Cyclosporine causes no hearing defect in paediatric patients with nephrotic syndrome.

OBJECTIVE: We aimed to evaluate the ototoxicity of cyclosporine A (CsA) in children with nephrotic syndrome (NS). DESIGN: Data of paediatric patients with NS followed in paediatric nephrology department were evaluated retrospectively, and hearing functions were evaluated by pure tone audiometry (PTA) and transient evoked otoacoustic emissions (TEOAEs). Age, gender, type of NS, duration and cumulative doses of immunosuppressives were noted. STUDY SAMPLE: The patients who had received CsA (n: 16) and immunosuppressives other than CsA (n: 13) for at least 6 months formed two patient groups and healthy cases formed a control group (n: 20). Children with known previous hearing defect, inner ear trauma or surgery, recurrent otitis media and those using hearing aid were excluded. RESULTS: Gender, age at first clinical presentation, laboratory tests and number of relapses were similar between the groups. No hearing loss was defined in PTA at frequencies of 250, 500, 1000, 2000, 4000 and 8000 Hz. The results of TEOAEs were similar between the groups and compatible with normal hearing. CONCLUSIONS: CsA is not responsible for permanent sensorineural hearing loss in children with NS, and there is no sufficient evidence to consider routine hearing assessment in children with NS treated with CsA.

Evaluation of the effect of acetyl L-carnitine on experimental cisplatin ototoxicity and neurotoxicity.

INTRODUCTION: Cisplatin (CDDP) is an effective and widely used chemotherapeutic agent for pediatric tumors, and ototoxicity is one of the dose-limiting side effects. OBJECTIVE: It was the aim of our study to investigate the effect of acetyl L-carnitine (ALCAR) on experimental CDDP ototoxicity by audiologic tests, histomorphologic, immunohistochemical and ultrastructural examinations and to investigate the apoptotic pathways. MATERIALS AND METHODS: Wistar albino rats (n = 28) were studied. Baseline audiological tests were performed in 4 groups: group 1, control; group 2, ALCAR; group 3, CDDP; group 4, CDDP + ALCAR-administered rats. Control audiological tests were performed on the 3rd day, and then the rats were sacrificed. Ear and brain specimens were examined by transmission electron microscopy, and caspase 3, 8 and 9 activities were investigated. RESULTS: The CDDP-administered rats showed significant auditory brainstem response threshold shifts using all stimuli (clicks, 6-kHz and 8-kHz tone burst) compared with the control groups. The CDDP + ALCAR-administered rats showed significant auditory brainstem response threshold shifts by only click stimuli compared with the control groups. In the brain, spiral ganglion and organ of Corti, ultrastructural damage was prominent in group 3; the number of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling)-positive cells and caspase 3, 8 and 9 immunostaining cells was significantly high in group 3. CONCLUSION: ALCAR improves CDDP-induced auditory impairment, and also antioxidative and antiapoptotic properties of ALCAR on CDDP ototoxicity were supported by the findings.

The effect of melatonin on experimentally-induced myringosclerosis in rats.

OBJECTIVES: This study determined the preventive effect of melatonin on the occurrence of experimentally-induced myringosclerosis of the tympanic membrane (TM). MATERIALS AND METHODS: Twenty Wistar albino-type rats weighing approximately 300 g each were randomly separated into two groups and myringotomized on the left TMs: group 1 rats (n=6) received intraperitoneal melatonin injections 10 mg/kg/day whereas group 2 rats (n=12) were treated with physiological serum only. The remaining two rats were served as the control group for histological comparison and standardization. After 15 days of treatment, myringotomized membranes were examined by otomicroscopy and harvested for histopathological evaluation. The functional effect of myringosclerotic plaques in the TMs of the two groups were compared with tympanometric measurements. RESULTS: Tympanic membranes in group 2 revealed extensive myringosclerotic plaques, on the other hand, TMs in group 1 showed faint or no existence of myringosclerosis. The mean magnitude of the maximum admittance from group 2 measured by tympanometry reduced to about 40% of the values obtained from group 1 (Z=-2,067, p=0.041). The mean magnitude of the maximum admittance from melatonin group was very close to the mean tympanometric value of non-myringotomized Wistar albino rats, demonstrating a functional outcome. CONCLUSION: The occurrence of myringosclerosis following experimental myringotomy can be hindered by systemic melatonin treatment.

Evaluation of the effect of acetyl L-carnitine on experimental cisplatin nephrotoxicity.

