The Influence of Cochlear Mechanical Dysfunction, Temporal Processing Deficits, and Age on the Intelligibility of Audible Speech in Noise for Hearing-Impaired Listeners.

This was an observational study of associations, not a test of whether treating any one measure would improve speech in noise. Cochlear gain loss and residual compression were inferred indirectly from behavioral tests and assumptions, so they are not direct measurements of the inner ear. Temporal processing was measured only at 1500 Hz, so it may not represent how listeners process all speech frequencies. Participants were hearing-aid users or candidates and had losses suitable for estimating cochlear gain loss, so the sample may not represent all people with hearing loss. The models left much of the score differences unexplained: each final model explained 39% of the variance. Age was not correlated with pure-tone thresholds in this sample, which was unexpected and may reflect the selected hearing-loss range.

Do not read the regression models as proof that any single measure causes speech-in-noise difficulty. This was an observational study, and cochlear gain loss did not add predictive value once other variables were included.