title: Effects of human middle ear muscle contractions on speech intelligibility.
abstract: The present study assessed the relationship between the acoustic reflex and speech intelligibility. Monosyllabic words mixed with noise were presented at -6, -3.0 and +3 dB signal-to-noise ratios. The word lists were presented with a 2000-Hz tone in the contralateral ear at a level 15 dB above or 20 dB below the acoustic reflex threshold to evaluate intelligibility differences with the acoustic reflex contracted and relaxed. The results indicated that a significant decrement in speech intelligibility differences with the acoustic reflex contracted and relaxed. The results indicated that a significant decrement in speech intelligibility occurred with the reflex contracted at signal-to-noise ratios of -3, and 0 dB. Slight but not significant decrements were seen at -6 and +3 dB signal-to-noise ratios. These results are discussed along with possible reasons for the lack of agreement with previous research.
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D004432:Ear, Middle / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D013060:Speech