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Objectives :Determining the frequency distribution of hearing disorders among the student of public elementary school by Otoscopy, Puretone Audiometry, impedance Audiometry and questionnaires.
Methods and Materials: This study was can-led out in a cross - sectional descriptive survey - on 1000 students (500 girls and 500 boys) among the student of primary school of EslamAhad Gharh, academic year 1376-77
Results: 1- Otoscopy examination abnormal conditions of external ear canal was found in 13.65% of cases mostly impacted ceruman (13.3%). Abnormal conditions of external ear canal was more prevalent in girls than boys and the difference was statistically meaningful in the right (P V=0 .012) and left (PV=0.043) ear. Abnormal tympanic membrane was seen in 6.75% of cases mostly retraction (295%).
2- Impedance Audiometry: 11.05% abnormal tympanograms were observed, mostly type C (4.1%).
3- Pure Tone Audiometry: An overall 9.7% hearing loss was found in this population including 3.5% bilateral and
6.2% unilateral hearing loss. 4.15% of population suffered from SNHL observed mostly in boys and conductive. Hearing loss mostly in girls and the difference was statistically meaning in the left ear (PV=0.03).25.8% of cases were in need of medical care and surgery and six of them (l.e 0.6%) were in need of rehabilitation services.Family background showed on effects on the hearing disorders.Only 11. 4% of parents, 13.4% of teachers and 14.4% of afflicted students were aware of the problem.

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Objectives: determining the frequency distribution of hearing disorders among the student of public elementary school by Otoscopy, Puretone Audiometry, Impedance Audiometiy and questionnaires.
Methods and Materials:This study was carried out in a cross - sectional descriptive survey - on 1200 students (600 girls and 600 boys) among the student of primary school of Neishabbor, academic year 1376-77
Results:1- Otoscopy examination abnormal conditions of external ear canal was found in 14.1% of cases mostly impacted ceruman (13.6%) Abnormal conditions of tympanic membrane (0.4%) and foreign body 0.16%. Abnormal conditions of external ear canal was statistically unmeaningful. (P V=0 .8)
2- Impedance Audiometiy: 5. 75% Abnormal tympanograms were observed, mostly type C (3.15%)
3- Pure Tone Audiometry: An overall 5.5% hearing loss was found in this population including 3% bilateral and 1.25% unilateral hearing loss. Only conductive hearing loss was found in this population (2.7% in right ear and 3.5% in left ear), PV=0.9.Hearing loss observed mostly in girls but the difference was slight.Family background showed no effects on the hearing disorders.9.8% of cases were in need of medical care and 0.3% were in need of rehabilitation services.Only 28.8% of parents, 36.3% of teachers and 40.9% of afflicted students were aware of the problem.

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Materials and Methods: This study was performed in two parts: included development and standardization of the test and the second part was the evaluation stage. In the first section, Watson&aposs crieria fpr valid speech recognition tests for children was considered. In order to balance the lists phonemically, it was necessary to determine Persian phonemes&apos frequency -of- occurences. Thus, the frequency -of- occurences for 29 phonemes of Persian language in children&aposs and adults&apos speech were separately determined. There were significant differences between some phonemes&apos frequencies in the two samples. So&apos their frequencies in children&aposs speech was used to design the test. It should be mentioned that each list could contains only 25 vowels, while almost 32 ones were meeded according to the phonemically balancing procedure. Therefore, vowels and consonants were separately balanced. The required monosyllabic words were extracted from the books written for 4 to 6 years old children. Finally, four closed set (3- picture matrix) 25 word lists were prepared. The lists were recorded on magnetic cassette in one of the IRIB studios.To assess the test validity and reliabity, 33 normal hearing children were randomly selected from kindergartens over the city of Tehranand were tested at the Audiology Clinic of the Rehabilitation Faculty, Tehran University of Medical Sciences in 1998. The tests included: otoscopy, pure tone & immittance audiometry, establishing speech reception threshold, and speech recognition test - retest by these lists.
Findings: 1- Normal hearing children obtained 92-100 percent scores for each list at their most comfortable loudness levels through test - retest.
2- No significant difference was observed in test - retest scores in each list (p>0.05).
3-No significant difference obtained between the lists test or retest scores (p>0.O5).
4-No significant difference was observed between children&aposs scores in terms of their age and gender (p>O.OS)
Conclusion: this study, therefore, is reliable and valid. The lists are phonemically balanced and equal in difficulty. Due to the conditions under which the test was designed (including, phonemic balance, necessity of using the words that could be pictured and of the presence of tow other word in children&aposs vocabulary which is similar in auditory aspects), only the content validity for word familiarity decreased a little that could be overcome by introducing them through pictures prior to the start of the test.

