Acoustic Reflex Testing Research Articles

Effects of long-term azithromycin therapy on auditory functions in children with chronic respiratory diseases

Background and objectivesIn recent years, long-term azithromycin (AZT) use has been increased in pediatric patients with chronic respiratory tract problems. In this study, we aimed to assess auditory functions in children on long-term AZT therapy. MethodThe study included 43 patients who received long-term AZT treatment and 27 age-matched, healthy controls. In the study and control groups, ear-nose-throat examination, pure tone audiometry, speech recognition threshold (SRT), speech discrimination score (SDS), uncomfortable loudness level (UCL), acoustic reflex tests, and otoacoustic emission tests were performed. The test results were statistically compared between groups. ResultsMean age was 11.3 ± 0.56 years in the study group and 9.3 ± 3.07 years in the control group. The medain hearing examination was 8 months after end of AZT treatment (Ranged: 1–12 months). No significant difference was found in normal- and high-frequency audiogram tests at any frequency between study and control groups. Also, no significant difference was found in distortion product otoacoustic emissions (DPOAE) and transient evoked otoacoustic emissions (TEOAE) tests between groups. Also, there was no significant difference in acoustic reflex, SRT, SDS, and UCL test results between study and control groups. ConclusionThis is the first study assessing auditory functions comprehensively in pediatric patients who received long-term AZT therapy. In this study, it was shown that long-term AZT use had no deleterious effect on auditory function tests.

Prevalence of and factors affecting otitis media with effusion in children in the region from Balkans to Caspian basin; A multicentric cross-sectional study

ObjectiveThe aim of our study was to contribute to the literature about the prevalence of OME by conducting a research in a wide geography examining most of the associating factors together with a questionnaire. Additionally, possible effects of altitudes and latitudes, concordance between the otoscopic examination findings and tympanometric and acoustic reflex test results were evaluated in 4-7 years old children in the same season in different countries. MethodsIn the randomly sampled schools from different regions of different cities where people of different scoioecomonic statuses live, 4-7 year-old children were included in the study. The results of the questionnaire covering the potential factors in OME etiology were evaluated together with the results of the otoscopic examination and tympanometry findings, and also the acoustic reflex findings to direct the interpretation in cases of low amplitude - blunted peak tympanograms which can be interpreted as a "Type B" or “Type As”. All the results were gathered in the same season. ResultsTen centers from nine countries participated in the study. A total of 4768 children were evaluated. The frequency of OME diagnosed by otosopic examination was 22.48% (n=1072) and the diagnosis rate when otoscopic examination plus type B tympanometry were taken into account was found as 11.3% (n=539) in general population. Factors increasing the prevalence of OME were found as; mother's educational level (p=0.02), child’s age (p=0.006), history of upper respiratory tract infection (p=0.001), smoking father (p=0.01), mother being a housewife or laborer (p=0.01), history of allergy (p=0.001), asthma (p=0.04), or allergy symptoms (p=0.02). No direct relationship was found between altitudes or latitudes and prevalence of OME. ConclusionThe important affecting factors found after analyzing all of the potential risk factors in the same model are secondhand smoke exposure, low level of mother’s education, mother’s occupation, positive history of URTI, and age of the child being less than 7. By paying attention to the factors that increase the prevalence of OME, putting particular emphasis on the preventable ones such as smoking, education, and fighting with allergies could decrease the prevalence of this public health issue.

Neurodegenerative Diseases and the Auditory-Vestibular System

Neurodegenerative Diseases and the Auditory-Vestibular System

Effects of adipokinetic hormone/red pigment-concentrating hormone family of peptides in olfactory bulbectomy model and posttraumatic stress disorder model of rats

