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Since common audiometric evaluations are performed by subjective tests in which patient&aposs cooperation is required, the importance of systems which are made to obtain auditory evoked potentials in infants, young children and difficult-to- test patients can be accentuated. This article firstly refers to the theory of the mechanism and function used in designing the auditory evoked potentials systems and then the procedure of planning and producing this instrument is explained.

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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.

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Many pregnant women are exposed to noise in the workplace. Noise can affect both fetus and pregnancy of pregnant women. Hormonal disturbances and nanism are of devastating effects of noise. An increased risk of shortened gestation has been shown in four studies Results. In a third study showed the length of gestation in female infants to be inversely correlated to maternal residential noise exposure. Decreased birth weight has also been associated with noise exposure in pregnant women.Some of the adverse impacts of exposure to noise is discussed here as an investigation report.

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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.

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Objective: Comparison of Air conduction (AC) and Bone conduction (BC) auditory brain stem response (ABR) latencies.
Materials and Methods: In this cross-sectional study, 34 (17 males, 17 females) normal-hearing young subjects tested with AC- and BC-ABR .Wave V latencies of both procedures were compared
Results: BC- wave V latency significantly prolonged about 0.5 ms. That prolongation was less with decreasing intensity. Females&apos AC-and BC - ABR latencies were less than males&apos.
Conclusion: AC- and BC- ABR appeared to be useful to determine sensory-neural acuity in children with atresia or difficult to test subjects specially newborns.

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Background and Aim: Diabetes mellitus is a progressive metabolic disease. Studies about the relationship between diabetes mellitus and auditory impairment have shown variable results in supporting the fact that diabetes may have a complex repercussion on the auditory pathways. We aimed to evaluate hearing in patients with type II diabetes mellitus with behavioral and electrophysiological auditory tests.

Methods: In a cross-sectional study, we assessed 30 patients with type II diabetes mellitus with the mean age of 43.7 (SD: 1.3) years, ranging 40-45 years, and 30 matched healthy subjects with the mean age of 41.5 (SD: 1.5) years. Subjects were evaluated using auditory brainstem response (ABR) and pure tone audiometry. The results were compared between two groups.

Results: Pure tone audiometry was normal. There was a significant increased latency for waves I, III, and V, and also, interpeak latencies of I-III, III-V, and I-V waves (p<0.05).

Conclusion: ABR latency prolongation indicates abnormal nerve conduction velocity in patients with type II diabetes mellitus. ABR can be an important clinical tool for evaluating diabetes influence on cochlear nerve conduction velocity before hearing loss occurs in these patients.

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Background and Aim: Studies have shown that long-term use of monaural hearing aid in symmetrical hearing losses may lead to physiological changes. In this research, the possibility of plasticity occurrence in bilaterally hearing impaired listeners fitted with only one hearing aid was investigated.

Methods: Our study was carried out on 12 elderly listeners with a mean age of 61.92 years who had symmetrical moderate to severe sensory neural hearing loss in both ears. All of the participants had minimum monaural hearing aid experience of 2 years. We used auditory brainstem response (ABR) testing in order to compare absolute latency and amplitude of wave V between the two ears of cases. Air conduction click stimuli were presented monaurally at 80, 90 and 100 dB nHL.

Results: Despite the shorter absolute latency of wave V in the fitted ear, no significant difference was found between the two ears (p>0.389). The difference between wave V amplitude of both ears was greater in 90 dB nHL level (p=0.043). Women showed shorter mean latency than men and the mean amplitude of women was greater than men. Significant gender difference was observed in absolute latency of wave V (p<0.037).

Conclusion: Our findings indicate that the use of monaural hearing aid in symmetrical hearing losses can induce neural plasticity within auditory brainstem pathways which can be displayed by auditory brainstem response test.