Will diminishing cochlear delay affect speech perception in noise?
OBJECTIVE
Normal auditory systems appear well habituated to time/phase delays inherent to sound encoding along the hearing organ, sending frequency information non-simultaneously to the central auditory system. Eliminating, or simply perturbing, the cochlear delay might be expected to decrease speech recognition ability, especially under demanding listening conditions. Resources of a larger-scale investigation permitted a preliminary examination of this issue, particularly on a relevant timescale of empirically demonstrated cochlear delays.


METHODS
In a randomized controlled trial study, word recognition was tested for mono-syllabic tokens treated digitally to exacerbate, if not diminish/nullify, such delays. Speech-weighted noise was used to interfere with listening to time-frequency reversed (nominally no delay) versus non-reversed (natural timing) transforms under three treatments of speech tokens: (1) original-digitally recorded; digitally processed to emphasize (2) transient versus (3) quasi-steady-state components.


METHODS
Ten normal-hearing young-adult females.


RESULTS
The findings failed to demonstrate statistically significant differences between delay conditions for any of the three speech-token treatments.


CONCLUSIONS
An algorithm putatively diminishing frequency-dependent cochlear delays failed to systematically deteriorate performance in all subjects for the fixed time-frequency transform, stimulus parameters, and test materials employed. Yet, trends were evident such that some effect of perturbing cochlear delays could not be ruled out completely.
* Department of Communication Science and Disorders, University of Pittsburgh , Pennsylvania , USA.
Ethan I
EI
Huang
John D
JD
Durrant
J Robert
JR
Boston
D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D001302:Audiometry, Speech; D003051:Cochlea / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D009622:Noise / Q000009:adverse effects*; D013067:Speech Perception / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
Cochlear delay; digital hearing instruments; speech recognition in noise