Abstract
Subjects with unliateral Bell's palsy and stapedius muscle paralysis in one ear and normal stapedius reflex in the other were exposed to narrow band noise with the center frequencies 0.5 and 2.0 kHz at several intensities. There was significantly greater temporary threshold shift (TTS) in the affected ear than in the unaffected ear after the 0.5 kHz noise at and above 110 dB SPL. A difference was already present after 100 dB SPL noise exposure. After the 2.0 kHz noise there was no such difference. We conclude that the stapedius reflex in man may protect the ear aginst auditory fatigue, probably also against permanent injury within the low frequency region