group (1.57±0.16 μg/dL). The logarithmic-transformed levels of blood cadmium were significantly higher in the case group (0.34 ± 0.24 μg/L) than the control group (0.32 ± 0.22 μg/L) (P <0.05). The PTAs of hearing thresholds were significantly higher in the case group (38.21±12.91 dB) than in the control group (18.68±4.93 dB).Between the case group and control group, participants showed significant differences in lifestyle-related factors such as smoking, alcohol consumption, and daily fruit and vegetable intake. Regarding disease-related factors, hypertension, hyperlipidemia, diabetes, otitis media, migraine, and anemia were significantly associated with hearing loss. We also analyzed the correlation between environmental noise and hearing loss, and the results showed that workplace noise was significantly associated with hearing loss, but recreational noise was not.The associations of participants’ blood cadmium and lead levels with hearing loss in all models are displayed in The influencing factors of blood cadmium content in Chinese residents were also analyzed. As shown in Many experimental studies have shown the harmful effects of lead and cadmium on hearing functions. The cochlear component of hearing is more vulnerable to cadmium toxicity than other parts of the auditory system . CadmiumAfter adjusting for other variables, we did not find an association between blood lead and hearing loss. In the present study, the lead concentration ranged from 1.50 to 16.50 μg/dL. Similarly, in 2,535 American adolescents, Josef et al. found that blood lead exposure was not associated with low-frequency hearing loss , and the lead concentration range was within 2 μg/dL . Choi etOur findings showed that increased blood cadmium could elevate the risk for hearing loss in Chinese adults. Compared with the first quartile of blood cadmium, the risk for hearing loss increased in the second and third quartiles but decreased in the fourth quartile, showing an inverse U pattern. This result is different from the findings of previous studies; Choi et al. also found a positive relationship of blood cadmium with hearing loss in the American general population, but the risk for hearing loss was consistently increased with the increase in cadmium concentration . After aIn this research, current smoking and lead exposure showed an association with blood cadmium. Cadmium typically enters the body from contaminated food, such as vegetables, grain, and shellfish; water; polluted air, and pollutants emitted during metal smelting and refining, and the production of batteries, alloys, pigments and plastic stabilizers , 24. SimIn China, the number of smokers exceeds 300 million, and 740 million nonsmokers are exposed to secondhand smoke . In our The current study has several strengths. Above all, this study first examined the relationship between blood lead and cadmium levels and hearing loss in a large general Chinese population, rather than focusing on occupational workers or animals. Second, we performed case-control analysis matched for age, sex and residence cities, which can exclude the influences of these factors. For the nonoccupational population, age proved to be the main influential factor for hearing loss . Third, Nonetheless, this study had some limitations. This was a case-control study, and causal relationships between heavy metals and hearing loss cannot be inferred. Second, occupational noise and recreational noise information were obtained from self-reporting, which probably caused potential misclassification. Third, pure-tone air conduction hearing threshold testing was used for hearing loss detection, but some hearing loss caused by nerve conduction latency problems adversely affected by lead and cadmium exposure may need to be detected using a more sensitive method, such as auditory brainstem response (ABR) testing. Last, propensity score matching is a great method for decreasing bias, and this case-control study would have been better if the controls and the cases were matched with this method to include additional factors, such as noise exposure.In summary, the present analysis of a well-defined representative sample of Chinese adults found a statistically significant association between current exposure to environmental cadmium and the risk of hearing loss, independent of known risk factors including various types of noise exposures or clinical risk factors. However, we found no significant association between environmental lead exposure and hearing loss in adults. Our findings indicate that knowledge of cadmium exposure may allow for earlier interventions in the public health community and that the government should make efforts to reduce environmental lead and cadmium exposures and conduct interventions for related lifestyles, such as tobacco control, to prevent hearing loss in the general population. Further studies with prospective designs and wide ranges of exposure are needed to confirm the results due to concerns related to causal inferences and potential reverse causality.S1 Table(DOCX)Click here for additional data file.S1 File(SAV)Click here for additional data file.


Hearing impairment is a neurological symptom of hypophosphatasia (HPP), which leads to a reduced quality of life. However, the pathomechanism of hearing impairment and the effects of asfotase alfa enzyme replacement therapy on hearing function in HPP have not been clarified. Here we report a case and present clinical data of a patient with perinatal HPP whose hearing impairment improved after asfotase alfa treatment. Asfotase alfa administration, enzyme replacement therapy, improves the symptoms of HPP, such as bone mineralization, growth, respiratory function, and mobility, and significantly improves survival rate [Hypophosphatasia  level at 12 IU/L (reference range: 530–1610 IU/L) and a slightly increased corrected serum calcium level of 11.8 mg/dL (reference range: 8.8–11.3 mg/dL). Urinary calcium/urinary creatinine ratio was 0.43 mg/mg (reference range: < 0.21 mg/mg). His parents were asymptomatic; however, both also had low serum ALP levels ). Owing to the clinical manifestations, examination results, and family history, the patient was clinically diagnosed as having perinatal lethal HPP. Subsequently, genetic analysis of the ALPL gene was performed after obtaining informed consent from the parents. Sanger sequencing identified compound heterozygous variants in the ALPL including the previously reported pathogenic variants c.1559delT (p.Leu520Argfs) and c.1276G > A (p.Gly426Ser) (NM_000478.5) [A Japanese boy showed intrauterine growth restriction and shortened bones of the extremities on echocardiography during gestation. He was born at 38 weeks of gestation by planned cesarean section. His birth weight was 2465 g (−0.8 SD), height was 45.0 cm (−2.0 SD), chest circumference was 29.9 cm (−0.9 SD), and head circumference was 32.2 cm (−0.8 SD). He was admitted to the Neonatal Intensive Care Unit soon after birth with respiratory distress syndrome. X-ray displayed thin ribs with poor ossification, shortening of the long tubular bones, and poor cranial bone formation. He had a narrow chest, due to the skeletal malformation, which caused respiratory failure and tracheobronchomalacia (TBM). He was sedated and put on mechanical ventilation with a high peak inspiratory pressure of 20–25 cmHAudiological evaluation was carried out several times over the course of therapy. Hearing impairment improved after asofotase alfa administration. Initial evaluation of the auditory brainstem response at 6 years demonstrated that there was no response in the right ear, and that waves III and IV were detected at 150 dB in the left ear. The patient was diagnosed as having profound hearing impairment. He was re-evaluated by behavioral observation audiometry and visual reinforcement audiometry at the age of 8 years. On behavioral observation audiometry, he did not respond to 80 dB sounds, nor loud sounds of a drum. Visual reinforcement audiometry demonstrated improvement of his hearing capacity. Following these results, he started using hearing aids at 8 years of age. His hearing ability gradually improved, and he began to respond to sounds without hearing aids. More babbling was observed, and it appeared that he could understand simple words  together with gestures. The most recent evaluation with visual reinforcement audiometry at the age of 10 years demonstrated mild hearing impairment, which was a significant improvement of the hearing capacity from profound hearing impairment at the initial evaluation .Fig. 1Au3The pathology of hearing impairment in HPP is not well understood. One study has reported defects on bones that are thought to be associated with HPP. Okazaki et al.  reportedInfants and young children show rapid and substantial improvements in skeletal mineralization, followed by improvements in respiratory, motor, and cognitive function after 1 year of treatment with asfotase alfa . Our patThis research did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors.There is no conflict of interest.


