Masking Release for Speech in Modulated Maskers: Electrophysiological and Behavioral Measures.
A Michelle Tanner, Emily R Spitzer, J P Hyzy and 1 others
PMID 30557224WHAT IT FOUND
In young normal-hearing adults, brain responses to a brief speech sound showed the same benefit from fluctuating noise as behavior.
Thresholds were 13.5 dB lower in fast modulated noise than in steady high-level noise, matching the 13.3 dB behavioral release.
Key findings
01The mean masking release was 13.5 dB for electrophysiological thresholds and 13.3 dB for behavioral thresholds, and the two releases did not differ.
02Electrophysiological thresholds exceeded behavioral thresholds by 6.4 dB in Steady Low, 6.4 dB in Mod Fast, and 6.6 dB in Steady High.
03Individual data showed a close association between electrophysiological and behavioral thresholds across conditions.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The findings are limited predominantly to young, normal-hearing adults, so they do not show how people outside that group would perform. Speech intelligibility was not measured, so the findings do not show that these thresholds predict speech recognition. The electrophysiological slow modulated condition was contaminated by masker-evoked responses, so only the fast modulated condition gave a usable masking-release comparison. Only 18 participants provided electrophysiological data, and the behavioral and electrophysiological groups were not the same. Electrophysiological thresholds were consistently higher than behavioral thresholds by about 6.5 dB, so a correction factor would be needed before clinical use.
Declared interests
The paper lists funding by NIH NIDCD grant 5-R01-DC001507 and no other conflicts.
The easy way to misread this
Do not conclude that cortical auditory evoked potentials can measure speech recognition or be used clinically with infants. This study tested only young normal-hearing adults, used a single /ba/ detection task, did not assess speech intelligibility, and electrophysiological thresholds were about 6.5 dB higher than behavioral thresholds.