Stapedius reflex and speech features

Articulation scores and stapedius reflex responses to the same speech phrases were determined in subjects with unilateral stapedius muscle paralysis. Understanding of the speech sounds deteriorated significantly for maximal levels above 100 dB SPL, which was just above the threshold for the stapedius reflex. We conclude that the stapedius muscle extends the dynamic range of the ear by 15–20 dB.