Acoustic reflex and loudness discomfort in acute facial paralysis.

An extensive research protocol was used to evaluate the conditions of 48 consecutive patients with acute facial paralysis. The results indicated that after nerve excitability testing, the acoustic reflex was the most efficient indicator of impending nerve degeneration and predictor of recovery. The presence of increased sensitivity to intense acoustic stimuli (loudness discomfort level) indicated poor prognosis. The data demonstrate that dysacusis (hyperacusis) is not related to stapedial muscle paralysis and also question the validity of "topographic diagnosis" in determination of the site of the lesion in facial paralysis.