Hearing loss is a disabling condition that increases with age and has been linked to difficulties in walking and increased risk of falls. The purpose of this study is to investigate changes in gait parameters associated with hearing loss in a group of older adults aged 60 or greater. Custom-engineered footwear was used to collect spatiotemporal gait data in an outpatient clinical setting. Multivariable linear regression was used to determine the relationship between spatiotemporal gait parameters and high and low frequency hearing thresholds of the poorer hearing ear, the left ear, and the right ear, respectively, adjusting for age, sex, race/ethnicity, and the Dizziness Handicap Inventory–Screening version score. Worsening high and low frequency hearing thresholds were associated with increased variability in double support period. Effects persisted after adjusting for the effects of age and perceived vestibular disability and were greater for increases in hearing thresholds for the right ear compared to the left ear. These findings illustrate the importance of auditory feedback for balance and coordination and may suggest a right ear advantage for the influence of auditory feedback on gait. Hearing loss is a disabling condition that increases with age and affects nearly two-thirds of adults aged 70 and over in the US population . Among oFalls are increasingly common with age, with more than a quarter of adults over the age of 65 falling at least once a year in the US . Falls aParticipants were recruited during their visit to the Otology and Neurology clinic at Columbia University, and the study was approved by the local Institutional Review Board. Because the prevalence of hearing loss starts increasing dramatically from the age of 60 onwards , only inAudiometric measurements were conducted in a sound-treated double-walled audiometric suite using insert earphones and an audiometer calibrated to the standards set by the American National Standards Institute (ANSI S3.6-2010). Hearing sensitivity was measured through pure tone air conduction audiometry by presenting pure tone signals to the ear through earphones and varying the signal intensity until the hearing threshold was determined for each frequency. Therefore, higher thresholds indicate worse hearing. Pure tone air conduction thresholds at 500, 1000, 2000, 4000, 6000, and 8000 Hz were recorded in decibel hearing level (dB). Pure tone averages (PTA) were determined as the average hearing thresholds in dB at select tested frequencies, with higher PTA representing worse hearing at those frequencies. In this study, low frequency PTA were taken for 500, 1000, and 2000 Hz, and high frequency PTA were taken for 4000, 6000, and 8000 Hz . Low freTo collect spatiotemporal gait data in out-of-the-lab conditions, participants were asked to put on custom-engineered footwear developed in the Columbia University Robotics and Rehabilitation Laboratory . For stride length, stride height, and stride velocity, normalized metrics adjusting for the subject’s stature (as described in ) were alOther variables of interest collected include age, sex, race/ethnicity, and the DHI-S score. The DHI-S is an abbreviated 10-question version of the original 25-question DHI score, which is used the quantify perceived vestibular disability ,30. The Multivariable linear regression was employed to determine whether high and low frequency PTA of the poorer hearing ear, the left ear, and the right ear were associated with changes in gait parameters, adjusting for age, sex, race/ethnicity, and DHI-S score, which are known to affect gait patterns . Models The assumption of normal distribution of the residuals was checked by inspecting the normal probability plots of the standardized residuals. Deviations from linearity and homoscedasticity were identified by inspecting the scatterplots of the standardized residuals plotted against the standardized predicted values. We checked for potential multicollinearity among predictors using tolerance and reciprocal of the variance inflation factor, with a threshold of 0.2. The assumption of independent errors was checked using the Durbin–Watson statistic.Influential outliers were identified using the following criteria: 1) absolute value of the externally studentized residual > critical t, where df = N − p −1 with N, p being the # of data points and the # of predictors, respectively , and 2) The characteristics of the study sample are summarized in The mean and CV of all gait parameters are summarized in p < 0.01), a decrease in mean normalized stride height by 0.130 percentage points (p < 0.05), and no significant changes in other gait parameters (p = 0.01) and no changes in other gait parameters  CV by 0.814 percentage points  and 0.759 (p < 0.01) percentage points with every 10 dB increase in high frequency hearing thresholds in the right ear and the left ear, respectively; this increase was greater for increases in the right ear high frequency PTA. All standardized coefficients for the high frequency hearing thresholds were greater than the standardized coefficients for age in the same model, suggesting that the predictive ability of high frequency hearing loss for DSP CV is stronger than that of age. The DSP CV  increasep = 0.0006) percentage points with every 10 dB increase in low frequency hearing thresholds in the right ear, but not the left ear. The standardized coefficients for the low frequency hearing thresholds of the poorer hearing ear and the right ear were greater than the standardized coefficients for age in the same model, suggesting that the predictive ability of low frequency hearing loss for DSP CV is stronger than that of age. The DSP CV increased by 1.114 (Stride height was only associated with high frequency hearing thresholds in the poorer hearing ear .This study examined the relationship between spatiotemporal gait parameters and hearing thresholds in a group of older adults aged 60 to 95. The variability in DSP was found to increase with worsening high and low frequency hearing thresholds. The effect of hearing thresholds was greater than the effect of age on this gait parameter, as demonstrated by the magnitude of the standardized coefficients. The increase in DSP variability was greater for increases in hearing thresholds for the right ear compared to the left ear. Stride height was also found to decrease with increases in the high frequency hearing thresholds of the poorer hearing ear. No association was found between hearing thresholds and all other gait parameters included in the analysis.Studies investigating the relationship between age, falls, and gait parameters have identified increased variability in gait parameters as a risk factor for falls that increases with age ,35,36. FIn a previous study, perceived vestibular impairment, as determined by increased DHI-S score, was associated with changes in several gait parameters, including reduced stride length, cadence, and walking speed, and increased variability in cadence, DSP, swing period, and stance-to-swing . As the Another interesting finding in this study is that the variability of DSP increases more with hearing threshold increases in the right ear compared to the left ear. A right ear advantage for speech has been well-established, and it is thought to reflect left-hemispheric dominance . Right-eThis study has several strengths. While hearing loss increases with age, and has also been linked to falls, few studies have investigated the linkage between hearing loss and gait parameters. The use of a custom-engineered footwear-based gait analysis system enabled the collection of spatiotemporal gait parameters with high granularity, in the clinical setting, and without the space constraints associated with traditional gait laboratory equipment. The availability of rich data on hearing thresholds and spatiotemporal gait parameters enabled a thorough analysis of the relationship between spatiotemporal gait parameters and high and low frequency hearing thresholds in the right ear, left ear, and poorer hearing ear.Our study is limited by its small sample size, which may have affected the ability to detect relationships. Furthermore, it also limited the number of variables we could adjust for in our multivariable analyses; however, we adjusted for age, sex, race, and DHI-S score, which have been previously linked to changes in gait parameters. Prospective falls were not included in this analysis; therefore, definitive conclusions about the role of DSP variability as a mediator between hearing loss and falls cannot be made. Further investigation is warranted to understand these relationships. Finally, ongoing efforts are directed toward improving form factor, weight, accuracy, and usability of the footwear-based gait analysis system .In older adults, worsening high and low frequency hearing thresholds were associated with increased variability in DSP. Effects persisted after adjusting for the effects of age and perceived vestibular disability, suggesting that auditory feedback may be important for balance control and interlimb coordination beyond the effects of the peripheral vestibular system. Additionally, the increase in DSP variability was greater for increases in hearing thresholds for the right ear compared to the left ear. Future studies may investigate whether there is a right ear advantage for the influence of auditory feedback on gait.


