[ comparison study of contralateral transient evoked otoacoustic emission [TEOAE] suppression in normal hearing subjects and multiple sclerosis patients]

A common auditory complaint of multiple sclerosis patients, is misunderstanding speech in the presence of background noise. Evidence from animal and human studies has suggested that the medial olivocochlear bundle may play an important role in hearing noise. The medial olivocochlear bundle function can be evaluated by the suppression effect of transient otoacoustic emission in response to contralateral acoustic stimulation. The present study was conducted to investigate the suppression effect of transient otoacoustic emission in multiple sclerosis patients. This analytical case-control study was conducted on 34 multiple sclerosis patients [24 female, 10 male], aged 20-50 years and 34 controls matched for age and gender in Faculty of Rehabilitation, Tehran University of Medical Sciences in 2006. All cases were selected in simple random manner. The suppression effect of transient otoacoustic emission was evaluated by comparing the transient otoacoustic emission levels with and without contralateral acoustic stimulation. Data were analyzed using SPSS software and independent T- test. There was no significant difference in transient otoacoustic emission levels of two groups, but a significantly reduced suppression effect of transient otoacoustic emission was found in multiple sclerosis patients, in compare with the controls. Outer hair cells activity in multiple sclerosis patients was normal but these patients presented low activity of the medial olivocochlear bundle system which could affect their ability to hear in the presence of background noise

[ comparison study on latency and amplitude of auditory brainstem response and auditory middle latency response in patients with multiple sclerosis and in healthy control group aged between 20 to 50 years old]

Multiple Sclerosis [MS] is a neurological disorder that involves CNS. Researches indicated that Auditory Brainstem Response [ABR] and Auditory Middle Latency Response [AMLR] in MS disorder show some changes and can be used as diagnostic tests. So, the purpose of this study is to measure and compare the latency and Amplitude of ABR and AMLR waves in MS patients aged between 20-50 years. This cross sectional descriptive-analytic and non-intervention study were conducted on 31 MS patients and 34 normal cases aged 20-50 years. ABR and AMLR were performed on each case. Then amplitude and latency of waves were studied. The mean latency of waves III, V [ABR], Na [AMLR] and Amplitude Ratio of V/I showed significant difference in both groups but comparing I [ABR] and Pa, Nb [AMLR] and amplitude of Na, Pa and Nb waves in two groups didn't show any significant difference. 70% of MS Patients in ABR test and 50% in AMLR test showed some kind of disorders in one or more waves. Using ABR test can help more in diagnosis process of MS in comparison with AMLR test