Spontaneous otoacoustic emissions reveal an efficient auditory efferent network

Purpose: Understanding speech often involves processing quiet. This reduced amplification may aid in the perception input from multiple modalities. The availability of visual of speech by improving the signal-to-noise ratio. Critically, information may make auditory input less critical for there was a greater reduction in amplification when speech comprehension. This study examines whether the auditory sounds were presented bimodally with visual information system is sensitive to the presence of complementary relative to when they were presented unimodally. This effect sources of input when exerting top-down control over the was evidenced by greater changes in SOAE levels from amplification of speech stimuli. baseline to stimuli presentation in audiovisual trials relative Method: Auditory gain in the cochlea was assessed by to audio-only trials. monitoring spontaneous otoacoustic emissions (SOAEs), which Conclusions: The results suggest that even the earliest are by-products of the amplification process. SOAEs were stages of speech comprehension are modulated by top-down recorded while 32 participants (23 women, nine men; M_age = 21.13) influences, resulting in changes to SOAEs depending identified speech sounds such as “ba” and “ga.” The speech on the presence of bimodal or unimodal input. Neural sounds were presented either alone or with complementary processes responsible for changes in cochlear function are visual input, as well as in quiet or with 6-talker babble. sensitive to redundancy across auditory and visual input Results: Analyses revealed that there was a greater reduction channels and coordinate activity to maximize efficiency in in the amplification of noisy auditory stimuli compared with the auditory periphery.