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.

Background: hearing loss is a major health care problem that tends to retard the developmental milestones of children. It takes early detection and intervention to avoid a permanent loss in acquisition of speech and cognitive functions. Hence, the importance of hearing screening in all children especially in the developing world for accurate statistics and early intervention is clear. This work was aimed at predicting hearing in children by means of acoustic reflex measurements
Method: In this study which was performed in 1995, 146 ears(86 children aged between 5-10years old referring to audio logy clinic in Tehran university of medical sciences between august 1995 and February 1996) were evaluated (amongst 95 were normal and 51 ears with SNHL<84dB).the methods Niemeyer and Destrehan formula ,Lilly2 equation, un weighed Sensitivity prediction by acoustic reflex, weighed sensitivity prediction by acoustic reflex to establish their clinical viability.
Results: findings demonstrated that weighed sensitivity prediction by acoustic reflex(WASPAR) have a good correlation with conventional audiometric evaluation(K=.78) and also it has good sensitivity, Specificity , Negative predicted value(NPA) and positive predicted value (PPV).
Conclusion: In case that conventional audiometry is not applicable, WASPAR is a good objective choice in lieu of subjective tests.

Background: The current article is aimed at evaluating speech recognition scores in hearing aid wearers to determine whether nonsense syllables are suitable speech materials to evaluate the effectiveness of their hearing aids.
Method: Subjects were 60 children (15 males and 15 females) with bilateral moderate and moderately severe sensorineural hearing impairment who were aged between 7.7-14 years old. Gain prescription was fitted by NAL method. Then speech evaluation was performed in a quiet place with and without hearing aid by using a list of 25 monosyllable words recorded on a tape. A list was prepared for the subjects to check in the correct response. The same method was used to obtain results for normal subjects.
Results: The results revealed that the subjects using hearing aids achieved significantly higher SRS in comparison of not wearing it. Although the speech recognition ability was not compensated completely (the maximum score obtained was 60%) it was also revealed that the syllable recognition ability in the less amplified frequencies were decreased. the SRS was very higher in normal subjects (with an average of 88%).
Conclusion: It seems that Speech recognition score can prepare Audiologist with a more comprehensive method to evaluate the hearing aid benefits.

In the current investigation we gathered information about the hearing thresholds, types of hearing loss, types of tinnitus, and also the prescribed tinnitus maskers for the veterans. We were aimed at determining the percentage of tinnitus, audiogram shape and its relationship with tinnitus, and the percentages of veterans using tinnitus maskers. The needed information was prepared by studying the audiograms and file of the patients.  The results of the investigation have been prepared here in details.

We designed this study to measure the Percussion caused by pneumatic drill( 32gram) which is used commonly in different in city services. this study have been performed in the summer of 1375 in Hamedan. The results demonstrated that the average background noise level (including environment and compressor) was 92.4 with standard deviation of 5.4 dBC, the average background noise level of the drills while working was 109.6 dBC with the standard deviation of about 2.2dBC and the average peaking factor was 18.6 with a standard deviation of 3.7dBC. the average background noise level of the drills while working in a distance of 5m, 10m and 20m from the source respectively were 98.6 dBA(with a standard deviation of 2.8dBA), 91.5dBA(with a standard deviation of2.6dBA) and 86.8dBA with a standard deviation of 2.8dBA).Based on the obtained results and the potential effects of exposure to noise which mainly can be summarized to damage to auditory system, interference with the communication skills, neural excitation, Hypertension and tachycardia the side effects of noise should be taken in to account seriously.Based on the mounting evidences regarding the adverse impact of working in the noisy environment and the damaging consequences of living in such atmospheres and the findings of the current study which confirms that the noise exposure level is more than allowed limit, the health of the workers and citizens is threaded by the noise pollution factors mentioned in the current study and serious considerations should be taken in to account.

Nowadays, unwanted noise is present everywhere in the workplace and in the living environment and disturbs human peace and calm. In spite of the importance of the indirect impact of noise on human life, little is performed about this issue in our country. Therefore, the present study have been focused on the measurement of noise pollution that impose operators of the telecommunication company in addition to the evaluation of the psychological and mental effect of sound on the telecommunication operators.

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.

Sounds are the creatures of God which are found in nature in diverse forms. In addition to sounds naturally exist in the environment there are artificial sounds that is hand-maid and we experience them in our daily life. Industrialization has had detrimental effect on manufacturing such sounds in the environment which in turn can affect our mental and physical state.The current article is taking sound from a religious point of view into account. We want to discuss the role of sounds in perceiving the meanings of related concepts and also will have an overall look on the devastating effects of noise and irritating sounds on human life and the human mental and physical health.