One of the major neuropeptide groups in insects is adipokinetic hormone/red pigment-concentrating hormone (AKH/RPCH) family of peptides. AKH had improving effects on depression and anxiety in animal models and it may be a new treatment choice in these disorders. Aim of this study was to investigate effects of Anax imperator AKH (Ani-AKH), Libellula auripennis AKH (Lia-AKH) and Phormia-Terra hypertrehalosemic hormone (Pht-HrTH) on animal behavior in olfactory bulbectomy (OBX) model and in posttraumatic stress disorder (PTSD) model of Wistar-albino rats. Lia-AKH and Pht-HrTH significantly increased time spent in escape platform’s quadrant compared to sham control while Lia-AKH significantly increased time spent in escape platform’s quadrant compared to OBX controls in probe trial of Morris water maze (MWM). Ani-AKH, Lia-AKH and Pht-HrTH significantly decreased immobility time compared to OBX controls in forced swimming test (FST). Pht-HrTH significantly increased %open arm time compared to OBX controls in elevated plus maze (EPM) test. Ani-AKH significantly increased %open arm entry compared to sham control while Ani-AKH and Pht-HrTH significantly increased %open arm entry compared to OBX controls in EPM. In PTSD study Ani-AKH and Lia-AKH significantly decreased immobility time compared to traumatized controls in FST. In acoustic startle reflex test, Ani-AKH, Lia-AKH and Pht-HrTH significantly decreased average startle amplitude compared to non-traumatized controls in PTSD study. Metabolomic studies showed that AKH may affect glutamatergic and dopaminergic system and neurochemistry. In conclusion, AKH peptides had wide ranging effects on behavior and improved performance in OBX and PTSD models in rats.

Acoustic Reflexes in Individuals Having Hyperacusis of the Auditory Origin.

Functional role of the acoustic reflex in preventing over stimulation of the inner auditory system by decreasing sound intensity along with the previous reports of acoustic reflex abnormalities in individuals having hyperacusis point towards the involvement of acoustic reflex deficit in the origin of hyperacusis especially when any medical condition leading to hyperacusis is not associated. However this issue remains contradictory owing to limited comprehensive investigation. This study was undertaken to ascertain the relationship between hyperacusis and the acoustic reflex. Threshold, amplitude and latency of the acoustic reflex were measured in two different groups of individuals having hyperacusis; Group 1: 14 individuals having hyperacusis with hearing loss (HwHL) and Group 2: 17 individuals having hyperacusis without hearing loss (HwoHL). Control group (Group 3) consisted of 15 normal hearing individuals who never experienced hyperacusis. Result showed a significant group effect on all the measured characteristics of the acoustic reflex. ARTs were found to be significantly higher in HwHL and HwoHL when compared to NHwoH. ARTs were statistically similar for HwoHL and NHwoH. HwoHL's ARAs and ARLs were significantly smaller and prolonged, respectively, when compared to HwHL and NHwoH. HwHL and NHwoH had statistically similar ARAs and ARLs. This study confirms acoustic reflex abnormalities in some individuals having hyperacusis with or without hearing loss. It further highlight the importance of involving acoustic reflex testing in the assessment of hyperacusis especially when hyperacusis is not associated with hearing loss or any other medical condition that may lead to hyperacusis.

A novel method: can stapedial acoustic reflex have a role in the diagnosis of minimal hepatic encephalopathy?

Stapedial acoustic reflex is an easily accessible and applicable test which is also valuable for the clinical conditions which affect the various locations of the central nervous system. Searching the diagnostic value of stapedial acoustic reflex at minimal hepatic encephalopathy is the aim of this research. Diagnosis of minimal hepatic encephalopathy was conducted by mini-mental state and critical flickered frequency tests. Minimal hepatic encephalopathy diagnosed patients were established in the first group. Cirrhosis (without minimal hepatic encephalopathy or overt hepatic encephalopathy) diagnosed patients were created the control group. The stapedial acoustic reflex test was applied for minimal hepatic encephalopathy and the control group by audiologists in a soundproof room. In total, 221 patients were screened and 97 patients meet the inclusion criterions. Out of 97 patients, 52 were the minimal hepatic encephalopathy patients and the remaining patients were the control group. Acoustic reflex tests battery includes the evaluation of two pathways called ipsilateral and contralateral. Ipsilateral way test results were found positive in all minimal hepatic encephalopathy patients and 95% positive in the control group. Contralateral acoustic reflex test results were found 36% positive in minimal hepatic encephalopathy patients and 95% positive in the control group, respectively. A comparison of ipsilateral and contralateral acoustic reflex test results was displayed a statistical significance. Stapedial acoustic reflex test results of cirrhosis patients may cover additional parameters for the diagnosis of minimal hepatic encephalopathy.

