Evaluation of cochlear function in a patient with "far-advanced" otosclerosis.

A patient with "far-advanced" otosclerosis with a profound bilateral hearing loss was evaluated for cochlear reserve using transtympanic electrocochleography (ECoG) and promontory stimulation. Results indicated that both ECoG and promontory responses were present, indicating that cochlear function was present bilaterally. A stapedectomy resulted in closure of the air-bone gap. Postoperative hearing yielded excellent aided responses compared to no measurable preoperative hearing aid benefit. This case serves to demonstrate the value of evaluating cochlear function using these electrophysiologic techniques.