Streptomyces argillaceus. Its biosynthesis gene cluster has been cloned and characterized, and several new analogs with improved pharmacological properties have been generated through combinatorial biosynthesis. To further study these compounds as potential new anticancer drugs requires their production yields to be improved significantly. The biosynthesis of mithramycin proceeds through the formation of the key intermediate 4-demethyl-premithramycinone. Extensive studies have characterized the biosynthesis pathway from this intermediate to mithramycin. However, the biosynthesis pathway for 4-demethyl-premithramycinone remains unclear.Mithramycin is an anti-tumor compound of the aureolic acid family produced by Streptomyces albus resulted in the production of 4-demethyl-premithramycinone, delimiting genes required for its biosynthesis. Inactivation of mtmL, encoding an ATP-dependent acyl-CoA ligase, led to the accumulation of the tricyclic intermediate 2-hydroxy-nogalonic acid, proving its essential role in the formation of the fourth ring of 4-demethyl-premithramycinone. Expression of different sets of mithramycin biosynthesis genes as cassettes in S. albus and analysis of the resulting metabolites, allowed the reconstitution of the biosynthesis pathway for 4-demethyl-premithramycinone, assigning gene functions and establishing the order of biosynthetic steps.Expression of cosmid cosAR7, containing a set of mithramycin biosynthesis genes, in We established the biosynthesis pathway for 4-demethyl-premithramycinone, and identified the minimal set of genes required for its assembly. We propose that the biosynthesis starts with the formation of a linear decaketide by the minimal polyketide synthase MtmPKS. Then, the cyclase/aromatase MtmQ catalyzes the cyclization of the first ring (C7–C12), followed by formation of the second and third rings  catalyzed by the cyclase MtmY. Formation of the fourth ring (C1–C18) requires MtmL and MtmX. Finally, further oxygenation and reduction is catalyzed by MtmOII and MtmTI/MtmTII respectively, to generate the final stable tetracyclic intermediate 4-demethyl-premithramycinone. Understanding the biosynthesis of this compound affords enhanced possibilities to generate new mithramycin analogs and improve their production titers for bioactivity investigation. Streptomyces argillaceus ATCC12956. MTM was approved as an anticancer drug in 1970 [Mithramycin (MTM) is an anti-tumor agent member of the aureolic acid family and is produced by  in 1970 –7. In ad in 1970 , and a Mmtm has been cloned and characterized [Structurally, MTM is a polyketide (PK) consisting of a tricyclic aglycone with two aliphatic side chains, which is glycosylated by a trisaccharide and a disaccharide . The MTMcterized . This hacterized . Some ofcterized –16, and cterized , 18. Thecterized , 20, whimtm BGC [Different approaches have been used to improve production of MTM and some analogs. These include overexpression of cluster specific regulators , 22, incmtm BGC . Furthermtm BGC . This apmtm BGC . All biomtm BGC , 12. Howmtm BGC contains thirty-four genes , mtmK (β-ketoacyl synthase β) and mtmS (acyl carrier protein), encoding the minimal polyketide synthase (PKS) [mtmX and mtmTI and mtmTII, which encode a putative cyclase and two ketoreductases, respectively. It also includes genes that have been shown to be dispensable for MTM biosynthesis in S. argillaceus: mtmOI and mtmOIII [mtmZ, mtmA, mtmH ; genes for deoxysugar biosynthesis  [mtmGIV) [mtmW) involved in side chain reduction [mtmL, which encodes a putative acyl-CoA ligase. Therefore cosAR7 would have the potential capability to direct the biosynthesis of 4DMPC but not any other later biosynthesis intermediate since this cosmid lacks mtmMI [Streptomyces albus to generate the recombinant strain S. albus cosAR7  , 27, these (PKS) , and these (PKS) –31. Cosmnd mtmV) , 33, and[mtmGIV) , and a keduction . In addiks mtmMI , which eid pFL3R  expressimtmL, encoding a putative acyl-CoA ligase, whose role is unclear. Comparison of the MtmL sequence with those of proteins in databases showed similarity with acyl-CoA ligases such as CmmLII, PokL and SsfL2 , encoded by the chromomycin A3, polyketomycin and tetracycline SF2575 BGCs, respectively [mtmL in the MTM pathway, this gene was initially overexpressed in the S. argillaceus wild type strain using plasmid pDZL10  IV) cloned into mtmL in the same direction of transcription to avoid a polar effect on downstream genes. The resultant mutant strain . This compound was purified and structurally characterized by NMR spectroscopy and MS  that shows a C7-C12 cyclization  expressing just the on Table  and 5b. lisation . MtmQ colisation , such aslisation  , in addition to 1  had a modified metabolite profile , with retention times of 6.3, 7 and 7.3 min, respectively. Additional expression of mtmX  were co-expressed and they showed longer retention times than compound 2, indicates they might be tetracyclic. These results confirm MtmL plays an essential role in the biosynthesis of the MTM aglycon and are consistent with its proposed role as cyclase involved in formation of the fourth ring [mtmX improved production of compounds 3 to 5. MtmX is homologous to SnoaL-family of enzymes that have been shown to mediate fourth ring closure in the biosynthesis of other aromatic polyketides [3, 4 and 5 when MtmX is co-expressed with MtmL. Previous studies on MTM biosynthesis showed that mtmOII is essential for 4DMPC production [mtmOII  production and the disappearance of compounds 3 to 5 , StfY (69%), DspY (68%) and OxyN (68%) from the kosinostatin, steffimycin, daunorubicin and oxytetracycline pathways, respectively , 50–52.  