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. Author manuscript; available in PMC: 2022 Jun 26.
Published in final edited form as: Nat Biomed Eng. 2021 May 3;6(6):717–730. doi: 10.1038/s41551-021-00707-y

Fig. 7. Amplification decreases consonant identification even with normal hearing.

Fig. 7

a, Performance of a support-vector-machine classifier trained to identify consonants based on population single-trial responses to speech at 62 dB SPL. Results are shown for normal hearing gerbils without (NH) and with (NH+20dB) linear amplification (values for each population are shown along with mean ± 95% confidence intervals derived from bootstrap resampling across populations) for three conditions: speech in quiet, speech in the presence of ongoing speech from a second talker at equal intensity, and speech in the presence of multi-talker babble noise at equal intensity. b, Magnitude of different response components for single-unit responses to speech at 62 dB SPL in multi-talker babble noise (mean ± 95% confidence intervals derived from bootstrap resampling across neurons). c, Performance of a support-vector-machine classifier trained to identify consonants based on population single-trial responses to speech in noise at 62 dB SPL with linear amplification. Results are shown for normal hearing gerbils (NH+20dB) and gerbils with hearing loss (HL+20dB), presented as in a. d, Schematic showing the effects of intensity on speech intelligibility with and without hearing loss and amplification. The range of intensities of typical speech is shown in gray. Left, The loss of intelligibility with hearing loss that results from the loss of audibility without amplification. Right, The loss of intelligibility with hearing loss that results from rollover with amplification.