BACKGROUND/AIMS: To evaluate the protective effects of acetyl L-carnitine (ALCAR) on cisplatin-induced nephrotoxicity in rats, and to gain insights into the possible protective mechanisms of ALCAR against nephrotoxicity. METHODS: Twenty-eight Wistar rats were divided into four groups. Group 1 was administered saline only, group 2 was administered ALCAR, group 3 was administered cisplatin, and group 4 was administered ALCAR prior to cisplatin. Rats were sacrificed after 72 h of cisplatin/saline infusion. Serum creatinine and glomerular filtration rate values were obtained, and kidney samples were examined by light and electron microscopy. Apoptotic cell death and caspase-3, 8 and 9 activities were studied immunohistochemically. RESULTS: In group 4, ALCAR administration resulted in an improvement in kidney function tests. Histopathological findings confirmed the biochemical data. Whilst the fusion of the foot processes of podocytes was observed in group 3, they were intact in group 4 on electron-microscopic examination. Apoptotic cell death and caspase-3, 8 and 9 activities were also decreased in group 4 compared to group 3. CONCLUSIONS: Antioxidative, antiapoptotic and anti-inflammatory properties of ALCAR were supported by the findings that this agent improves kidney function tests and has the effects of tissue protection and inhibition of apoptosis in cisplatin-induced nephrotoxicity.

Examination and Comparison of Electrically Evoked Compound Action Potentials and Electrically Evoked Auditory Brainstem Response Results of Children with Cochlear Implantation without Inner Ear Anomaly.

OBJECTIVE: To investigate the relationship between electrically evoked compound action potentials (ECAP) and electrically evoked auditory brainstem responses (EABR) in children with cochlear implants (CI) without inner ear anomalies. METHODS: Sixteen children between the ages of two and six years who were CI users participated in the study. ECAP thresholds were recorded from one electrode in the basal, medial, and apical regions of the cochlear implant. EABRs were recorded from electrodes whose ECAP thresholds were determined. The latency-intensity functions, amplitude and morphological analyzes of the eIII and eV waves at 200 and 180 current unit (CU) excitation levels were performed. The data obtained were analyzed statistically. RESULTS: ECAP thresholds were found to be 171.5±11.38, 169.69±20.32 and 160.81±20.03 CU at the basal, medial and apical electrodes, respectively. EABR thresholds were also found to be 169.69±12.17, 165.62±16.41 and 160±15.49 CU in basal, medial and apical electrodes, respectively. There was a strong positive correlation between ECAP and EABR thresholds in apical, medial and basal electrodes (p<0.05). EABR threshold levels were not significantly different between basal, medial and apical region electrodes (p>0.05), and ECAP threshold values were significantly different between apical and basal region electrodes (p=0.002). When the significance values of EABR eV wave latencies were analyzed in terms of electrode region, the difference between basal and apical regions was found to be significant (p=0.03). CONCLUSION: Consistency was found between ECAP and EABR recordings. However, it was concluded that one could not be preferred over the other because the data quality of the two tests was different. In future studies, ECAP and EABR recordings may be recommended by selecting more electrodes for stimulation.

The frequency of auditory neuropathy detected by universal newborn hearing screening program.