Effect of mild and chronic neonatal hypothyroidism on sensory information processing in a rodent model: A behavioral and electrophysiological study

Thyroid hormones are essential for neonatal brain development. It is well established that absence of thyroid hormones during critical periods of development can alter sensory functions such as visual and auditory processing, but there are few studies on rat somatosensory system development at mild, long-term, and irreversible neonatal hypothyroidism. Thus, the current study was conducted to investigate whether chronic thyroid hormone insufficiency would alter different cognitive aspects of tactile information processing and sensory motor filtering at behavioral or neuronal levels. Neonatal Wistar male rats were exposed to 0 and 6 ppm of propylthiouracil for 150 days. Behavioral tests including tactile discrimination tests and acoustic startle reflex test were performed. Using extracellular single unit recording technique, barrel cortex neurons’ excitatory and inhibitory responses to controlled displacement of whiskers were evaluated. Results indicated that percentage of correct choice in tactile learning and discrimination of a new texture decreased in hypothyroid group compared to the control group (P < 0.05). In addition, acoustic startle reflex of hypothyroid group significantly decreased compared to the control rats when the prepulse intensity was 71 dB (P < 0.05). Data obtained from electrophysiological tests showed that spontaneous activity and response magnitude of barrel cortex neurons decreased in hypothyroid group compared to the control group (P < 0.05). It is concluded that, thyroid hormones can regulate tactile and auditory sensory processing in male rats, and mild and long-term absence of these hormones can result in deficiency in natural functions of these sensory systems.

Comparison of Otoacoustic Emissions in Asymptomatic Diabetes Mellitus and Normal Hearing Control Groups

Background: Diabetes mellitus (DM) is a chronic metabolic disorder. Previous studies reported the hearing impairment of diabetes patients as a progressive bilateral symmetrical sensorineural hearing loss (SNHL) of gradual onset which predominantly affected the higher frequencies, and found that diabetic patients had unsatisfactory hearing thresholds than nondiabetics in the same age group. For the use of evoked otoacoustic emissions (EOAEs) as a clinical test of hearing, EOAEs are sound which can be recorded in the outer ear canal and give objective information about preneural, mechanical elements of the cochlear function.&#x0D; Objective: To compare the otoacoustic emissions of asymptomatic DM patients with a normal hearing control group.&#x0D; Methods: All subjects received a routine audiologic evaluation which consisted of pure-tone air-bone conduction tests, tympanograms, and stapedius acoustic reflex tests. OAEs were measured in 30 asymptomatic diabetic patients with a mean age of 55.73 years and an age-matched 30 subjects normal hearing control group with a mean age of 50.87 years.&#x0D; Results: The pure-tone thresholds at 3, 4, 6, and 8 kHz; transient-evoked otoacoustic emissions (TEOAEs) amplitudes at 1, 1.5, 2, and 3 kHz; and the distortion product otoacoustic emissions (DPOAEs) amplitudes at 1, 1.5, 2, 3, 4, and 6 kHz were significantly different (P &lt; .05) between the asymptomatic and control groups.&#x0D; Conclusions: This study suggested that diabetic patients had a significant hearing impairment. SNHL is gradually progressive and is a common condition in DM patients and their thresholds for hearing are higher at higher frequencies.

Evaluation of hearing results in Behçet's disease

Objectives: Behçet's disease is an inflammatory rheumatic disease with recurrent scarring in the oral and genital area, as well as skin, eye, joint, vein, and nerve involvement. The aim of the study was to investigate the level of hearing in Behçet’s disease and whether there is a change in hearing levels as the level of the disease increases. Methods: In this study we examined 32 patients with Behçet’s disease and 50 healthy volunteers. All patients were evaluated with audiometry, tympanometry and acoustic reflex tests, as well as detailed ear, nose, and throat examinations. Results: Sensorineural hearing loss was observed in 9.3% of the patients with Behçet's disease, according to the audiological data, and all patients were bilateral. We also observed sensorineural hearing loss to be the fifth most common symptom in our study. Especially in high frequencies, there was positive correlation between hearing levels and disease exposure time (p &amp;lt; 0.05). Conclusions: We think that the audiological examinations should be included in the routine check-ups of Behçet's patients. In addition, a follow-up assessment of the hearing level of these patients with high frequency audiometry may be more meaningful.

Acoustic Reflex Latency (ARL) Assessment in Malaysian Adults: The Effects of Age, Gender and Stimulus Frequency

In the field of auditory neuroscience, acoustic reflex is a useful clinical test for hearing diagnosis and site of lesion assessment. Nevertheless, the latency measurement of acoustic reflex has not been widely studied and more research efforts are warranted. The present study aimed to determine the influences age, gender and stimulus frequency on acoustic reflex latency (ARL) among healthy adults. Seventy-two Malaysian adults (35 males and 37 females) participated in this prospective comparative study. They were categorized into three age groups: young adults (n = 30, mean age of 26.6 ± 4.3 years), middle-aged adults (n = 21, mean age of 45.8 ± 5.7 years) and older adults (n = 21, mean age of 58.2 ± 1.2 years). They underwent the standard ipsilateral acoustic reflex testing and ARL results were analyzed at 500, 1000, 2000 and 4000 Hz. The mean ARL values obtained are in line with the previous reports. While no significant influences of gender and stimulus frequency were found on ARL results, the mean ARL values were statistically higher in the older adults than in the other age groups. To conclude, a notable effect of age was found on the latency of acoustic reflex. In contrast, the ARL results do not appear to be influenced by either gender or stimulus frequency. The age-specific normative data for ARL gathered from the present study (n = 144) are useful for clinical and future research applications, particularly among Malaysian population.