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Method and Materials: This cross - sectional survey is carried out in pediatric clinic department of audiology faculty of rehabilitation, TMSU, on spring 1998. 102 top grade ranking children with normal hearing threshold

Results:1- The thresholds were not significantly different at any frequency (P>0.05) in test re-test trials.
2- The test minus re-test threshold for individual ears showed clinically reliable and acceptable range 0-10dB SPL for at least
99.74% of the ears at all frequencies.
3- The threshold differences between right & left cars in two test sessions were not significantly different (P>0.05) except for 14KHz.
4- High- frequency threshold in two test sessions showed no significant difference between girls & boys at all frequencies (P>0.05) (except for 16 & 20 KHz in right ear and 10 KHz in left ear).
Conclusion: This test can be used for evaluation of individual high-frequency threshold in all frequency as test re-tests tria1. Moreover, this test may use as a beneficial tool for monitoring different endogenous and exogenous auditory pathologies.
Consideration: it is found that this research is valid only among situation of this project. Any generalization needs further research.

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Objective: Infants hearing screening as one of the best methods of identification and hence early intervention to prevent side effects and appropriate rehabilitation if necessary.
Methods and Materials: 175 0-7 day infants were tested in two groups (112 normal history and 63 high risked) with a dumb (for low frequencies)and receiver (for high Frequencies) at 90-95 dB SPL in three hospitals. The acceptable responses were auropalpebral reflex (APR) , startle and stop of movements.
Results: Of the first group 51% showed APR, 10% startle, 22 % Both and 17% no response. Of the second group 47% showed APR, 24% startle, 11% both reflexes and 18% no response.
Conclusion: 14 cases (8 girls and 6 boys) out of 175 infnats showed no response.

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Arachnoid cysts are cerebrospinal fluid-filled sacs that are located between the brain or spinal cord and the arachnoid membrane, one of the three membranes that cover the brain and spinal cord. They are usually located within subarachnoid space with a membrane consisting of arachnoid cells and collagen fibers and are filled with CSF. It is naturally considered as a congenital cyst because of its common appearance in the infancy. Typical symptoms of an arachnoid cyst around the brain include headache, nausea and vomiting, seizures, hearing and visual disturbances, vertigo, and difficulties with balance and walking. MRI and CT can help in diagnosis. Arachnoid cysts are benign and the vast majority remains asymptomatic throughout life. If they are deemed to be causing symptoms then surgery can be contemplated. Here, we are aimed at describing a case of Arachnoid cysts involved cerebellopontine angle that has been reffered to audiology clinic in Tehran University of Medical Sciences. The experiments and results of radiographic techniques has been brought here.

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Method & Material: This study was performed on 36 normal-hearing subjects aged 18-25 years for survey of temporary threshold shift (TTS) by transient evoked otoacoustic emissions. Finding: Noise can affect the pure-tone thresholds and (TEOAEs) amplitudes. When cochlea affected by noise, evaluating TEOAE is more suitable than pure-tone audiometry. Because of this test, is objective an unaffected by attention and alertness and can be evaluated in difficult to test subject and also have high carefulness and can be performed in a quiet, but not sound-proof room.

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Objective: Determining the frequency of hearing disorders and hearing aid using in the clients referring to the Avesina education and health center, audiometry clinic, 1377.
Method and Material: This is an assesive-descriptive survey that conducted on more than 2053 (1234 males and 819 females) who referred for audiometry after examination by a physician. Case history, otoscopy, PTA, speech and immittance audiometry were conducted for all the clients. The findings were expressed in tables and diagrams of frequency. The age and sex relationship. All types of hearing losses and the number of the hearing-impaired clients need a hearing aid were assessed.Findings: 56% of this population were hearing-impaired and 44% had normal hearing were hearing. 60% were males and 40% females. Of the hearing-impaired, 44% had SNHL, 35.6% CHL and 8.2% mixed hearing loss. The hearing aid was prescribed for 204 (83 females and121 males) if they need that only 20 females and 32 males wear it.
Conclusion: It this sample, SNHL is of higher frequency. According to this survey, the more the age, the more the hearing aid is accepted (85% of wearer are more than 49) the prevalence of the hearing impaired males are more than females (60% versus 40%). Only 25% of the hearing-impaired wear hearing aids.