OBJECTIVE: Auditory neuropathy/auditory dyssynchrony (AN/AD) has become a well-accepted clinical entity. The combined use of oto-acoustic emissions (OAEs) and auditory brainstem response (ABR) testing in the universal newborn hearing screening (UNHS) has led to the easy recognition of this disorder. Although, we are now able to diagnose AN/AD reliably, little is known about its epidemiology, etiology, and especially the frequency of its occurrence. The primary goal of this study was to determine the frequency of AN/AD in the Western Anatolian region of Turkey. The secondary goal was to compare the detection rate of AN/AD before and after the implementation of the UNHS in the audiology department of Dokuz Eylul University Hospital. METHOD: Between 2005 and 2007, among the 23,786 newborns who were screened by automated click evoked oto-acoustic emissions (a-CEOAE) and automated auditory brainstem responses (a-ABRs), 2236 were referred to our department. All necessary audiological tests were performed for all the referred newborns. Among them, babies with deficient or abnormal ABR in combination with normal OAEs were considered as having AN/AD. These babies were evaluated with additional diagnostic audiological tests. Furthermore, comparison of the incidence of children diagnosed with AN/AD before and after the implementation of UNHS in our audiology department was also performed. RESULTS: Among the referred newborns, 65 had abnormal or deficient ABR test results. Ten of these 65 newborn babies (mean diagnostic age: 5.7 months) with hearing impairment showed electrophysiological test results that were consistent with AN/AD. The frequency of AN/AD in these 65 children with hearing loss was 15.38%. Moreover, the frequency of AN/AD within UNHS was found to be 0.044%. Seven of the 10 babies with AN/AD had hyperbilirubinemia as a risk factor, which is a high rate to be emphasized. On the other hand, the retrospective investigation of children diagnosed with AN/AD in the same audiology department between 1999 and 2005 (i.e. before the implementation of UNHS) revealed only 7 children, with an average diagnostic age of 34 months. CONCLUSION: After implementing the UNHS, the incidence of AN/AD in the audiology department increased from 1.16 to 4.13. Furthermore, the age of diagnosis of AN/AD decreased from 34 months to 5.7 months. This study shows that AN/AD, when screened, is a comparatively common disorder in the population of hearing-impaired infants. While newborn hearing screening provides early detection of babies with hearing loss, it also helps to differentiate AN/AD cases when the screening is performed with both a-ABR and automated oto-acoustic emission (a-OAE) tests. Thus, the routine combined use of a-ABR and a-OAE tests in UNHS programs, especially for the high-risk infants, can provide better detection of newborns with AN/AD. Furthermore, hyperbilirubinemia is merely an association and maybe etiologically linked.

No association between hearing loss due to bilateral otitis media with effusion and Denver-II test results in preschool children.

OBJECTIVE: Otitis media with effusion (OME) is the most common cause of acquired hearing loss in childhood and has been associated with delayed language development and behavioral problems. In this study, children with an evidently recurrent otitis media were investigated. The present study examines the association between hearing loss versus developmental screening test parameters of preschool children. METHODS: Sixteen children with bilateral otitis media were compared with age-matched same number of children with normal hearing (controls). RESULTS: Language and verbal cognitive abilities were not affected significantly as a result of the presence of hearing loss because of OME. Using internationally standardized Denver-II test to evaluate the language development and other developmental screening parameters, no significant difference was found between the patient and control groups. CONCLUSIONS: This study failed to find any association between the hearing loss due to otitis media with effusion and speech and language parameters in preschool children.

The protective effect of intratympanic dexamethasone on cisplatin-induced ototoxicity in guinea pigs.

OBJECTIVE: The purpose of this study was to investigate the effectiveness of intratympanic dexamethasone injection as a protection agent against cisplatin-induced ototoxicity. STUDY DESIGN AND SETTING: The four groups of guinea pigs were injected as follows: 1) cisplatin, 2) intratympanic dexamethasone, 3) cisplatin following intratympanic dexamethasone, and 4) cisplatin after intratympanic saline. Before and 3 days following injections, the ototoxic effect was measured with distortion product otoacoustic emissions (DPOAEs). RESULTS: The DPOAEs amplitudes and signal-to-noise ratio (SNR) values at 1 to 6 kHz frequencies for group 1 animals after injections significantly decreased over those before injections (P < 0.05). In group 2, there were no significant differences in DPOAE amplitude and SNR values between before and after intratympanic dexamethasone injections (P > 0.05). Considering group 3, there were also no significant differences in DPOAEs amplitudes and SNR values before and after of dexamethasone and cisplatin injections (P > 0.05). CONCLUSIONS: Intratympanic dexamethasone injection did not cause any ototoxic effect; in contrast, it might have a significant protective effect after cisplatin injection.

Tympanometric changes in an experimental myringosclerosis model after myringotomy.

