Hearing Statement in Multiple Sclerosis: A Case Control Study Using Auditory Brainstem Responses and Otoacoustic Emissions

Multiple Sclerosis (MS) is a demyelinating disorder of Central Nervous System. It involves 8th cranial nerve and its central nuclei and is an uncommon cause of the sensorineural hearing loss. For determining the prevalence of hearing loss (HL) especially retrocochlear type in MS, a cross-sectional study was designed using Pure-Tone Audiometry (PTA), Otoacustic Emissions (OAEs), Auditory Brainstem Responses (ABRs) compared with the control group. Data were analyzed by Qui2 & Fischer exact test in SPSS 17 software. Among 60 patients (44 women & 16 men) and 38 controls (27 women & 11 men) with a mean age of 29.9±9.8 and 31.4± 8.3 years, 12.5% of case ears and 3.9% of the control ears had abnormal PTA (P= 0.043). Frequency of abnormal high frequency-PTA and two modalities of OAEs were not significantly different between case and control ears. The means of overall correlation were 75.9±23.8 in cases and 70.0±27.2 in controls (P= 0.111). 20% of case ears, and 9.2% of the control ears had abnormal ABRs (P= 0.044). The absolute latencies of waves I, II & V had not significant difference, but 10% and 11.7% of case ears and 1.3% & none of the control ears had increased inter peak latencies of I-III, and III-V respectively (P<0.05). 6.7% of case ears and 2.6% of control ears had retrocochlear abnormality (P=0.181). In conclusion, HL is more common in MS patients, especially when determined by using PTA and ABR.