In this article we aimed at studying the function of Melanin in the inner ear. To reach this goal TTS was studied in people with blue or brown eye color. Subjects were 68 male teenagers with normal hearing. Auditory thresholds were obtained by means of high frequency audiometry (.8-8KHz)before and after TTS.  We used narrowband noise with frequency width of 1665-2335Hz, central frequency of 2 KHz, intensity of 105dBSPL and duration of 10 minutes. A significant difference was discovered in the average TTS of this two group in the frequency range of 2-8 KHz. Brown-colored eye boys manifested the least TTS and the blue- colored eyes one the most discovered TTS.

Many researchers have reported that after the sound trauma, RNA and DNA in the outer hair cells and ganglion cells will decrease. Some scientists have also mentioned the mitochondrial enzyme deficits in cochlear cells. Sound stimulation will induce the decrease of enzyme activities which are effective in the process of energy production. This process happens because of the reduced ATP synthesis and in turn the damage to receptors due to energy disruption.  The moderate oxygen deficiency can also be considered as a potential factor in the amplitude changes of the potential of cochlear microphonic due to irrita6ing sounds. On the other hand, since the organ of corti is far from blood tissue, logically, Anaerobic Glycogen should be considered as the main factor in the metabolism of the organ of corti.In addition to that, there are evidences which demonstrate intense acoustical stimulation can increase Na+ and decrease K+ in endolymphatic fluid and a contrary effect in perylimphatic fluid in scala vestibule.

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 & 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.

Method & Material: This study examined the speech in noise test in 60 school age children with otitis media with effusion and 30 school age children with normal hearing in +5, 0 and -5 dB signal to noise ratio. The mean of age was 8.05 in study group and 8.25 in control group. Speech in noise test were performed for study group and control group in quiet an in noise. Speech noise presented ipsilaterally in both groups.Finding: The correlation of mean of SDS in +5, 0 and -5 dB signal to noise ratio between study group and control group, is significant.

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.

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.

Background and Aim: Analysis of transient evoked otoacoustic emissions(TEOAEs) is of considerable interest due to their close relation with cochlear mechanisms which reveal cochlear function.The particular structure of TEOAEs requires a method with both a satisfactory time and frequency resolution. Among different methods the time –frequency techniques are the most suitable approaches. The aim of this study was to investigate the differences between neonate’s cochlear function and adult’s cochlear function using time –frequency approaches in TEOAEs.

Materials and Method: The data of this cohort study was obtained from a sample of 23 normal neonates, aged between 1-28 days, and 31 normal adults, aged between 18 -25 years.TEOAEs with click stimulus were performed for both ears .The TEOAEs files were investigated in time – frequency transform software in off-line mode. The signal to noise ratio(SNR) and response level (dB) of TEOAEs were analysed.

Results: The reproducibility, SNR and response level in neonates was greater than adults and in both groups there were no significant difference between responses of males and females and of the right and the left ears.

Concolusion: There are differences between neonate’s and adult’s cochlear response. High frequencies responses are stronger in neonate’s cochlea.

Background and Aim: Internal Evaluation means assessment of abilities and potentials. To promote the quality of education, research, health and finally rehabilitation is one of the most important roles and responsibilities of the universities. Promotion of quality of the theoretical and practical education for the Audiology students provides this major with its final goal that is to serve society. The purpose of this study was to evaluate the strength, weaknesses, opportunities and threats (SWOTs) of the Audiology department and to identify the ways of diminishing weaknesses and threats.
Materials and Methods: This descriptive cross-sectional study was conducted on undergraduates, postgraduates, graduates, academic staff, and the director of Audiology department in 9 areas, including management flowchart, educational programs, instructional methods and curriculum models, students, educational areas and equipments, graduate, academic staff, research, and treatment. Data were collected by questionnaires. Results were analyzed descriptively and were expressed in raw and percentage.
Results: The scores of areas in two measures were as follows: management flowchart 4.36 (87.31%), educational programs 4.17 (83.58%), instructional methods and curriculum models 4.01 (80.26%), students 3.43 (68.60%), educational areas and equipment 3.60 (72.11%), from the view of undergraduates, post graduates, faculties, graduates 3.60 (72.03%), academic staff 4.03 (80.6%), research 3.52 (70.4%), and treatment 4.54 (90.80%). The highest score was, therefore, of the treatment area and the lowest belonged to the educational area and equipments. The score of the Audiology department, as the main factor was 3.89 out of 5 which was 77.88%.
Conclusion: Audiology group total score indicates the desirable status that can be promoted to the most desirable if SWOTs are considered.