1 Figs.  and 5d. rth ring  . Then, the aromatase/cyclase MtmQ, followed by the cyclase MtmY form the first (C7–C12), second (C5–C14) and third (C3–C16) rings, generating a putative intermediate a. Spontaneous oxidation of the second ring to a quinone, a process that has also been observed for other aromatic polyketides [2). Next, MtmL adenylates the carboxyl group of compound a and collaborates with MtmX to form the fourth ring (between C1–C18), generating the putative intermediate b, and oxygenation by MtmOII, followed by reduction by MtmTI and MtmTII, affords 4DMPC (6). Oxygenation of intermediate b could involve its epoxidation followed by reductive opening of the epoxide, as previously proposed [These results demonstrate that the minimal set of enzymes required for the biosynthesis of 4DMPC is the minimal PKS MtmPKS, the aromatase MtmQ, cyclases MtmY and MtmX, the acyl-CoA ligase MtmL, the oxygenase MtmOII, and ketoreductases MtmTI and MtmTII. They also show that oxygenases MtmOI and MtmOIII are not required for the biosynthesis of 4DMPC, despite early proposals to the contrary . Based oyketides , resultsproposed .mtmL in S. argillaceus (mutant ΔL) interrupts MTM biosynthesis and results in accumulation of 2-hydroxy-nogalonic acid (2); (ii) heterologous expression of mtmPKSQY leads to the formation of 2-hydroxy-nogalonic acid (2) and in the absence of mtmL, expression of mtmX, mtmOII, mtmTI and/or mtmTII does not modify the metabolite profile, indicating that MtmL acts before the products of these genes; (iii) Co-expression of mtmL with mtmPKSQY results in the production of new compounds 3, 4 and 5, the titres of which are increased by co-expression of mtmX; and (iv) in the absence of mtmX, co-expression of mtmOII and mtmPKSQYL does not lead to the production of new compounds, suggesting that MtmX is required for biosynthesis to proceed and acts before MtmOII.In this pathway, MtmL and MtmX form the fourth ring prior to the oxidation and reduction reactions. This hypothesis is supported by the following facts: (i) inactivation of S. albus, using a sequential expression approach employing mtm gene cassettes. This has allowed the assignment of gene functions and determination of the order of biosynthetic steps. Understanding the biosynthetic pathway for 4DMPC will pave the way for improving the titre of MTM and analogs via synthetic biology approaches, and will facilitate rational creation of novel derivatives by metabolic engineering strategies. In addition, the gene cassette approach we employed here could be used in mix and match experiments with genes from other aromatic polyketide biosynthetic pathway and to reconstitute the biosynthesis of other aromatic polyketide aglycons.The pathway to 4DMPC, a key intermediate in MTM biosynthesis, has been established through in vivo reconstitution in S. argillaceus ATCC12956 a mithramycin producer, was used for gene replacement experiments. S. albus J1074 [Streptomyces protoplasts, transformation, and selection of transformants was carried out as described [Escherichia coli ET12567 (pUB307) was used as donor for intergeneric conjugation [E. coli DH10B (Invitrogen) was used as a host for subcloning. Metabolite production was carried out on R5A solid medium [us J1074  was usedescribed . Escherijugation . E. colid medium . Bioconvd medium , except Streptomyces and for E. coli [S. argillaceus DNA for 4DMPC production.Plasmid DNA preparations, restriction endonuclease digestions, and other DNA manipulations were according to standard procedures for  E. coli , 58. PCR E. coli , pUK21 [ E. coli , pEM4T [ E. coli , pEM4AT  E. coli , pEM4 [6 E. coli , and pBS E. coli , were us E. coli  was used E. coli  was usedmtm BGC were amplified and sequenced using the primers listed in Additional file Several genes from the mtmL gene replaced by the apramycin cassette in the same direction of transcription. The plasmid p∆L was used to transform S. argillaceus protoplasts. Transformants were selected with apramycin and tested for their susceptibility to thiostrepton. PCR analysis and sequencing using primers LF and Q , incubated for 7 days at 30 °C and extracted with 1:1 volume of ethyl acetate. The organic extract was evaporated under vacuum and purified by semi-preparative HPLC using an Agilent 1200 instrument fitted with a C-18 column . The following elution profile with a flow rate of 9 mL/min was applied: an isocratic condition of 5% acetonitrile for 5 min, followed by 45 min linear gradient to 100% acetonitrile. The purified samples were analyzed by high resolution UHPLC-MS on a Bruker MaXis Impact electrospray ionization time-of-flight mass spectrometer (ESI-TOF-MS) connected to a Dionex 3000 RS UHPLC instrument with UV absorption detected at 280 nm and fitted with an Agilent Zorbax Eclipse Plus C18 column  at a flow rate of 0.2 mL/min using the following elution program: 0 min, 5% ACN/95% H2O; 12 min, 100% ACN; 17 min 100% CAN (both ACN and H2O contained 0.1% formic acid). The NMR spectra were recorded at 25  °C in DMSO-d6 for SEK15 and CD3OD for 2-hydroxy nogalonic acid on a Bruker Avance II 700 MHz spectrometer. Structure elucidation of 2 was carried out using a combination of 1D and 2D NMR  and high resolution MS/MS experiments (Additional file Extraction and spectroscopic analyses of metabolites produced by escribed . For theAdditional file 1: Overexpression/deletion of mtmL. Generation of plasmid pΔL. Generation of plasmid pDZL10. Figure S1. Comparison of MtmL with putative Acyl-CoA Ligases. Figure S2. Production of MTM by strains overexpressing mtmL. Figure S3. Generation and analysis of mutant S. argillaceus ΔL.Additional file 2: Chemical characterization of SEK15. Table S1. NMR assignment.Additional file 3: Chemical characterization of 2-hydroxy nogalonic acid. Table S2. NMR assignment. Figure S4. Structure and key HMBC correlations. Figure S5. High resolution MS.Additional file 4: Generation of gene cassette plasmids for 4DMPC. Table S3. Primers used in this work.


