The role of auditory evoked potentials and otoacoustic emissions in early detection of hearing abnormalities in Behçet's disease patients. A case control study.

Objectives: To determine the types and to assess the role of auditory evoked potentials and otoacoustic emissions in early detection of hearing abnormalities in Behçet's disease (BD) patients. Their correlations with disease activity were also considered.
Methods: Thirty patients with BD and thirty apparently sex- and age-matched healthy volunteers were included in this study. Auditory evaluation included pure tone audiometry (PTA), otoacoustic emissions (TEOAEs, DPOAE), auditory brainstem response test (ABR) and cortical auditory evoked potentials (tone and speech CAEPs) for all patients and control.
Results: The highest abnormality of CAEP latencies elicited by (500Hz and 1000 Hz) as well as speech stimuli (da and ga) among our BD patients was delayed P1 and N1 waves at 80 dB with greater bilateral affection, as well as significant differences between patients and controls. All our BD patients had a smaller amplitude of distortion product OAE (DPOAE) and S/N ratio at 1, 2, 4, 6 kHZ compared with controls and the differences were highly statistically significant (p=0.0001).
Conclusions: Being one of the autoimmune inner ear diseases (AIED), BD has a definite hearing impairment, even in the presence of normal hearing sensitivity, as evidenced by PTA. BD patients had a sub-clinical cochlear pathology which was not affected by disease activity or different organ affection. DPOAE (S/N ratio) proved to be a sensitive test in detecting minimal changes in cochlear pathology and the latencies of CAEPs (tone and speech) measures were considered as sensitive indicators (100%) of early detection of hearing impairment in BD patients.