Method and Materials :this cross sectional descriptive and analytic survey was done at Golestan navy hospital in Tehran, between June 1998 and March 1999 on total of 69 male subject (104 ears, ) 50 acoustic trauma & 54 noise induced H.L) between 20 to 40 ears old.
Results:1- The mean acoustic reflex threshold at 1 kHz showed there is no significant difference between two groups.
2- The intensity elicited maximum reflex amplitude at 1 kHz didn&apost produce at a significant linear correlation with subject&aposs age and ear canal volume in both groups.
3- The intensity elicited maximum reflex amplitude in NIHL group wasn&apost shown a significant correlation with ear compliance and gradient.
4- The mean Intensity (SPL) elicited maximum reflex amplitude in NIHL group was more than mean intensity (SPL) in acoustic trauma group.
5- The mean intensity (SL) elicited maximum reflex amplitude in NIHL group was More than mean intensity (SL) in acoustic trauma group.
Conclusion: Acoustic reflex amplitude is reduced for subjects with NIHL compared with acoustic trauma subjects.

Rehabilitation of deaf individual is one of the important subjects that has attracted attention of many researchers during past centuries. Different opinions have been established in this direction. Electrophysiologic tests were established and developed parallel to developments in rehabilitation. Therefore, opinion of using electrophysiologic test for evaluation and fitting of hearing aid became gradually popular. Ultimately, the electrophysiologic tests are used in evaluation and fitting of hearing aid in two ways:1-Direct way2- Indirect wayIn direct way aided ABR is obtained and special attention is paid to wave V. This technique has many difficulties. Inindirect way, electrophysiologic tests such, ECochG, OAE and ABR, AMLR, ALR and P300 and other objective tests are used, especially in infants and neonates for evaluating the state of hearing. Researches are continuing in this field. It is probable to have aided electrophysiologic responses with speech stimuli in near future.

Binaural hearing is an important phenomenon in hearing for human being. Nowadays, the role of binaural hearing in the process of amplification has been focused. Since hearing aids act separately in the process of amplification and hearing, the attentions has been devoted to designing a system for binaural amplification by means of Beam forming which will be explained in more details in the current article.

Recent studies have been ocused on designing an intelligent system containing binaural fitting. Researchers are mostly aimed at seperating signals from background noise and other disturbing signals. most of such techniques include Digital Signal Processing(DSP). Here we will have a look in this technique.

Background: In recent years there has been increased interest in the use of Al for assessing hearing handicap and for measuring the potential effectiveness of amplification system.AI is an expression of proportion of average speech signal that is audible to a given patient, and it can vary between 0.0 to 1.0.
Method and Materials: This cross-sectional analytical study was carried out in department of audiology, rehabilitation, faculty, IUMS form 31 Oct 98 to 7 March 1999, on 40 normal hearing persons (80 ears 19 males and 21 females) and 40 hearing impaired persons (61 ears 36 males and 25 females, 25-65 years old) with moderate to moderately severe SNI-IL The pavlovic procedure (1988) for calculating Al, open set taped standard mono syllabic word lists, and the real -ear probe- tube microphone system to measure insertion gain were used, through test-retest.
Results: 1/A significant correlation was shown between the Al scores and the speech recognition scores of normal hearing and hearing-impaired group with and without the hearing aid (P<0.05) 2/ There was no significant differences in age group & sex: also 3 In test-retest measures of the insertion gain in each test and 4/No significant in test-retest of speech recognition test score.
Conclusion: According to these results the Al can predict the unaided and aided monosyllabic recognition test scores very well, and age and sex variables have no effect on its ability. Therefore with respect to high reliability of the Al results and its simplicity, easy -to- use, cost effective, and little time consuming for calculation, it&aposs recommended the wide use of the Al, especially in clinical situation.

Method and Materials: This cross- sectional analytical survey is carried out in department of audiology, rehabilitation faculty, IUMS, 1997-1998 on 10 normal and 28 sensory damaged ears out of 27,8 to 40 years old male individuals were evaluated according to following critria:Hearing threshold up to 7OdBHL.Normal middle ear status.
Results: There is good correlation between kiessling&aposs procedure and R-N.A.L, P.O.G.O 11 and Lyharger procedures in determining gain of hearing aid in individuals with flat and raising audiogram. There is poor correlation between them in individuals with high frequency sensory hearing loss.
Conclusion: Kiessling&aposs procedure can he used instead of Lyharger, R-N.A.L, P.0.0.0 11 procedures in children, difficult to test and multihandicapped persons who are not able to cooperate in behavioral audiometry.