The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.While cochlear implantation (CI) technology has greatly improved over the past 40 years, one aspect of CI that continues to pose difficulties is the variability of outcomes due to numerous factors involved in postimplantation performance. The electric acoustic stimulation (EAS) system has expanded indications for CI to include patients with residual hearing, and is currently becoming a standard therapy for these patients. Genetic disorders are known to be the most common cause of congenital/early‐onset sensorineural hearing loss, and are also involved in a considerable proportion of cases of late‐onset hearing loss. There has been a great deal of progress in the identification of deafness genes over the last two decades. Currently, more than 100 genes have been reported to be associated with non‐syndromic hearing loss. Patients possessing a variety of deafness gene mutations have achieved satisfactory auditory performance after CI/EAS, suggesting that identification of the genetic background facilitates prediction of post‐CI/EAS performance. When the intra‐cochlear etiology is associated with a specific genetic background, there is a potential for good CI performance. Thus, it is essential to determine which region of the cochlea is affected by identifying the responsible genes. This review summarizes the genetic background of the patients receiving CI/EAS, and introduces detailed clinical data and CI/EAS outcomes in representative examples. Anat Rec, 303:563–593, 2020. © 2020 The Authors.  Cochlear implantation (CI) is the surgical insertion of a device to provide electrical stimulation directly to the auditory nerve Fig. . CI is aGJB2 (29%), followed by SLC26A4 (9%), CDH23 (7%), MYO7A (4%), OTOF (5%), MYO15A (3%), and LOXHD1 (2%), indicating that these deafness genes are typical deafness genes found in the prelingual CI/EAS patients. A further 9% of the patients were diagnosed with syndromic deafness associated with other symptoms. For postlingual CI/EAS patients, a genetic etiology was detectable in ~36% of cases. Although genetic causes were the most common, a number of different kinds of causative genes, including various rare genes, were found to be involved in postlingual CI/EAS patients. The most common causative gene was CDH23 (9%), followed by MYO7A (4%), TMPRSS3 (4%), MYO15A (2%), DFNB31 (1%), ACTG1 (2%), DFNA5 (1%), MYO6 (1%), and CRYM (1%). In the postlingual CI/EAS patients, mitochondrial m.3243A>G (1%) and m.1555A>G mutations (2%) were also found to be involved. Compared to the prelingual group, many genes with autosomal dominant inheritance, such as MYO7A, ACTG1, DFNA5, MYO6, and CRYM, as well as mitochondrial genes reported to cause progressive hearing loss, were found to be involved.Although CI provides a good outcome for the majority of cases, factors affecting the outcomes of CI vary among patients. One reason of such variations is thought to be the heterogeneous cause of hearing loss. The function of the cochlea could be affected by various factors, including genetic factors, viral infections, and congenital anomalies. Among them, genetic factors represent the most common etiology in severe‐to‐profound hearing loss, and might be one of the key determinants of outcomes for CI and electric acoustic stimulation (EAS)  analysis has helped clarify genetic epidemiology; i.e., The cochlea is composed of various types of cells. The coordinated action of various molecules is essential for the normal development and maintenance of auditory processing in the cochlea. A series of studies have clarified the localization of these molecules in the cochlea  was separated, and then total RNA was extracted from each slice and converted to cDNA. Each gene has a specific expression pattern , good CI outcomes may potentially be achieved. Therefore, efforts for the identification of the region of the cochlea involved (either inside or outside the cochlea) should be made by delineating the responsible genes. Regarding the outcomes of CI, the LittlEARS auditory questionnaire was used to assess the auditory behavior development before the operation and at 3, 6, and 12 months after CI. Although scores varied among the patients, the majority of non‐syndromic hearing loss patients with specific deafness gene mutations showed good and rapid development of auditory behavior. In contrast, syndromic hearing loss patients as well as the patients with inner ear anomalies showed comparatively poorer and slower development , was the first gene identified as being involved with non‐syndromic hearing impairment , and there has been a general rule applied to the relationship between mutations and hearing loss; that inactivating mutations (deletion mutations and stop mutations) result in more severe phenotypes compared to those caused by non‐inactivating mutations (missense mutations) , and the parents were found to be carriers for the mutation  to non‐syndromic hearing loss with enlarged vestibular aqueducts , and the parents were found to be carriers for the mutation  had compound heterozygous ion Fig. . Her newion Fig. . CT scanion Fig. . COR evaion Fig.  and she ion Fig. , and a mion Fig. . CI outcSLC26A4 gene. Thereby, a clinician knew that she may experience profound hearing loss, which could potentially worsen. Amplification using hearing aids was found to be insufficient for good language development. Taken together with her etiology of hearing loss (intra‐cochlear etiology), these findings indicated that CI was the recommended intervention. Therefore, a wait‐and‐see strategy was identified as not a good option for this patient. The clinician was also able to provide information regarding the future possible appearance of other symptoms (vertigo and goiter) in association with the mutations in this gene.In this case, genetic testing identified compound heterozygous mutations in the CDH23, a member of the cadherin superfamily, encodes calcium‐dependent cell–cell adhesion glycoproteins, and is expressed in the inner and outer hair cells in the cochlea  or non‐syndromic hearing loss (DFNB12). The phenotype range of DFNB12 is variable from congenital profound hearing loss to adult‐onset high‐frequency involved hearing loss. As shown in our past studies, CDH23 mutations are often identified in patients having recessive inheritance, and one phenotypic feature is the presence of residual hearing , and the parents were determined to have been the mutation carriers  and USH1D   Fig. . He had W]) Fig. , we chosW]) Fig. . TherefoW]) Fig. . As showW]) Fig. , hearingW]) Fig. .MYO7A and MYO15A encode myosin VIIA and XVA, members of the unconventional myosin superfamily of proteins . MYO7A mutations may cause various phenotypes ranging from non‐syndromic hearing loss (DFNA11/DFNB2) to Usher syndrome (USH1B)  for the left ear at the age of 10. Residual hearing was completely preserved six months after the surgery. She uses the natural residual hearing combined with ES, and does not require any acoustic amplification at low frequency. Speech perception test results were dramatically improved   inherited from the parents  Fig. .ACTG1 encodes γ‐actin, the predominant actin isoform in the inner and outer hair cells in the cochlea. Within the hair cells, γ‐actin is an important component of the cuticular plate, adherens junctions, and stereocilia , and his father, brother, and younger son carried the same mutation. Due to progressive hearing loss and insufficient amplification by hearing aids, he received EAS at age 39. His brother showed a similar audiogram configuration from around 15 years old. Residual hearing was preserved and monosyllable tests showed dramatic improvement. Speech perception test results were dramatically improved from 20% to 80% one year after receiving the EAS  DFNB10: congenital or early childhood onset, with severe and prelingual hearing impairment, and (2) DFNB8: a later‐onset ski‐slope type audiogram and progressive postlingual hearing impairment.Tmprss3, hair cells in the organ of Corti were found to be deteriorated at the start of the basal turn, and progressing toward the apex   Fig. . PreservT]) Fig. –E. An imT]) Fig. . After bT]) Fig. .The m.1555A>G mutation in the mitochondrial 12S ribosomal RNA gene is the most common mitochondrial mutation associated with hearing loss  is predominantly expressed in the cochlear inner hair cells, and is essential for synaptic exocytosis at their ribbon synapses  is hearing loss derived from the dysfunction of auditory signals downstream of and/or including the inner hair cells. It is marked by loss of ABR signal yet retention of OAE and/or cochlear microphonics (CM). Now known as “auditory neuropathy spectrum disorder (ANSD),” AN was renamed in 2008 due to being a spectrum of associated symptoms   Fig. . Based oQ]) Fig. . Speech Q]) Fig. .LOXHD1, a known cause of DFNB77, is the gene for the protein Lipoxygenase Homology Domains 1, comprised entirely of 15 PLAT  domains   Fig. . His sisA]) Fig. . His speA]) Fig. .COCH encodes extracellular protein “cochlin” that consists of a single peptide, a late gestation lung protein Lgl1 (LCCL) domain, and two von Willebrand factor A (vWFA) domains   Fig.  Tsukada. In his ely Fig. .The above results suggest that the genes presented may be involved in hearing loss in CI patients. As patients with these mutations showed relatively good auditory performance after receiving CI or EAS, genetic background could be added as one of the factors useful in predicting performance after implantation. Also genetic testing is helpful in predicting future hearing levels; therefore, genetic diagnosis could facilitate decision making for early intervention. Furthermore, genetic testing is potentially useful for evaluating residual hearing, estimating progression, and successful hearing preservation making it valuable in the selection of candidates and electrodes for CI or EAS.The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of the data; in the writing of the manuscript, or in the decision to publish the results.