Investigation of high-frequency hearing loss and outer hair cell function of the cochlea in patients with psoriasis: a case-control study.

The inner ear can be the target of autoimmune attacks, and sensorineural hearing loss can occur as a complication in various non-organ-specific autoimmune diseases. The aim of this study was to compare cochlear functions and hearing evaluation in patients with psoriasis and controls. In total, 29 patients with psoriasis and 30 healthy controls (HCs) were included in the study. Pure-tone audiometry at 250, 500, 1000, 2000, 4000, 8000, 10 000, 12 000, 14 000 and 16 000 Hz was performed for patients as HCs, as were immittance measures including tympanometry, acoustic reflex and otoacoustic emission testing. There were statistically significant (P < 0.05) differences between patients and HCs for pure-tone thresholds at high frequencies, and for distortion product otoacoustic emission (DPOAE) responses and signal : noise ratio at all frequencies. In our study, based on DPOAE and audiological findings, there was damage to the outer hair cells of the cochlea, resulting in high-frequency hearing loss in patients with psoriasis.

Predictive Accuracy of Sweep Frequency Impedance Technology in Identifying Conductive Conditions in Newborns.

Diagnosing conductive conditions in newborns is challenging for both audiologists and otolaryngologists. Although high-frequency tympanometry (HFT), acoustic stapedial reflex tests, and wideband absorbance measures are useful diagnostic tools, there is performance measure variability in their detection of middle ear conditions. Additional diagnostic sensitivity and specificity measures gained through new technology such as sweep frequency impedance (SFI) measures may assist in the diagnosis of middle ear dysfunction in newborns. The purpose of this study was to determine the test performance of SFI to predict the status of the outer and middle ear in newborns against commonly used reference standards. Automated auditory brainstem response (AABR), HFT (1000 Hz), transient evoked otoacoustic emission (TEOAE), distortion product otoacoustic emission (DPOAE), and SFI tests were administered to the study sample. A total of 188 neonates (98 males and 90 females) with a mean gestational age of 39.4 weeks were included in the sample. Mean age at the time of testing was 44.4 hr. Diagnostic accuracy of SFI was assessed in terms of its ability to identify conductive conditions in neonates when compared with nine different reference standards (including four single tests [AABR, HFT, TEOAE, and DPOAE] and five test batteries [HFT + DPOAE, HFT + TEOAE, DPOAE + TEOAE, DPOAE + AABR, and TEOAE + AABR]), using receiver operating characteristic (ROC) analysis and traditional test performance measures such as sensitivity and specificity. The test performance of SFI against the test battery reference standard of HFT + DPOAE and single reference standard of HFT was high with an area under the ROC curve (AROC) of 0.87 and 0.82, respectively. Although the HFT + DPOAE test battery reference standard performed better than the HFT reference standard in predicting middle ear conductive conditions in neonates, the difference in AROC was not significant. Further analysis revealed that the highest sensitivity and specificity for SFI (86% and 88%, respectively) was obtained when compared with the reference standard of HFT + DPOAE. Among the four single reference standards, SFI had the highest sensitivity and specificity (76% and 88%, respectively) when compared against the HFT reference standard. The high test performance of SFI against the HFT and HFT + DPOAE reference standards indicates that the SFI measure has appropriate diagnostic accuracy in detection of conductive conditions in newborns. Hence, the SFI test could be used as adjunct tool to identify conductive conditions in universal newborn hearing screening programs, and can also be used in diagnostic follow-up assessments.

