Changes in loudness after stapedectomy.

Abstract

Twenty subjects who had undergone unilateral stapedectomy and three subjects suffering from unilateral Bell palsy were tested to determine (1) the presence of phonophobia by means of the loudness discomfort levels (LDL) and threshold of the acoustic reflex, where measurable, (2) changes in loudness function by means of alternate binaural loudness balance (ABLB) measures, and (3) presence of distortion at high intensity levels (overload) by means of speech discrimination scores at high intensity levels. Both groups responded similarly in that many, but not all patients demonstrated (1) no change in LDL to pure tones but 5 to 8 dB lowering of LDL in the affected ear for speech; (2) unusual changes in loudness perception at suprathreshold levels only; and (3) decrease (rollover) in discrimination scores at high intensity levels in the affected ear.