We expect some people benefit more from their hearing aids, but after a while they complain of inappropriate loudness growth.  Currently fitting hearing aids based on their loudness growth curves one of the best and most acceptable ways of fitting hearing aids we should study this curve based on the disturbed function of inner and outer hair cells. We should also know that based on which curves can make the growth curve of the damaged cells to normal ones.

In order to develop oral communication, hearing impaired infants and young children must be able to hear speech comfortably and consistently. To day children with all degrees of hearing loss may be condidates for some kinds of amlification.As children differ from adults, many Factors should be consider in hearing aid selection, evaluation and fitting. For example the child age when he or she is candidate for custom instruments? Do we consider programmable Hearing aid? Are multi memory instruments appropriate for them? What about directional microphones? What style of hearing aid do we select? In this paper such questions are responded.

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.

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.

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.

Objective: A research was conducted to assess the phonological awareness in hearing-impaired children in comparison to normal children. In this context, we discussed about the ability of these children in identification of rhyme and word segmentation to syllables.
Method and Material: The sample of this study is composed of 320 children, 160 normal & 160 hearing-impaired with a hearing-loss. Of over 70 dB, studying in the 1st t 4th grade of the primary schools in Tehran. They are divided into two groups at each level (20 girls & 20 boys).
Results: 1) Hearing-impaired children&aposs scores on test related to rhyme and syllable is lower as compared with normal children. 2) Hearing-impaired children are more potent on test of word segmentation to syllables in comparison to that related to rhyme, while normal children are more successful on test of word segmentation to syllables as compared with that related to rhyme.

Discussion: Hearing is an important factor in phonological awareness. Formal education at special schools doesn&apost compensate for the hearing impairment as to development of the phonological awareness.

Objective: A survey on hearing state of blind schoolboys in Tehran.
Method and Material: This cross-sectional descriptive survey was conducted on 640 ears of 320 blind schoolboys of 5-23 years old as a hearing screening in Tehran blind schools, 2000-01.
Results: 20.94% was hearing-impaired of whom 13.75% had bilateral and 7.19% had unilateral hearing loss. 15.16% of students suffered from sensory-neural hearing loss (SNHL), 1.56% from conductive hearing loss (CHL) and 0.62% from mixed hearing loss (MHL), that is, SNHL occurred 10 times more than CHL. Hearing loss was often mild and moderate, and audiogram configuration was primarily high tone loss (HTL). On the whole, 8.13% of students needed medical treatment, 15.13% needed audiological rehabilitation and 3.44% of them were in need of both medical and rehabilitation Intervention. General information about hearing problem was very low among students, their parents and teachers, which was 26.87%, 20.9% and 22.39%, respectively. There is significant relation between SNHL and parents&apos relationship.
Conclusion: The prevalence of hearing loss in blinds is higher than in normal-visions. It is often sensorineural. So, it is important to identify these children through hearing screening (Using more high frequencies) and to conduct medical as well as rehabilitative intervention.

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.

Objective: To determine SOAE,TEOAE, and DPOAE, characteristics in normal -hearing school boys.
Method and Material: This cross-sectional study was conducted on 7-11 year-old normal -hearing boys (n = 100) living in 12th zone of Tehran. OAEs also performed and investigated if otoscopy, pure tone and immittance audiometry were normal. Both handedness and ear effects was also considered.
Results : 31% had SOAEs. No significant differrence between the right and lefe ear SOAEs frequency and amplitude means. 1,3 kHz and total response TEOAEs amplitude was significantly different between two ears. There was no significant difference between both ear DPOAEs amplitudes, whereas the letf-handed boys&apos DPOAE amplitude is greater than the right -handed ones&apos amplitudes.
Conclusion : As some results including equal SOAEs of both ears , no difference between both ears SPOAEs amplitude , and handedness effect on the amplitude do not agree with other studies , these finding should be considered in testing OAEs of school boys.

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.