Electrical impedance spectroscopy was used as means of transduction and the obtained data was analyzed by principal component analysis (PCA). The electronic tongue was tested in deionized water, mineral water and wastewater matrices showing its ability to (1) distinguish between TCS doped and non-doped solutions and (2) sort out the TCS range of concentrations. Regarding film stability, strong polyelectrolytes, as (PEI/PSS)n, presented more firmness and no significant desorption when immersed in wastewater. Finally, the PCA data of gold IDE and (PEI/PSS)5 sensors, for the mineral water and wastewater matrices, respectively, showed the ability to distinguish both matrices. A sensitivity value of 0.19 ± 0.02 per decade to TCS concentration and a resolution of 0.13 pM were found through the PCA second principal component.Triclosan (TCS) is a bacteriostatic used in household items that promotes antimicrobial resistance and endocrine disruption effects both to humans and biota, raising health concerns. In this sense, new devices for its continuous monitoring in complex matrices are needed. In this work, sensors, based on polyelectrolyte layer-by-layer (LbL) films prepared onto gold interdigitated electrodes (IDE), were studied. An electronic tongue array, composed of (polyethyleneimine (PEI)/polysodium 4-styrenesulfonate (PSS)) Several studies had proved its allergy risk, antimicrobial resistance [−8–10−12 M concentrations range  phenol) (TCS) is widely used as an antimicrobial, antibacterial and preservative agent in different personal care and consumer products . TCS’s msistance ,7,8,9. Do-phenylenediamine on a glassy carbon electrode, using an amperometric sensor achieved a linear range of 2.0 × 10−7–3.0 × 10−6 mol/L and a detection limit of 8.0 × 10−8 mol/L [−1, and a limit of detection of 16.5 μg L−1 (57 nM) [Currently, the monitoring of TCS is a matter of concern and an important issue. Traditional analytical methods use gas or liquid chromatography and mass spectrometry ,17,18,19−8 mol/L ; a multi (57 nM) . Recent  (57 nM) ,36,37,38Accordingly, the LbL nanoassembly technique will produce nanostructures, in a flexible, easily-scalable, reproducible, and versatile approach that allows the precise control of the coating thickness, composition, and structure . This naThe aim of the present study was to explore the potential of the e-tongue concept using impedantiometric detection of TCS in environmental complex aqueous matrices. A deionized water, a Portuguese mineral water, and an effluent from a wastewater treatment plant (considered the primary source of TCS into water bodies) were used as experimental matrices. TCS was spiked to the aqueous matrices and measured using thin-films sensors based on polyethyleneimine (PEI), poly(sodium 4-styrenesulfonate) (PSS), poly (PAH), and graphene oxide GO; , which h(1) an e-tongue based in a set of five sensor devices providing the possibility to distinguish different TCS concentrations;(2) the use of electrical impedance spectroscopy measurements for TCS detection in environmental aqueous complex matrices;(3) the stability of the thin-films layers, analysis of adsorption and desorption phenomena, submitted to different aqueous matrices and pH values.− and SO42− were analyzed by ion chromatography , equipped with a conductivity detector. The experimental matrices were deionized water (DW), a Portuguese mineral water (MW), and a wastewater (EF). DW was produced using a Millipore system , MW was a commercial Portuguese mineral water and EF was the liquid fraction collected in the secondary clarifier at a wastewater treatment plant . −5–10−15 M, was made sequentially from a mother solution with a concentration of 10−4 M and analyzed immediately after preparation. All dilutions were prepared using experimental matrices/MeOH (9:1) solutions. A solution of each experimental matrix/MeOH, without TCS, was used as the blank standard (0 M).Triclosan (TCS ≥ 97%) and methanol  used were from Sigma–Aldrich . The experimental TCS dilutions range, 10−2 M diluted in water Type I, produced with a Millipore system . The adsorption time period of each layer  was 30 s and, after the adsorption of each layer, the thin-film was dried using nitrogen gas. Films of PAH/GO were prepared with 5 bilayers, (PAH/GO)5, while films of PEI/PSS were prepared with 5, 10, and 20 bilayers, designated by (PEI/PSS)5, (PEI/PSS)10, and (PEI/PSS)20, respectively. The sensor devices used in this work were purchased from DropSens  and were constituted by glass BK7 solid support with deposited gold interdigitate electrodes (IDE) comprising of 250 “fingers” each . The sup−5 M. All measurements were performed at room temperature 25 °C.The electrical analysis of aqueous matrices was performed by measuring the impedance spectra of these sensor devices when immersed in the aqueous matrices with different TCS concentrations with a Solartron 1260 Impedance Analyzer in the frequency range of 1–1000,000 Hz, applying an AC voltage of 25 mV. To avoid contamination of the sensor devices, the impedance spectra of thin-films sensors and gold IDE were recorded for the TCS experimental matrices in a sequence of increasing concentrations from 0 to 10−9 M of TCS—an average concentration found in wastewater matrices and sufficient to see changes in the UV-vis spectra. The absorbance spectra were attained using a double beam spectrophotometer UV-2101PC (Shimadzu) with a sampling interval between 800 and 200 nm, with a resolution of 0.5 nm. For each thin-film combination, three absorbance spectra were obtained: (1) before being immersed in the TCS solution (t = 0 min) to establish a baseline, (2) after five minutes of immersion (t = 5 min), and (3) after a cumulative immersion time of ten minutes (t = 10 min). Characterization of LbL thin-films stability adjusting the EF’s pH with (1:1) HNO3, for pH values of 3, 6, and 8, were also performed.The stability of thin-films on the different experimental matrices was also studied by measuring the ultraviolet-visible (UV-vis) spectra of the LbL thin-films before and after being immersed in the experimental matrices/MeOH solutions spiked with 10p < 0.05), concerning the Principal component analysis (PCA) was carried out, regarding the normalized  impedance spectroscopy data, to reduce the size of data and to obtain a new space of orthogonal components, in which different concentration patterns can be observed and explained. Additionally, an array of sensors, composed by all the thin-films and gold IDE sensors, was analyzed as an e-tongue for TCS detection in EF experimental matrix. The ANOVA was performed at 95% of confidence 5 sensor shows different behavior for MW and EF matrices, however similar to the gold IDE and (PAH/GO)5 sensor, for MW and EF matrices, respectively. Sensor physical properties (PP), such as reactance, loss tangent, and resistance at constant frequency, may present increasing or decreasing monotone functions as a function of TCS concentration. In order to allow operational TCS measurements (sensor sensitivity), a trend function of its concentration must be found, for example at a given frequency, expressed as normalized reactance, loss tangent, or resistance spectra. A normalized response can be achieve using the following relation:Different footprints were observed according to the experimental aqueous matrices and sensor devices. Similar behavior was observed for DW for all sensors. The gold IDE sensor presents a similar footprint for the MW and EF matrices. The (PAH/GO)5 and (PEI/PSS)5 sensors, at frequencies of 6.3 and 25,119 Hz, respectively, were normalized and plotted as a function of TCS concentrations in 5 sensor displays only significant sensitivity in the 10−5–10−7 M concentration range. Regarding the (PAH/GO)5 sensor 5 sensors. It should be remarked that all sensors tended to follow a decrease in the loss tangent with decreasing TCS concentrations.Concerning the TCS detection in MW solutions, the reactance spectra, represented in ent case II, the l5 sensor was shown to be the most sensitive in the studied TCS concentration range. At frequencies between 1 and 10 kHz, the reactance spectra presented a good response discrimination mination IIIc. The samples ,12, suppIn this section three questions will be addressed: 1) Are the tested sensors able to detect concentrations of TCS equal and higher than zero? 2) Are the tested sensors able of distinguish different TCS concentrations? 