Findings of Acoustic Stapedial Reflex Test in Newborns with and without Risk Factor

Objectives: The aim of this study was to determine the rates of acoustic stapedial reflexes (ASR) presence and to assess the test­­-retest reliability of ASR at a 1000 Hz probe tone in newborns with and without risk factor. Materials and Methods: Screening Transient Evoked Otoacoustic Emission (TEOAE), Automated Auditory Brainstem Response (AABR), tympanometry and ASR tests were performed on 59 ears with risk factor (research group) and 44 ears without risk factor (control group) within 0 ‒ 2 weeks following birth. Afterwards, tympanometry and ASRs were repeated one month later. Results: In terms of ASR thresholds, there is no significant difference between the two groups (p>0.05). Detection rates of ipsilateral ASRs were higher than those of contralateral ASRs in the first assessment for both group. Conclusion: Ipsilateral ASRs in neonates can be obtained in the early postnatal period, but contralateral ASRs can be detected late, especially one month after birth. ASR is an essential diagnostic test battery in newborns because it gives clinicians more information about the entire hearing system.

Is middle ear pressure affected by continuous positive airway pressure use?

Is middle ear pressure affected by continuous positive airway pressure use?

Pressurized Wideband Acoustic Stapedial Reflex Thresholds: Normal Development and Relationships to Auditory Function in Infants.

This study analyzed effects of pressurization on wideband acoustic stapedial-muscle reflex (ASR) tests in infants cared for in normal newborn (NN) and neonatal intensive care units (NICU). Effects of hearing-screening outcomes on ASR threshold measurements were also evaluated, and a subsequent longitudinal study established normative threshold ranges over the first year after birth. An initial experiment compared thresholds in newborns measured at ambient pressure in the ear canal and at the tympanometric peak pressure. ASR thresholds for broadband noise were higher for ears that did not pass newborn hearing screening and ASR threshold was 14dB higher for real-ear compared to coupler conditions. Effects of pressurization were significant for ears that passed screening; thus, ASR testing in infants should be conducted at tympanometric peak pressure. ASR threshold was significantly higher for ears that referred on transient evoked otoacoustic emissions and Auditory Brainstem Response (ABR) screening tests and also for ears with conductive and sensorineural hearing loss diagnosed by ABR. Developmental ASR changes were significant over the first year for both normal and NICU infants. Wideband pressurized ASR thresholds are a clinically relevant measure of newborn hearing screening and diagnostic outcomes.

Acoustic reflex patterns in amyotrophic lateral sclerosis.

The aim of the study is to investigate acoustic reflex testing in amyotrophic lateral sclerosis patients. Amplitude, latency, and rise time of stapedial reflex were recorded for 500 and 1000 Hz contralateral stimulus. Statistical analysis was performed by the Wilcoxon test and the level of significance was set at 5%. Fifty-one amyotrophic lateral sclerosis patients and ten sex- and age-matched control subjects were studied. Patients were further divided in two groups: amyotrophic lateral sclerosis-bulbar (38 cases, with bulbar signs at evaluation) and amyotrophic lateral sclerosis-spinal (13 cases, without bulbar signs at evaluation). Stapedial reflex was present in all patients. There was a statistically significant difference in the mean amplitude, latency, and rise time between the amyotrophic lateral sclerosis patients as compared with the controls. Amplitude was lower in both the amyotrophic lateral sclerosis-bulbar and the amyotrophic lateral sclerosis-spinal patients than in the controls (p<0.05) and rise time was longer in both patient groups compared with the controls (p<0.05). These results confirm the presence of abnormal acoustic reflex patterns in amyotrophic lateral sclerosis cases with bulbar signs and, moreover, suggesting a possible subclinical involvement of the stapedial motor neuron even in amyotrophic lateral sclerosis-spinal patients. Amplitude and rise time seem to be good sensitive parameters for investigating subclinical bulbar involvement.

Evaluation of the acoustic (stapedius) reflex test in children and adolescents with peripheral facial nerve palsy

IntroductionThe stapedius nerve is one of the branches of the facial nerve in the temporal bone. It supplies the stapedius muscle, which is responsible for the attenuation reflex that protects the inner ear from loud noises. The stapedius (acoustic) reflex (SR) test is useful in identifying the site of facial nerve injury. The return of the SR (acoustic) to normal after an injury is a good prognostic factor in the treatment of facial nerve palsy. ObjectiveThe aim of this study was to evaluate the effect of FNP on the SR (acoustic) response and determine the acoustic reflex threshold (ART) levels on the affected side. Material and methodIn this study, 70 patients, 3–7 years old, were screened. The study population consisted of 26 boys (37%) and 44 girls (63%). Follow-up tests were performed 3–18 months after the initial tests. ResultsMost patients in the study population had a negative SR (acoustic) response on the affected side. In other patients, mean ART values were statistically higher on the affected side. There was no statistically significant relationship between a reflex response and the time from the onset of facial nerve palsy. DiscussionIn the available literature, the SR (acoustic) testing is limited in determining whether or not the reflex is present without stimulus frequency or ART measurements. It is estimated that the reflex response is negative with ipsilateral stimulation on the affected side in 35–80% patients. ConclusionsThe SR (acoustic) is absent in most patients on the affected side. The ART value was statistically higher on the affected side. The SR (acoustic) response was statistically time independent.