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Objective: The purpose of study was identify hearing loss in thalassemic patients with history of Desferrioxamine (DFO) therapy. This study was carried out in a cross-sectional descriptive survey on 195 thalassemic patients (3-30 years old) in Gazvin Thalassemia center and Tehran pediatrics&apos medical center.
Methods: The patients underwent routine otolaryngologic history and physical examination, along with standard pure-tone audiometry.
Results: Hearing loss was present in 43.1% of patients. 16% of patients had conductive hearing loss and 4.6% of patient had sensory neural hearing loss. 22.5% of thalassemic patients had high-frequency sensory neural hearing loss and more importantly, high-frequency hearing loss attributable to Desferrioxamine ototoxicity was present in 12% of patients. Furthermore, these evaluations showed that there is a significant relationship between hearing loss and DFO usage and hearing loss too. There is no significant relationship between hearing loss and ferritin level between hearing loss and age of DFO usage too.
Conclusion: Management of these patients requires proper dosing of Desferrioxamine, along with regular otolaryngolgic and audiometric follow-up in order to prevent the effect of ototoxicity of desferal.

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Method & Material: This descriptive analytical survey was performed in pars Hospital, Tehran on 45 children (22 girls, 23 boys aged 2-5 years, 1377-78 (solar).Finding: In 2-3 years old group, accurdacy of PTA test (87/7%) was more than FNS test (66%). In 3-5 years old group, Specificity & NPV showed no significant differences, between two test.
Conclusion: Since the PTA showes greater possibility of false positive response than FNST, the accuracy of the latter test is greater the PTA.

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Objective:Determining the prevalence of hearing loss and correlated factors in clients referring to audiology clinic of Buali hospital.
Method and Material: This cross-sectional analytic-descriptive survery was carried out on six thousand and twenty ears of 3010 clients (1651 ,ae amd 1359 female) in Audiology clinic of Buali hospital , during Sept 2000 to Sept 2001.
Results: Hearing loss is the most common reason for referring the clients (20.5%). 1319 ears (21.9%) Showed sensorineural hearing impairment and conductive and mixed hearing loss are observed in 1059 (17.6%) and 234 (3.9%) ears, respectedly. Hearing loss degree most cases is mild (14%) in both ears. There is no significant difference between male and female hearing threshold means (p>0.05) ‘ but a significant difference between hearing thresholds is observed in terms of age (p<0.05). Audiogram configuration in most cases is flat (55.1%). Otoscopic examination reveals abnormal condition in 2333 ears (38.8%) . 37.2% of the studied cases have abnormal tympanogram mostly type B (15.9%). 2.2% of the clients wear hearing aid that mostly have B.T.E ones (1.5%). 6.2% of the clients , depends on their hearing impairment type and degree need rehabilitation services.
Conclusion: The results are Valid only in the context of this study and it&aposs generaliztion needs further researches.

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Objective : To assess neonates and children suffering from meningitis , during the critical and recovery periods , using ABR , EOAE and Behavioral Audiometry.
Method and Material: 40 neonates to 12-year-old children were assessed. Using ABR test, the hearing of these cases was evaluated during the critical period-that is , 24-72 hours following the diagnosis. This test was repeated when patients recovered from meningitis-that is 24 hours before discharge (recovery period) Hearing function , again , was assessed 7-14 days following discharge through Immittance Audiometry, Behavioral Audiometry (PTA , SF and BOA). And EOAE (TEOAE and DPOAE) tests procedures.Findings: During the critical period , ABR test revealed normal hearing in 35 patients (87.5%) and severe to profound sensorineural hearing loss (unilateral and bilateral) in 5 patients (12.5%-girl=4, boy=1). The same result were obtained in re-evaluation in the recovery period. On the other hand , 7-14 days after of discharge , Immittance Audiometry and Behavioral Audiometry (including PTA , S.F and BOA tests), confirmed the mentioned results (cross - gcheck). EOAE test (DPOAE and TEOAE) in 35 normal hearing patients (according to ABR test) , showed normal cochlear function. 2 out of 5 cases suffering from severe to profound sensorineural hearing loss revealed normal cochlear function. According to EOAE results , abnormal cochlear function was evident in 3 patients.
Conclusion: ABR , EOAE tests , and Behavioral Audiometry in children meningitis during the critical period and recovery period can be used to diagnose any degree of hearing loss with a high level accuracy. The results of persent study is confirmed by previous investigations.