It is as a lecture

Materials and Methods: It is for the first time in Iran that designing and construction of phase-shifter instrument for performing Masking Level Difference have been studied. For reducing limitations of MLD test in middle ear pathologies, new methods of performing MLD has been considered.
In this method noise is conducted by bone vibrator, located on forehead. The comparison between standard method and proposed method has been obtained.Forty 20-25 year-old men referring to the Faculty of Rehabilitation Science in Iran university of Medical Sciences have been tested in the period of time between 10.30.1998 to 12.21.1998.The MLD test was performed in both method at frequencies of 250, 500, 1000, 2000 & 4000 Hz.
Results: The mean of MLD results n the standard method was 11.175 dB ranging from 10 to 13 dB that is in accordance with normative data.
- There was no significant difference between the means obtained in the methods for performing MLD.
- In both methods the MLD means decreased with frequency increments.
Conclusion: It is preferable to use proposal method in middle ear disorders due to normal cochlear sensitivity and subsequently enough noise that is conducted by bone conduction (60 dB SPL).

Objectives: Introducing an approach for diagnosing the normal ABR independently or supplementary used to confirm the results of the other approaches.
Materials and Methods: This study was carried out in a descriptive manner on 31 male students of audiology in the Rehabilitation Faculty which were not chosen randomly. All of the samples aged between 18 to 25 years old with normal hearing and with no history of hearing disorder. They were tested in the winter of 1377 by ABR. The resulted of their ABR tests (62 curves) were in accordance with the convenient latency norms. After the preparation stage, the frequency analysis of the curves was considered through the Fast Fourier Transform function.
Results: considering the power and phase spectrum, three components are recognized, and phase for their frequency, amplitude and phase are determined.The normative values of the obtained amounts of the frequency, amplitude and phase for the frequency analysis results of the normal ABR curves are as follows:* First Component: Frequency: 340-530 Hz, Amplitude: 23-31 dB, Phase: 0-3 radian * Second Component: Frequency: 540-370 Hz, Amplitude: 20-30 dB, Phase: 0.3-2.7 radian * Third Component: Frequency: 750-1024 Hz, Amplitude: 19-30dB, Phase: 0-3.3 radian
onclusion: The results of the present study are exclusively valid for the society being considered, and their generalization requires more researches.

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.

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.

Studying auditory discrimination in children and the role it plays in acquiring language skills is of great importance. Also the relationship between articulation disorder and the ability to discriminate the speech sound is an important topic for speech and language researchers.Previous event- related potentials (ERPs) studies have suggested a possible participation of the visual cortex of the blind subjects were asked to discriminate 100 couple Farsi words (auditory discrimination tack) while they were listening them from recorded tape.The results showed that the blinds were able to discriminate heard material better than sighted subjects. (Prro.05)According to this study in blind subjects conical are as normally reserved for vision may be activated by other sensory modalities.This is in accordance with previous studies. We suggest that auditory cortex expands in blind humans.

Method and Materials: This research is carried out for development and evaluation of 25 phonemically balanced word lists for Persian speaking adults in two separate stages: development and evaluation.In the first stage, in order to balance the lists phonemically, frequency -of- occurrences of each 29phonems (6 vowels and 23 Consonants) of the Persian language in adults speech are determined. This section showed some significant differences between some phonemes&apos frequencies. Then, all Persian monosyllabic words extracted from the Mo ‘in Persian dictionary. The semantically difficult words were refused and the appropriate words choosed according to judgment of 5 adult native speakers of Persian with high school diploma.12 openset 25 word lists are prepared. The lists were recorded on magnetic tapes in an audio studio by a professional speaker of IRIB.In the second stage, in order to evaluate the test&aposs validity and reliability, 60 normal hearing adults (30 male, 30 female), were randomly selected and evaluated as test and retest.Findings:1- Normal hearing adults obtained 92-1 0O scores for each list at their MCL through test-retest.2- No significant difference was observed a/ in test-retest scores in each list (‘P>O.05) b/ between the lists at test or retest scores (P>0.05), c/between sex (P>0.05).
Conclusion: This research is reliable and valid, the lists are phonemically balanced and equal in difficulty and valuable for evaluation of Persian speaking adults speech recognition.

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.

Methods and Materials: Investigation of electrically evoked auditory brain stem response (EABR) is a new issue, especially in implanted patients. Experiments were performed in C.I Center of Iranian Institute for Science and research expansion,1996 on 30 implanted patients with 22 spectra and MSP cochlear implant system and 30 normal subjects with the range of 3-33 years.Findings:1- EABR was obtained in the implanted patients.2- Absolute latency of EABR waves is 1-1.5 ms shorter than ABR waves ‘P<0.05).3-Absolute latency of wave V decreases as a function of electric stimulus magnitude (P<0.05).4- No significant difference was observed in IPL Ill-V between ABR and EABR.

OAEs are sound founds in the external aditory meatus that originate in the cochlea. OAEs are generated only when the organ of corti is in near normal condition and They can be detected only when the middle ear system is operating normally. The sound generated by the cochlea are small but  potentially audible, sometimes as much as 30 dBSPL. They can emerge spontaneously in the cochlea, but more commonly OAEs follow acoustic stimulation. No electrod are needed to  observe OAEs. In fact, microphone are used to detect them.

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.