Prevention and management of hearing loss in syndromic craniosynostosis: A case series

ObjectiveTo assess the audiological profile in a cohort of children affected by syndromic craniosynostosis. MethodsEleven children with Apert syndrome (n=4), Saethre-Chotzen syndrome (n=3), Muenke syndrome (n=2), Crouzon syndrome (n=1) and Pfeiffer syndrome type 1 (n=1) were submitted to a complete audiologic evaluation including otoscopy, pure-tone audiometry, tympanometry and acoustic reflex testing, ABR, otoacustic emissions, temporal bone High Resolution CT (HRCT) scan. The main outcome measures were prevalence, type and severity of hearing loss, prevalence of chronic otitis media, correlation with the time of first surgical correction. ResultsSeven of 11 patients (64%) presented hearing loss (HL), conductive in 3/7 patients (43%) and mixed in 4/7 (57%). No patients showed a purely sensorineural HL. All hearing impaired patients displayed middle ear disorders: the patients with conductive HL had otitis media with effusion (OME) and 3/4 patients with mixed HL showed tympanic alterations or cholesteatoma. A bilateral vestibular aqueduct enlargement was detected by HRCT scan in one normal hearing patient. The ABRs resulted normal in all cases. ConclusionOur study confirms the high prevalence of otologic diseases in such patients. In contrast with previous studies, middle ear disorders were responsible for the hearing impairment also in patients with mixed HL due to secondary inner ear damage. These findings restate the necessity of a close audiologic follow-up. We did not detect the specific ABR abnormalities previously reported, possibly because of an early correction of the cranial vault malformations.

Evaluation of Acoustic Reflex and Reflex Decay Tests in Geriatric Group.

To determine average acoustic reflex thresholds in geriatric groups by assessing ipsilateral and contralateral acoustic reflex and reflex decay tests. A total of 25 elders between ages 65-84 years (74.3±5.4) and 25 individuals between ages 18-45 years (30.4±4.2) were recruited for the study. After ear, nose, and throat examination, ipsilateral and contralateral acoustic reflex thresholds at 500, 1000, 2000, and 4000 Hertz (Hz) were determined and a reflex decay test at contralateral 500 Hz was conducted. Ipsilateral acoustic reflex thresholds were obtained with high-frequency band, low-frequency band, and wide band noise, and the results were compared with ipsilateral acoustic reflexes at 500, 1000, 2000, and 4000 Hz. There was no statistically significant difference between the two groups in ipsilateral and contralateral acoustic reflex measurements at 500, 1000, 2000, and 4000 Hz (p>0.05). Negative reflex decay was obtained in all participants and no statistically significant difference between the two groups was observed in terms of reflex decay thresholds (p>0.05). Acoustic reflex with high-frequency band noise was observed in five of nine elders whose acoustic reflexes were not obtained at 2000 and 4000 Hz, whereas acoustic reflex with low-frequency band noise was observed in one of six elders who did not show reflexes at 500 and 1000 Hz. It was concluded that although some changes were observed due to age, middle ear and stapes muscles work normally in geriatric group. In the reflex decay test, reliable results were obtained at contralateral 500 Hz. Acoustic reflex measurements with low- and high-frequency band noise may also be used to assess middle ear functions.

Auditory Neuropathy/Dyssynchrony in Biotinidase Deficiency.

Biotinidase deficiency is a disorder inherited autosomal recessively showing evidence of hearing loss and optic atrophy in addition to seizures, hypotonia, and ataxia. In the present study, a 2-year-old boy with Biotinidase deficiency is presented in which clinical symptoms have been reported with auditory neuropathy/auditory dyssynchrony (AN/AD). In this case, transient-evoked otoacoustic emissions showed bilaterally normal responses representing normal function of outer hair cells. In contrast, acoustic reflex test showed absent reflexes bilaterally, and visual reinforcement audiometry and auditory brainstem responses indicated severe to profound hearing loss in both ears. These results suggest AN/AD in patients with Biotinidase deficiency.