HYPOTHESIS: The goal of this experimental study was to investigate the specific effect of myringosclerosis on tympanograms in the tympanic membranes of myringotomized rats by using otomicroscopy, tympanometry, and histopathology. BACKGROUND: Myringosclerosis is a common sequela of ventilation tube treatment of otitis media with effusion. The condition involves the hyalinization and calcification of the collagen layer in certain areas of the tympanic membrane. Previous animal experiments suggest an intimate relationship between the formation of myringosclerosis and an increased oxygen concentration in the environment of the wound after myringotomy. The result of a myringotomy therefore is an increased production of free oxygen radicals, initiating irreversible tissue damage involving fibrosis, hyalin degeneration, and finally apoptosis as observed in myringosclerosis. We propose an experimental model specific for creating sclerotic plaques solely on the tympanic membrane and for performing tympanometric measurements on this pure myringosclerosis model without creating any abnormality in the middle ear to test in what proportion myringosclerosis contributes to decrease of amplitude in tympanograms. METHODS: To assess the normal tympanometric values of Wistar albino rats, the pressure and peak admittance of the left middle ears were measured using a semiquantitative computerized clinical admittance meter using a sound frequency of 226 Hz. Twelve animals were randomly selected for the myringotomy group and perforations in the left ears were created. All tympanic membrane perforations in this group had healed and closed prior to the otomicroscopic examination and no pathologic reaction was observed in the external ear canals of rats. Otomicroscopic and tympanometric measurements were carried out on Day 15 and the degree of myringosclerosis was noted before the animals were killed. Twelve specimens in the myringotomy group were histopathologically examined for the presence of myringosclerotic plaques. RESULTS: Under light microscopy, extensive sclerotic lesions were found in the tympanic membranes of the myringotomy group, and these sclerotic deposits were located in the lamina propria. The myringosclerosis occurred predominantly adjacent to the handle of the malleus, but also near the annular region. In all ears with myringosclerosis, the magnitude of the maximum admittance reduced to approximately 50% of the Day-0 values, and this reduction was statistically significant (Z=-3.061, p=0.002). CONCLUSION: The present findings in this study are consistent with the fact that the movement of the tympanic membrane is hampered by lesions of sclerotic material, resulting in a decrease of amplitude in tympanograms (such as Type As) without any effusion or inflammation in the middle ear.

Protective Effect of Korean Red Ginseng on Cisplatin Ototoxicity: Is It Effective Enough?

OBJECTIVE: The aim of our study was to investigate the effects Korean Red Ginseng (KRG) on cisplatin (CDDP) ototoxicity in vivo and in vitro. MATERIALS AND METHODS: The first part of the study was conducted on the House Ear Institute-Organ of Corti 1 (HEI-OC1) cell line. Cells were treated with CDDP, KRG, and their combination for 24 h. Cell viability, apoptosis, and the expression of 84 apoptosis-related genes were analyzed. In the second part of the study, 30 Wistar albino rats were divided into five groups. Baseline distortion product otoacoustic emissions (DPOAEs) and auditory brainstem response (ABR) measurements were obtained. In groups I, II, and III, only saline, KRG, and CDDP, respectively, were given. In group IV, 500 mg/kg KRG and in group V, 150 mg/kg of KRG were administered for 10 days. In groups III, IV, and V, 16 mg/kg CDDP injections were administered on day 11. On day 14, final DPOAEs and ABR measurements were completed. The rats were then sacrificed, and their inner ear structures were evaluated by transmission electron microscopy. RESULTS: In the first part of the study, pretreatment with 1 mg/mL KRG protected cells from CDDP ototoxicity. This protection was mainly due to a decline in apoptotic gene expression and an increase in antiapoptotic gene expression. In the in vivo part of the study, we found that both KRG doses had otoprotective effects. This protection was more prominent at the lower dose, especially on the spiral ganglion and the brainstem. CONCLUSION: KRG was shown to be an otoprotective agent against CDDP-induced ototoxicity both in vivo and in vitro.

Friend or foe? Effect of oral resveratrol on cisplatin ototoxicity.

OBJECTIVES/HYPOTHESIS: Our objectives were to study effects of orally administered resveratrol (RV) against cisplatin (CDDP) ototoxicity in different doses and to investigate ultrastructural changes in the cochlea and brainstem. STUDY DESIGN: In vivo study using an animal model. METHODS: Thirty-two male Wistar albino rats were divided into six groups. Baseline distortion product otoacoustic emissions (DPOAEs) and auditory brainstem response (ABR) measurements were made. In groups I, II, and III, only saline, RV, and CDDP were given, respectively. Group IV, V, and VI animals were administered 10 mg/kg/day, 1 mg/kg/day, and 0.1 mg/kg/day of RV for 10 days, respectively, before 16 mg/kg CDDP injections were administered on day 11. All animals were sacrificed after repeated DPOAEs and ABR measurements were made on day 14. Cochleas of animals were investigated with transmission electron microscopy. Apoptosis were investigated with caspase-3 activity and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method in the brainstem. RESULTS: In groups IV and V, DPOAEs and ABR findings revealed that oral administration of RV 10 mg/kg/day and 1 mg/kg/day doses before CDDP injection enhanced ototoxicity. In group VI, electomicroscopy revealed better ultrastructural findings than in the cisplatin group; however, these changes were not reflected in the audiological findings accordingly. CONCLUSIONS: Our results implied that there were noticeable differences between different oral RV doses used for cisplatin ototoxicity. Especially in higher doses, RV was observed to enhance cisplatin ototoxicity.