3) Do the tested sensors produce PCA plots with observable patterns and trends according to TCS concentrations? To look for sensor “discrimination” from different concentrations of TCS, on different matrices, the principal component analysis (PCA), a multivariate analysis technique, was performed after data normalization (Z type). The PCA was used to explore the sensors sensory attributes to produce different patterns for the range of TCS concentrations. The PCA was applied for the most sensitive sensor, regarding impedance normalized data (average of three loops impedance measurements). The PCA with the best score plots obtained for the sensors when immersed in DW, EF, and MW matrices, respectively, are presented in 5 sensor, the non-doped solution was in the same quadrant of the higher TCS concentration. A concentration pattern and trend, related to TCS concentrations, was visible for the data plot obtained by the gold IDE sensor  might be regarded as an outlier point, being the nearest concentration, in both cases 10−15 M. Additionally, for EF the effect of the number of bilayers was tested for the most sensitive sensor obtained, (PEI/PSS)5. The PCA plots, showed that five bilayers revealed better response (PCA separation to TCS concentrations) and signal intensity for impedance, when compared to the ones with 10 or 20 bi-layers of (PEI/PSS)5 5, (PEI/PSS)10, and (PEI/PSS)20 thin-films deposited, was used to test the e-tongue concept and to analyze its ability to produce discrimination among TCS concentrations in the EF matrix. The respective PCA plot, The combination of sensor arrays was expected to improve the capability of TCS concentration discrimination. The array of sensors composed by the sensor devices without any film deposited (gold IDE) and with (PAH/GO)Despite the positive response behavior of the thin-films sensors in the presence of the TCS molecules in different aqueous matrices, both individually and in an array tell us that we were on the right track for TCS detection, there is a need to evaluate the stability of the thin-films in order to confirm that the positive results are due to the presence of TCS in the aqueous matrix and not to the loss of polyelectrolyte molecules from the films by desorption. It is known that the LbL film stability is related with the electrostatic interactions, in the order of 100 kJ/mol, between the opposite ionized groups of cationic and polyelectrolyte molecules ,51. Ther−9 M TCS aqueous solutions, prepared with DW, MW, and EF . These obtained spectra were plotted together by the type of film and aqueous matrix, thus allowing for an insight on the effects of adsorption and/or desorption occurring on each LbL thin-film. Accordantly, if the absorbance is seen to increase compared to the t = 0 is likely that TCS molecules are being adsorbed on the thin-film outermost surface. Contrarily, if the absorbance is seen to decrease when compared to the spectrum measured before immersion of the film on the aqueous matrix, t = 0, it is likely that polyelectrolyte molecules are being desorbed from the thin-film. This desorption is related to losses in the electrostatic interactions with a consequence of changes in the electrical impedance measured during the sensing procedure. By analyzing the spectra of the (PAH/GO)5 thin-film displayed in Additionally, the ionic elements present in the matrices, can be adsorbed onto the polyelectrolyte’s layers, changing the electrical properties of the sensor. Thus, in order to ascertain which sensor holds the best features for the detection of TCS with no loss/desorption of thin-film layers and no irreversible adsorption of TCS onto thin-film, the adsorbed amount on the different thin-films was analyzed before and after the thin-films to be immersed on the different TCS aqueous matrices. The adsorbed amount per unit of area can be easily estimated by measuring the UV-visible spectra of the films since they absorb in this wavelength region and TCS presents two main absorbance bands at 230 and at 280 nm. In 2+, Na+, and SO42− 5 LbL films. According to [5 LbL films were highly stable. To better understand the involved phenomena, a subsequent study about the stability of (PEI/PSS)5 thin-films was conducted by measuring the absorbance spectra of (PEI/PSS)5 thin-films before and after to be immersed during different periods in EF matrices with different pH, namely, 3, 6, and 8, see Regarding the thin-films in EF, the spectra of rding to , the PEIrding to ,58, it crding to . Therefo5 thin-film was negative and, at high pH, the TCS was negatively charged, the TCS molecules were repelled by the films and were not adsorbed on its surface. Thus, neither desorption nor adsorption phenomena were observed.Clear desorption occurred after immersion in 5 LbL sensor should be applied to acid aqueous matrices with lower ionic strengths, while the (PEI/PSS)5 LbL sensor should be used with alkaline aqueous matrices with higher ionic strengths. Additionally, the gold IDE sensor should be applied to medium ionic strength in neutral solutions. Thus, to the environmental aqueous matrices under study, an array of sensors, composed by the gold IDE and (PEI/PSS)5 sensors was set in order to understand if the e-tongue concept were capable of “tasting”, through the impedance data, MW and EF, doped with TCS (The results of the previous sections indicate that the (PAH/GO)with TCS .2. In 2 were plotted as a function of TCS concentrations for both types of matrices, and a linear relation and working range of the e-tongue was attained. The principal component F2 linear tendency suggests that F2 data could be used to determine the sensitivity, the slope of a linear function, of the sensor. Analyzing F2 curves, in detail, one could infer a linear range between 10−13 and 10−7 M of the TCS concentrations. Considering the data within this concentration range, the F2 feature plot vs. the logarithm of the concentration, allows fitting the plotted data points to a straight line with a slope, s). The Cs value was 0.1 pM while the minimum value that could be measured was 0.02, therefore, −13 M and the range of detection of 10−13 to 10−7 M.The PCA plot corresponding to the use of the adequate sensor devices to the matrix is presented in −15–10−5 M, in a MW and in EF matrices, by measuring the impedance spectra of each sensor device. The thin-film stability tests related with adsorption/desorption phenomena revealed that some of the films were not appropriate as TCS monitoring tools as they were highly influenced by both matrices’ ion composition and pH. The experimental data suggests the potential of (PEI/PSS)5 LbL films combination to be employed in alkaline aqueous matrices, such as wastewater, with high ionic strength. This is contrary to the gold IDE (uncoated) sensors that reacted with ions in the solutions, were damaged by S and Zn elements, and might be considered only to analyze neutral solutions with low ionic strengths. In fact, the choice of more stable sensing layers is the key to develop quantitative e-tongues and, in the case of LbL films, that stability is only achieved when strong polyelectrolytes are employed in its preparation. An electronic tongue, consisting of an array of sensors based on uncoated IDE and coated with different LbL films was shown to be able to detect and quantify triclosan trace concentrations, within the range of 10−13–10−7 M , the e-tongue presents a sensitivity value of 0.19 ± 0.02 and a resolution of 0.13 pM. Lastly, observing the main conclusions on the thin-film stability and PCA discrimination through MW and EF, the e-tongue array studied could be used as an “analytical” sensor for the detection and quantification of TCS in the monitoring of environmental aqueous matrices. In this sense, the experimental data, analyzed through a PCA, supported and demonstrated the sensor’s ability and potential to distinguish between aqueous matrices and to discriminate TCS concentrations using the principal component F2. For an experimental/environmental range of triclosan concentrations of 10


