AIR- AND BONE-CONDUCTION VESTIBULAR EVOKED MYOGENIC POTENTIALS IN CHRONIC SUPPURATIVE OTITIS MEDIA, PRE- AND POST-OPERATIVELY
Mohamed I Shabana, Abeir O Dabbous, Badawy S Khalifa, Asma S Humaid
(Audiology , Cairo University, Cairo, Egypt)
JHS 2014; 4(4): OA21-35
Vestibular evoked myogenic potentials (VEMPs) are reflex myogenic potentials of the neck muscles elicited by stimulating the vestibular system with a click or tone burst sound stimulus. VEMP responses depend on good energy transfer of sound from the middle ear to the inner ear and are presumed absent in the presence of a conductive hearing loss (CHL) of more than 20 dB air-bone gap (ABG). The aim of this study was to evaluate VEMPs in patients with chronic suppurative otitis media (CSOM) before and after surgery.
Material and Methods: The study was conducted on 20 patients with CSOM preoperatively and postoperatively and on 20 controls. Their ages ranged from 20 to 50 years. Each subject underwent history taking, otologic examination, basic audiological evaluation, and air- and bone-conducted VEMP testing.
Results: All perforated ears showed a lost air conduction VEMP response pre-operatively without any post-operative improvement. This can be attributed to the absence of any statistically significant differences between the pre-operative and post-operative ABGs at all tested frequencies. Bone conduction VEMP was preserved in all CSOM cases pre-operatively and post-operatively. There were no statistically significant differences between the air conduction and bone conduction VEMP parameters in the controls except for a significantly smaller P13–N23 amplitude of bone conduction VEMP compared to air conduction VEMP. There was no statistically significant differences between the pre-operative perforated ears of CSOM cases and their controls regarding bone conduction P13, N23 latencies, or P13–N23 amplitude. There was a significantly delayed P13 latency and greater P13–N23 amplitude of bone conduction VEMP post-operatively compared to pre-operatively. But there was no statistically significant difference between pre-operative and post-operative bone conduction N23 VEMP latency or interaural amplitude difference. Bone conduction VEMP results were pre-operatively affected by the ABG and bone conduction, but not post-operatively.
Conclusions: Air conduction VEMP in patients with CSOM showed a zero-percent response rate pre-operatively that did not change post-operatively, whereas bone conduction VEMP showed a 100% response rate pre- and post-operatively. We therefore recommend using bone rather than air conduction VEMP for assessment of the sacculo-collic reflex in patients with CSOM who complain of balance problems.
Keywords: Hearing Loss, Conductive, Otitis Media, Suppurative, vestibular evoked myogenic potentials