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Background and Aim: Hearing sensitivity is so vital for musicians as loud music can cause hearing loss. The aim of this study was to assess hearing sensitivity of musicians in order to determine the effects of music exposure on hearing organ.
Materials and Methods: This case-control study  was conducted on 15 string musicians with musicianship history of more than 10 years and 15 normal hearing subjects. They all were male and 20-30 years old. TEOAEs and DPOAEs performed after otoscopy , immittance and pure tone audiometry in octave frequencies between 250 to 16000 Hz.
Results: There is not significant difference between pure tone thresholds of two groups for all frequencies.A significant difference of TEOAE is found between two groups for total response and amplituds of TEOAEs . DPOAEs amplituds are not significantly different between two groups .
Conclusion: Musicianship may  affect TEOAEs amplitudes , but cannot affect results of PTA and DPOAEs. Therefore this can be useful to detect cochlear lesions secondary to music exposure and also as a tool in hearing protection program.

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Background and Aim: High frequency audiometry (HFA) provides a valuable tool and optimal index for distinguishing and monitoring many pathologies of the ear. The purpose of this study was to measure the reliability of HFA threshold in children.
Materials and Methods : In this cross-sectional study , 100 normal-hearing children, of 7 to 13 years old, including 50 boys and 50 girls were examined with a Belton 2000 audiometer and Sennheiser HD 250 earphones in Pediatric Clinic  of Audiology Department, Faculty of Rehabilitation of Tehran University of Medical Sciences.
Results: The threshold differences between right and left ears in two test sessions, were not significantly different except for 14 KHz. HFA threshold in two test sessions showed no significant difference in all frequencies between girls and boys but 16 and 20 KHz in right ear and 10 KHz in left ear.
Conclusion : The test-retest thresholds for iudividual ears showed ±0-10 dB SPL for difference at least  in 99.74 % of ears at all frequencies that is clinically reliable and acceptable.

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Background and Aim: Auditory neuropathy (AN) can be diagnosed by abnormal auditory brainstem response (ABR), in the presence of normal cochlear  microphonic (CM) and otoacoustic emissions (OAEs).The aim of this study was to investigate the ABR and other electrodiagnostic test results of six patients suspicious to AN with problems in speech recognition.
Materials and Methods: this cross sectional study was conducted on 6 AN patients with different ages evaluated by pure tone audiometry, speech discrimition score (SDS) , immittance audiometry , electrocochleography , ABR, middle latancy response (MLR), late latency response (LLR), and OAEs.
Results: Behavioral pure tone audiometric tests showed moderate to profouned hearing loss. SDS was so poor which is not in accordance with pure tone thresholds. All patients had normal tympanogram but absent acoustic reflexes. CMs and OAEs were within normal limits. There was no contralateral suppression of OAEs. None of cases had normal ABR or MLR although LLR was recorded in 4.
Conclusion: All patients in this study are typical cases of auditory neuropathy. Despite having abnormal input, LLR remains normal that indicates differences in auditory evoked potentials related to required neural synchrony. These findings shows that auditory cortex may play a role in regulating presentation of deficient signals along auditory pathways in primary steps.

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Background and Aim:  Among all auditory assessment tools, auditory steady state response (ASSR) is a modern test. Modulation frequency for this test is usually 80 Hz. The purpose of this study, was to examined adult subjects with 40 Hz and 80 Hz ASSR and compare the results.
Materials and Methods: Thirty adult (60 ears) were evaluated by ASSR and PTA test, Results were divided into three groups: normal hearing, mild and moderate sensorineural hearing loss.
Results: In all groups, forty hertz ASSR thresholds were relatively closer to behavioral threshold than those of 80 Hz ASSR(p<0.05). Besides, the more severe hearing loss, the lower the difference between those two thresholds. Correlation coefficients were also higher in 40 Hz ASSR(p<0.05).
Conclusion: Frequency modulation thresholds with 40 Hz are more likely to be closer to the behavioral thresholds. Moreover, it has better results than the thresholds with 80 Hz.