Sickle cell anemia (SCA) is a hereditary hemoglobin (Hb) disorder associated with a very specific molecular lesion, which is the exchange of glutamic acid for valine in the sixth residue of the Hb beta chain, originating the S Hb. It is characterized by intermittent episodes of vascular occlusion and end-organ damage.Progressive organ damage may affect any organ with brain, eyes, pulmonary, hepatobiliary, spleen, genitourinary, and the musculoskeletal systems being the most commonly involved and reported. Other complications of the disease that have not been well described or studied include cranio-orbital syndromes, oropharyngeal syndromes, periodontal disease, and otologic syndromes.Considering the vaso-occlusive nature of sickle cell disease (SCD), the potential for auditory damage is not unexpected. However, the incidence of subjective hearing impairment among SCA is very low and and little is known about the relationship between SCA and hearing loss.Here we report a 43-year-old female with SCA who presented with sudden bilateral hearing loss and generalized body ache and admitted as a case of sensorineural deafness with vascular crisis; she received IV fluid and analgesia and improved after five days from the therapy. Sickle cell disease (SCD) is an inherited hematological disorder, which affects red blood cells (RBCs). Normal RBCs can squeeze through small blood vessels. However, sickled or crescent-shaped RBCs become stiff and sticky. These changes lead to difficulty in passing through small blood vessels.SCD is the most common among African, Indian, Middle Eastern, Mediterranean, and Latino descent -2.The typical presentation of SCDWhen sickle-shaped cells block small blood vessels, less oxygen reaches that part of the body, leading to widespread organ and tissue damage. Such damage causes familiar complications of SCD, which include painful episodes in the arms, legs, chest and abdomen, recurrent acute chest syndrome, a pneumonia-like symptom due to lung tissue damage, severe anemia, stroke, and painful, prolonged erections called priapism in males .Sickle cell disease sometimes associated with endocrinopathies like severe hypogonadism could be due to primary hypogonadism, recurrent testicular infarction, and zinc deficiency. Besides testicular dysfunction, sickle patients may also have abnormalities in other sex organs like prostate gland and seminal vesicles, both affected in ejaculation volume and may lead to infertility .Blood transfusion has been a traditional modality for the treatment of acute and chronic complications of SCD. It improves blood flow by decreasing the sickling of Hb polymer in addition to increased blood oxygen-carrying capacity. In some studies it is showed that blood transfusion affects the pituitary-gonadal axis and leads to significant enhancement of the sperm parameter and improved fertility .Diagnosis of SCDThere are several types of tests which are used to diagnose and monitor a sickle cell anemia (SCA) patient. Some of these tests are sickle cell test, complete blood count, hemoglobin (Hb) electrophoresis. In HbS, the complete blood count reveals Hb levels in the range of 6-8 g/dL with a high reticulocyte count [Sensorineural deafness can be due to cochlear ischemia and anoxia that happened due to vessel occlusion secondary to the sickle RBC. The cochlea is highly sensitive to ischemia because of its anatomical position which is fed by a single artery called the labyrinthine artery that can be terminal .Individuals suffering from SCD should be encouraged to have regular assessment of hearing function because of the high sensitivity of cochlea to develop reversible ischemia, especially during a vaso-occlusive crisis. Early detection of cholera ischemia and immediate intervention will prevent permanent hearing disability.A 43-year-old female with SCD since childhood has been on hydroxyurea. She had a frequent attack of a vaso-occlusive crisis with a history of avascular necrosis of both femoral heads and a history of osteomyelitis and autosplenectomy. She received multiple exchange transfusions and frequent blood transfusions complicated with iron overload and hepatic siderosis. She developed gestational cardiomyopathy with a reduced ejection fraction of 36%.She was referred to the ENT clinic because she developed bilateral hearing loss for eight days more on the left side not associated with tinnitus, dizziness, or ear discharge. This condition was not preceded by an upper respiratory infection. Her condition was associated with generalized body pain and she was admitted to the hospital for sickle cell crisis and received IV hydration.On examination there was no pre- or postauricular tenderness; her bilateral tympanic membranes were intact and there was no congestion or fullness. Weber's test showed Weber to the right ear. The hearing test was done: pure tone audiogram showed: see Figure Moderate to severe left sensorineural hearing loss (AB at 500 Hz + 4 kHz).Right mild sensory neural hearing loss (AB at 250 Hz + 8 kHz).Tympanogram showed: Type A bilaterally, Hb 5.9. She received IV fluids and analgesia and her condition drastically improved.Sickle cell disease is the most common among black people. Hypoxia and dehydration are major precipitating factors for the sickling of RBCs. The structural changes that happened due to the sickling of RBCs reduce the capacity of RBCs to transport oxygen through the entire body .Sudden onset sensorineural deafness is a rare complication of SCD. It could be unilateral or bilateral, mild or severe. The underlying mechanism of deafness is due to vascular occlusion because of the obliteration of the end terminal artery (Labyrnthine artery) that leads to cochlear damage. The tendency of cochlear to develop ischemia is very high, so specialized care and attention must be achieved to prevent hearing disability .Multiple studies showed that underlying pathophysiology of cochlear impairment due to deformity of RBCs which blocks the blood supply to the high metabolic area consumes a high amount of oxygen to maintain the electrical balance of the endolymph. However, a lack of oxygen to the organ of Corti would cause extensive and severe cochlear damage that will explain the lack of otoacoustic emission in patients with SCD .Meticulous literature review failed to explain the pathophysiology of inner ear complications in patients with SCD. However, the impairment blood supply of cochlea may be the root cause of these abnormalities. All hypotheses agreed that changes in cochlear blood supply in individuals with SCA initiate progressive local hypoxia that leads to cellular damage and permanent deafness . There was a cross-sectional study done in 2018 which investigated the prevalence of sensorineural hearing loss in children and adolescents with SCA which showed that 28.8% of SCD exhibited sensorineural deafness .Another study done in 2005 investigated 183 sickle cell subjects with a different variety of Hb electrophoresis , each subject received a routine audiological and electrophysiological assessment. It showed 80% of the hearing impaired sickle cell subjects had Hb SS. The remaining hearing impaired sickle cell subjects were Hb SC 7% and Hb S beta-thalassemia 7% .It seems from previous studies that there is a directly proportional relationship between the concentration of Hb S and the tendency to develop sensorineural deafness. So the major preventive measuring is by decreasing Hb S either by drug therapy like hydroxyurea or by exchange transfusion. In summary, the otologic complications of SCD in general and deafness, in particular, are not well understood and poorly studied.It is an obvious need to link SCD and sensorineural deafness and early diagnosis of hearing loss. Underdiagnosis or late diagnosis of hearing loss may lead to irreversible damage to the linguistic, biopsychosocial, and emotional development of patients who suffer from SCD.