Discussion of the dizziness handicap inventory.

PURPOSE: A review of the Dizziness Handicap Inventory (DHI). NUMBER OF STUDIES: Seventy-four studies. MATERIALS/METHODS: Articles published between January 1990 and May 2012 were identified by searches in PubMed electronic database. Of the 227 articles meeting the inclusion criteria 74 were reviewed. These articles are discussed under nine topics; Reliability, validity and internal consistency of the original version of DHI, relationship between vestibular/balance tests and DHI, association between DHI and the other scales related to balance impairments, exploratory factor analysis of the DHI, screening version of DHI, translations of DHI into other languages, the role of DHI to assess the success of the treatment of balance disorder, DHI results in various vestibular disorders, general characteristics of DHI in patients with balance impairment. CONCLUSIONS: Self reported measures represent unique pieces of the information important for the management of dizzy patients. DHI is the most widely used self reported measurement of patients with dizziness. It has been translated into fourteen languages, so it is widely accepted.

Montelukast is as effective as penicillin in treatment of acute otitis media: an experimental rat study.

BACKGROUND: Leukotrienes are the major factors in the formation of edema and mucus, as well as development of tuba Eustachii dysfunction in acute otitis media. We developed an experimental acute suppurative otitis media model and compared the responses of rats to penicillin and combinations of leukotriene antagonist with respect to histopathological observations conducted in early and late phases. MATERIAL AND METHODS: A total of 83 ears from 56 Wistar rats were used in this study. Pneumococcus suspension was injected trans-tympanically into all rats. Subjects were classified into 4 different groups with 14 rats in each. In Group A, intramuscular penicillin G was injected for a period of 5 days. In Group B, intraperitoneal montelukast was injected for 21 days in addition to penicillin. In Group C, intraperitoneal montelukast isotonic NaCl in Group D was injected into rats for 21 days. RESULTS: No significant difference was found between the groups, except for mucosal vascularization with respect to mucosal and TM parameters in early phases. Furthermore, considerable deviations were observed for the recuperation of TM and mucosal inflammation for groups in which subjects were injected with montelukast as compared to other groups of the study in the late phases. CONCLUSIONS: When the parameters of inflammation in the rat middle ear were compared with each other, most of these parameters did not show any statistically significant beneficial effects in montelukast and penicillin groups.

Otoprotective effect of recombinant erythropoietin in a model of newborn hypoxic-ischemic encephalopathy.

OBJECTIVE: The aim of this study is to test the hypotheses that central auditory pathology as well as inner ear pathology is contributing mechanisms to observed hypoxic-ischemic encephalopathy (HIE) induced hearing loss and that recombinant erythropoietin (rhEPO) will reduce this cellular pathology and attenuate hearing loss. METHODS: Twenty-eight 7-day Wistar albino rat pups were divided into four groups: Control group (n=8) was given only intraperitoneal saline solution. Sham group (n=5) had only a midline neck incisions without carotid ligation under general anesthesia and administration of intraperitoneal saline solution. HIE group (n=8) and rhEPO treated group (n=7) were subjected to left common carotid artery ligation followed by 2.5h hypoxia exposure to a mixture of 8% oxygen and 92% pure nitrogen. HIE group was injected with intraperitoneal saline solution, while the rhEPO treated group received rhEPO 100 U/kg within the same volume as the saline-alone solution. At the end of the seventh week of age hearing (ABRs) was evaluated in response to clicks, 6 kHz and 8 kHz tone burst stimuli. Animals were sacrificed and both temporal lobes, cochleas and brainstems of the animals were collected. Tissue samples were evaluated with light microscopy, immunohistochemical studies, including TUNEL and caspase-3 stainings, and electron microscopy. RESULTS: Hearing thresholds were elevated in HIE animals. In rhEPO treated animals, ABR values were similar to controls. HIE caused apoptotic changes in brainstem structures as shown by light microscopy and immunohistochemical methods. Apoptotic changes also were found within the organ of Corti, spiral ganglion cells and neurons of temporal lobe by electron microscopic investigation. In rhEPO animals many of these apoptotic changes were observed, but reduced compared to untreated animals. CONCLUSIONS: Mechanisms underlying HIE-induced hearing loss are based on apoptosis in inner ear; however central auditory pathway pathology occurs as well, likely contributing to changes in auditory processing and perception of complex signals not reflected by the ABR threshold shifts. For both clinical and basic significance 'rhRPO' is found to reduce those effects.

