Masking is a necessary part in ABR test the same as other Audiological experiments to obtain the real responses without the intrusion of the other ear. In the current research we are aimed at studying the effect of the masking noise on the pure latency of wave V and interwave latencies of I-III, III-V and I-V. Noise was delivered to the non test ear with intensities of 0, 30, 50 and 70 dB in four different sessions while the intensity level of the stimulus was fixed in all four sessions.

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.

Objectives: we were aimed at studying the difference in the effect of noise and pure tone on the residual inhibition in patients suffering tinnitus.
Method: patients were selected among whom referred to audiology clinic in Ran faculty of rehabilitation sciences and aged between 20-70 years old. Our method in studying patients was experimental- masking with pure tone was performed in patients who had experienced partial residual inhibition with noise.
Results the differences between the masking methods was not statistically significant.
Conclusion: it seems that no significant differences exist between the two mentioned methods in masking tinnitus.

Objectives: The current study was performed to establish the prevalence rate of hearing disorders in school age children.
Method: This study has been performed in a randomized manner among 1000 school-age children (500 girls and 500 boys) in the years between1976-1997 in Behbehan. All subjects underwent Audiometric evaluations, Otoscopy, and impedance audiometry. Additionally, parents, children and teachers were interviewed or asked by questionnaires regarding the familial status of parents, familial history of any hearing loss and the awareness of suffering hearing loss. The findings have been prepared in the charts and tables and the relationship between age and gender of the subjects with the incidence of hearing loss has been evaluated via the statistical test X² and hearing loss in left and right ear was compared by T-test.
Results: the findings demonstrated that 6.6% of the subjects suffered hearing loss in one ear (2.2%) or both ears (4.3%). 4.8% of the patients suffered conductive hearing loss while 1.6% suffered sensory-neural hearing loss. In .2% patients complained different types of hearing loss in the ears. Hearing loss was mostly slight and the relationship between age and gender with the incidence of hearing loss was not statistically significant.
Conclusion: Based on the findings we have concluded that in18.4% of the subjects, medical treatment was required and 0.7% of them were in need of rehabilitation. The percentage of the awareness of the hearing disorders among children, parents and teachers was 21.2%, 22.7% and 15.2% respectively.

Sounds situated in a certain domain of intensity can evoke auditory system physiologically. Permanent and continuous stimulation which is produced by such sounds would not be harmful to hearing organ.  This safe intensity is estimated 61 dB SPL. However one should pay attention that in case the intensity of mechanical sound wave increases (more than 75 dB SPL), the exposure time should be decreased unless the serious harm to auditory system is expected.  Auditory system can be affected due to sound harms in two major types: Permanent threshold shift and temporary threshold shift which can be described as the changes in hearing status of human caused by the exposure to sententorian sounds. Numerous physiological factors can exacerbate the devastating effects of sounds that we are aimed at an overall description on this issue in the present review article.

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.

Methods and Materials:This cross - sectional analytical study examines the clinical utility of the external ear resonance (EER) peak amplitude measurement as an index of the possible middle ear effusions. The EER peak amplitude and frequency of 180 ears in 98 children of 7-9 years old were recorded. 120 of them (30 girls & 30 boys) had normal hearing and showed type A tympanograms. The remomder (60 ear of 38 boys) showed type B tymoanograms. These children were examined at the clinic of audiology department, rehabilitation faculty, Tehran University of medical sciences and health services, year 1376 hijri.The tests included: 1) Otoscopy, 2) Pure tone air - condition test, 3)Tympanometry and 4) E.E.R peak amplitude and frequency measurement through test - retest.
Results: 1- The average of E.E.R peak frequency for normal hearing girls, normal hearing boys and hearing impaired boys is 3206 Hz (SD=564), 3202 Hz (SI)- 634) and 2953 (SD=37l) respectively.
2- The average of E.E.R peak amplitude is 16.0 dB SPL (SD=2.6), 16.6 dB SPL (SD= 3.0) and 23.5 dB (SD=3.0) for normal hearing girls, normal hearing boys and hearing impaired boys respectively.
3- The correlation of the mean of E.E.R peak amplitude and frequency for two normal groups, girls and boys, is not significant (p>0.0l).
4- The mean test/retest variability in the E.E.R peak amplitude is 16.0 dB SPL and 3.1 Hz for frequency. These results indicate high validity and consistency of E.E.R characteristics measurements.
5- E.E.R peak amplitude is significantly ccre1ated with the presence of type B tympanogram (p-0.00) we find a 6.9 dB SPL increase in average E.E.R peak amplitude in boys with type B tympanograms in comparison to boys with
type A results but correlation of average E.E.R peak frequency of two groups is significant too (p=0.00).
* The results are valid only within the context of this research.
* The results of this research have been compared with similar studies in abroad.

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.

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.

Watching a speaker's lips is like hearing speech by eye instead of by ear and markedly improves speech perception. In this review I summarise studies over the last sixty years about lip reading, it's issues, methodological problems, experimental and co relational studies, issues of cerebral lateralization, localization and cognitive and neuro psychologic function. Several studies on speech reading in general suggest that hearing impaired groups actually do not possess superior speech reading skills compared to normal controls. With function magnetic resonance imaging (FMRI) it was also found that the linguistic visual cues are sufficient to activate auditory cortex in the absence of auditory speech sounds. Here I presented data and arguments about all aspects of the phenomenon of lip reading and it's use in rehabilitation audio logy

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.

Background and Aim: Oral stereognosis is the ability to recognize the objects placed in the mouth this plays a significant role in speech sounds production. Since the children with hearing loss have articulation disorders, this study aimed to clear the relation of hearing loss degrees and oral stereognosis in 5-year-old children.
Methods: In this cross-sectional non-invasive study, 40 children of 5-year-old (30 children with different degrees of hearing loss and 10 normal children) were involved. Oral steriognostic test was done for all of them and the Mann-Whitney U was used for statistical analysis.
Results: There were significant differences between the mean of oral stereognostic ability between the normal children and the children with severe (p<0.01) or profound hearing loss (p=0.05). There was no significant difference between the mean of oral stereognostic ability among the children with moderate, severe and profound hearing loss compared with together. Besides, there was no significant difference between the mean of the time of diagnosis among all of hearing loss and normal children.
Conclusion: The study shows that the children with moderate, severe and profound hearing loss have inefficient oral stereognosis in comparison with the normal children.

Background and Aim: Conversational repair skills are essential for establishing mutually successful verbal communication. Cognitive and linguistic disorders can have negative effects on these skills. Children with hearing loss have special cognitive and linguistic issues. This study was performed to contribute to the paucity of data on conversational repair strategies used by hearing impaired children.

Methods: The participants included 58 children with moderate hearing loss (38 boys and 20 girls) aged 6 to 7 from Ahvaz city. A cross-sectional study design was used. Frequency of using different types of repair strategies in ten repair situations was calculated. Scores of intelligence, memory, word finding, lexical richness, and mean length of sentences was obtained through cognitive-linguistic tests. Data was analyzed employing an independent t-test, Pearson correlation coefficient, and logistic regression.

Results: A direct correlation was observed between clarification strategy and communicative social intelligence (p=0.045). A direct correlation was observed between applying different types of conversational repair strategies and linguistic abilities in children with moderate hearing loss (p<0.05).

Conclusion: Children with moderate hearing loss (age: 6-7 years) use repetition more than any other strategy to repair conversation. One unit increase in word finding ability or in mean length of sentence predicts one unit increase in the degree of using repetition strategy.