Hearing loss, even when limited to 1 ear, has been indicated as a handicap to communication and learning. Although this does not seem true based on my clinical impressions, there are no objective data available to evaluate, or even infer, what type of hearing loss can become a true handicap to overall academic achievement. Presented herein are findings that imply, although do not prove, the potential academic handicap of unilateral hearing loss. This study prospectively analyzed the audiologic and otologic screening tests in a university over a 9-year period. The University of Tokyo is one of the leading universities in Japan the students examined undoubtedly had academic ability well above average, for the entrance examination is one of the most difficult to pass in Japan. The potential handicap to academic achievement caused by hearing impairment was evaluated by comparing the prevalence of hearing impairment among the study population

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.

In addition to Stimulus frequuncy and level, emitting Inner ear structurs status, OAEs parameters depend on conductive sound pathways charactristics, so abnormal OAEs donot always represent cochlear abnormality. Middle ear transmites Vibrations in two directions: forward and backward. Middle ear pathologies affect both forward and backward transmission.In this paper, The purpose is investigation of immediate effects of tympanic over - and under - pressure on click evoked Otoacoustic Emissions (CEOAEs) in healthy individuals. Healthy subjects with normal hearing and middle ear were exposed to ambient pressure changes in a pressure champer. The pressure was progressively changed in 100 dapa steps to accomplish on increase and decrease  in tympanic pressure. Pressure equilibration of the middle ear was avoided. The relative tympanic over-and under - pressure (+/-320 dapa) was monitored by tympanometry and CEOAEs recorded at every step of tympanic pressure change. The CEOAEs recorded during progressive tympanic over-and under- pressure had reduced amplitude and shorter latencies that were most pronounced in the 750 to 3000 Hz frequency bands.

Background and Aim: Standard tympanometry provides a valuable tool for evaluating middle ear abnormalities although it often fails to distinguish different pathologies that effect the ossicular chain. Multi-frequency tympanometry (MFT) has made it possible. The aim of the present study was to evaluate the role of MFT for distinguishing chronic middle ear pathologies.
Materials and Methods: This cross-sectional study was conducted on 60 patients. One ear was selected from each patient (60 ears) and were classified into 4 groups according to the type of their middle ear pathology adhesive otitis media middle ear effusion atelectasis and retraction pocket. The following parameters were elicited from MFT: static admittance, resonant frequency, and phase angle. The clinical results were compared with the operative findings.
Results: There is significant difference between resonant frequency and phase angle of 4 groups. No statistical correlation exists between phase angle and resonant frequency. The operative results of MFT are correlated with the operative findings.
Conclusion: The most significant parameter derived from MFT to distinguish between the 4 groups seems to be the resonant frequency.