Brainstem auditory evoked potentials and electrocochleographic findings in patients with idiopathic sudden sensorineural hearing loss.

OBJECTIVE To determine the status of cochlea, auditory pathway and hearing threshold by recording brainstem auditory evoked potential (BAEP) and electrocochleography in patients with idiopathic sudden sensorineural hearing loss (ISSNHL). STUDY DESIGN Observational study. PLACE AND DURATION OF STUDY Department of Clinical Physiology at King Abdul Aziz University Hospital, Riyadh, Saudi Arabia, from May 2002 to November 2007. METHODOLOGY Patients diagnosed with idiopathic sudden sensorineural hearing loss (ISSNHL) based on clinical features and pure tone audiometry were studied. Brainstem auditory evoked potential (BAEP) and electrocochleography (ECOG) was performed in them according to standard protocols for assessment of auditory pathway and hearing threshold. RESULTS Out of 23 patients (14 males and 9 females) left ear was affected in 9 (39.1%) patients, right ear in 13 (56.5%) and both in 1 (4.3%). Absolute latency of wave I and wave V were significantly prolonged in affected ear compared to unaffected ears (p=0.0031), while interpeak I-V latency was significantly higher in affected ears versus unaffected ears (p=0.0544). Six patients (26.1%) had type II Diabetes mellitus, five cases (21.7%) had hypertension and 5 cases (21.7%) had dyslipidemia. ECOG revealed absence of summation potential (SP) and action potential (AP) response even at 95 dB in 17 out of 23 cases (73.9%). CONCLUSION Patients with ISSNHL had significant abnormalities in BAEP and ECOG recordings showing predominantly cochlear involvement. Thus, these tests provide useful diagnostic information in patients with ISSNHL in addition to pure tone audiometry.