Features of unilateral hearing loss detected by newborn hearing screening programme in different regions of Turkey.

OBJECTIVE: Newborn hearing screening (NHS) works well for babies with bilateral hearing loss. However, for those with unilateral loss, it has yet to be established some standard rules like age of diagnose, risk factors, hearing loss degree. The aim of this study is to identify the demographic characteristics of newborns with unilateral hearing loss to obtain evidence based data in order to see what to be done for children with unilateral hearing loss (UHL). METHOD: Newborn hearing screening data of 123 babies with unilateral hearing loss, 71 (57.7%) male and 52 (42.3%) female, were investigated retrospectively. Data provided from the archives of six referral tertiary audiology centers from four regions in Turkey. Data, including type of hearing loss; age of diagnosis; prenatal, natal and postnatal risk factors; familial HL and parental consanguinity was analyzed in all regions and each of the Regions 1-4 separately. RESULT: The difference between data obtained in terms of gender and type of hearing loss was detected as statistically significant (p<0.05). While UHL was significantly higher in females at Region 1, and in males at other Regions of 2-4; SNHL was the most detected type of UHL in all regions with the rate of 82.9-100.0%. There were not significant differences between regions in terms of the degree of hearing loss, presence of risk factors, family history of hearing loss, age at diagnosis and parental consanguinity (p>0.05). Diagnosis procedure was completed mostly at 3-6 months in Region 4; whereas, in other regions (Regions 1-3), completion of procedure was delayed until 6 months-1 year. CONCLUSION: This study indicates that the effect of postnatal risk factors, i.e. curable hyperbilirubinemia, congenital infection and intensive care is relatively high on unilateral hearing loss, precautions should be taken regarding their prevention, as well as physicians and other health personnel should be trained in terms of these risks. For early and timely diagnosis, families will be informed about hearing loss and NHS programme; will be supported, including financial support of diagnosis process. By dissemination of the NHS programme to the total of country by high participation rate, risk factors can be determined better and measures can be increased. Additionally, further studies are needed with more comprehensive standard broad data for more evidence based consensus.

Cochlear implantation in neurobrucellosis.

OBJECTIVE: To report the first successful cochlear implantation (CI) in neurobrucellosis. PATIENT: A patient with bilateral total sensorineural hearing loss and other neurologic sequela due to neurobrucellosis from a country in which the disease is epidemic was successfully rehabilitated with CI. INTERVENTIONS: Clinical, laboratory, radiodiagnostics, and audiological. MAIN OUTCOME MEASURES: Sensorineural hearing loss due to neurobrucellosis may be the result of an injury anywhere along the auditory pathway, and candidacy for CI should be thoroughly evaluated and promontory stimulation test seems to be most helpful in this regard. RESULTS: Cochlear implantation may be successful in patients with sensorineural hearing loss due to neurobrucellosis. CONCLUSION: Positive promontory stimulation test is useful for selecting patients for CI deafened by neurobrucellosis.

The effect of stimulus duration on perception of Turkish vowels in normal-hearing and hearing-impaired children.

The objective of the study was to examine the effects of stimulus duration on vowel perception in normal-hearing and hearing-impaired children. For this purpose, 80 semisynthetic vowel stimuli consisting of eight different Turkish vowels with ten different durations were presented to 14 normal-hearing and 15 hearing impaired children, and they were asked to identify the vowel they heard. Thirteen normal-hearing adults served as speaker subjects to get normative data on mean durations of the Turkish vowels. While there was no significant effect of duration on perception in normal-hearing children, perception errors for very short and very long vowels were observed in hearing-impaired children. The most frequent responses as a function of duration showed four different patterns: (1) three vowels were perceived correctly in all durations; (2) two were perceived correctly in middle and longer durations; (3) two were perceived correctly in middle duration; and (4) only one was perceived correctly in short duration. It was concluded that the effects of stimulus duration on vowel perception were determined by natural duration of the vowel in a given language, and unnaturally short and long vowels were misperceived by hearing impaired subjects.