Objective: Survery and comparison between the physical characteristics of Distortion-Product Otoacoustic Emissions of 1-59 day-old normal-hearing newborns refered to TUMS, Rehabilitation School , Audiology department , 2002
Method & Material : This analytical-descriptive study was conducted on the ears of 102 easy method selected newborns. The tests included: otoscopy , BOA, Immittance audiometry , DPOAEs, and ABR if necessary. The amplitude and frequency of 2f1-f2 emissions of DPOAEs evoked by two pure tones (L1=65 dBSPL , L2=50 dBSPL and f2/f1=1.2) were also calculated.
Results: 1-All normal hearing newborns have normal DPOAEs. No significant difference was observed in test-retest. 2- The amplitude of the DPOAEs to the right ear is significantly greater than the amplitude of the left ear (P<00.05). 3- No significant difference was observed between newborn&aposs DPOAEs in terms of their gender.
Conclusion: DPOAEs could be measured quickly and noninvasively and are excellent tools for the screening of newborn hearing loss. The results are valid only within the Context of this research.

Objective: Comparing analog and digital hearing aids reducing disability caused by hearing deficiency among moderate to severe sensorineural hearing-impaired persons.
Method and Material: This descriptive-analytic study was carried out on two groups of subjects participated in this study in some audiology clinics of hearing aid since May 2002 to October 2003. Twenty subjects wore analog hearing aids and twenty one subjects wore digital hearing aids. In this study , no subject had previous middle ear or psychological problems. APHAB questionnaire was completed before using hearing aid and 2 months after to determine benefit of hearing aid use. Results: Total score mean of APHAB inventory before and after use of analoge hearing aids were 52.215+6.420 and 32.300+3.443 respectively. Also total score mean of APHAB inventory before and after use of digital hearing aids were 54.9252+9.028 and 26.321+10.916 respectively. There was no significant difference between total mean score of APHAB inventory before and after using analog and digital hearing aids (P=0.058).While there was significant difference between total mean score of APHAB questionnaire before and after use of analog hearing aids (P<0.001) and also before and after use of digital hearing aids (P<0.001). Moreover age, gender , litracy level , occupation , degree of hearing loss and manner of hearing aid usage did not have significant effect on APHAB results. Configuration of loss had siginficant effect on aversiveness subscale before and after use of analog hearing aids (P=0.008). Previous experience and duration of hearing aid usage had significant effect on aversiveness subscale before and after use of digital hearing aids (P=0.043) and (P=0.024), respectively , while all of these three items did not have significant effect on total mean score of APHAB inventory and also total mean scores of three subscales of ease of communication , reverberation and background noise.
Conclusion: Comparing to analog hearing aid , digital one is significantly benefitial for reverberation and background noise for hearing-impaired persons , but it has no benefit for ease of communication and aversiveness that may be arised from effects of the individual expectation , psychological and personal factors.

Objective: Genetic studies show that consanguineous marriage can increase the probability of incidence of genetic impairments such as hearing impairments. The target of this study is to identify the prevalence of consanguinity among the parents of hearing impaired students in primary schools.

Materials and Methods: We selected all of deaf students of Tehran (614 students). Their mothers answered to questionnaires. The questions were about Risk Factors of deafness in mother pregnancy or in neonatal period.
Results: from 614 students, 389 parents of them (64%) had consanguineous marriage and 223 person (36%) didn&apost have this factor. 2 person did not answer to this question. In this study we observed that there is 32.3% family history of hearing loss, 29.2%deaf sister and brother, 17% ear infection history. Other risk factors were studied too. Also there is significant correlation between consanguinity and more than one deaf children in the family (p<0.005).
Conclusion: According to high incidence of consanguinity (64%)that was observed in this study it may be one of most important causes of sensory neural hearing loss in children, so we should give enough information about this problem to the people.

Objective: Noise measurement and frequency analysis of commercially available noisy toys were the main purposes of the study.
Materials and Methods: 181 noisy toys commonly found in toy stores in different zones of Tehran were selected and categorized into 10 groups. Noise measurement were done at 2, 25, and 50 cm from toys in dBA. The noisiest toy of each group was frequency analyzed in octave bands.
Results: The highest and the lowest intensity levels belonged to the gun (mean=112 dBA and range of 100-127 dBA) and to the rattle-box (mean=84 dBA and range of 74-95 dBA), respectively. Noise intensity levels significantly decreased with increasing distance except for two toys. Noise frequency analysis indicated energy in effective hearing frequencies. Most of the toys energies were in the middle and high frequency region.
Conclusion: As intensity level of the toys is considerable, mostly more than 90 dBA, and also their energy exist in the middle and high frequency region, toys should be considered as a cause of the hearing impairment.