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Background and Aim: As clinical audiometry assessment of each ear needs to know interaural attenuation (IA), the aim of this study was to investigate Persian speech IA in adults.

Methods: This cross-sectional, analytic study was performed on 50 normal hearing students (25 males, 25 females), aged 18-25 years old in Faculty of Rehabilitation, Tehran University of Medical Sciences. Speech reception threshold (SRT) was determined with descending method with and without noise. Then speech IA for Persian spondaic words was caculated with TDH-39 earphones.

Results: Mean speech IA was 53.06±3.25 dB. There was no significant difference between mean IA in males (53.88±2.93 dB) and females (52.24±3.40 dB)(p>0.05). The lowest IA was in females (45 dB) and the highest IA was in males (60 dB). Mother's language has no significant effect on speech IA.

Conclusion: We may consider 45 dB as the lowest IA for Persian speech assessment, however generalization needs more study on a larger sample.

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Background and Aim: Diabetes mellitus is a progressive metabolic disease. Studies about the relationship between diabetes mellitus and auditory impairment have shown variable results in supporting the fact that diabetes may have a complex repercussion on the auditory pathways. We aimed to evaluate hearing in patients with type II diabetes mellitus with behavioral and electrophysiological auditory tests.

Methods: In a cross-sectional study, we assessed 30 patients with type II diabetes mellitus with the mean age of 43.7 (SD: 1.3) years, ranging 40-45 years, and 30 matched healthy subjects with the mean age of 41.5 (SD: 1.5) years. Subjects were evaluated using auditory brainstem response (ABR) and pure tone audiometry. The results were compared between two groups.

Results: Pure tone audiometry was normal. There was a significant increased latency for waves I, III, and V, and also, interpeak latencies of I-III, III-V, and I-V waves (p<0.05).

Conclusion: ABR latency prolongation indicates abnormal nerve conduction velocity in patients with type II diabetes mellitus. ABR can be an important clinical tool for evaluating diabetes influence on cochlear nerve conduction velocity before hearing loss occurs in these patients.

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Background and Aim: The auditory steady state response is a modern test for estimating hearing thresholds, especially in difficult to test individuals . However, there are few bone conduction auditory steady state response data, particularly for individuals with hearing loss. The objective of this study was to investigate bone conduction auditory steady state response thresholds in individuals with sensorineural hearing loss and normal hearing.

Methods: In a cross-sectional study, 10 individuals with normal hearing and 10 with sensorineural hearing loss at the age of 15-30 years were selected by non-probability sampling. Auditory steady state response and pure tone audiometry to bone conduction stimuli in 500 and 2000 Hz were recorded in two groups. Paired and independent t-test were used to compare data between the groups.

Results: There was low correlation between bone conduction auditory steady state response and pure tone audiometry in both groups (p>0.05 for both). The difference of behavioral thresholds and auditory steady state response in 500 Hz was higher than 2000 Hz in both groups (p=0.033 for normal hearing and p=0.017 for sensorineural hearing loss groups). Comparison of these results showed significant differences between the two groups (p<0.001).

Conclusion: In both groups, there was low correlation between bone conduction auditory steady state response and pure tone audiometry thresholds. In individuals with sensorineural hearing loss and in higher frequencies , bone conduction auditory steady state response thresholds was closer to pure tone audiometery thresholds.

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Background and Aim: Diabetes mellitus is a metabolic disorder that affects multiple systems including the auditory and vestibular systems. Patients with diabetes mellitus complain of tinnitus and dizziness. The objective of this study is to assess the effects of diabetes mellitus types I and II on auditory and vestibular systems.

Methods: We compared pure-tone audiometric results and cervical vestibular evoked myogenic potentials ( cVEMPs) between 15 patients with diabetes mellitus type I (43.80 with SD 4.246), 15 patients with diabetes mellitus type II (48.13 with SD 2.973), and 10 normal volunteers (45.30 with SD 4.448). Age range of the participants was 40-50 years old.

Results: Audiometric results showed normal hearing in both types of diabetes mellitus. In contrast, comparing amplitude of cVEMPs between diabetes mellitus and control groups showed statistically significant differences (p<0.05).

Conclusion: In spite of normal audiometric results in patients with diabetes mellitus types I and II, there was abnormal vestibular responses involving vestibular end-organ and related central pathway.