Age-Related Changes in Temporal Resolution Revisited: Electrophysiological and Behavioral Findings From Cochlear Implant Users.
Bruna S S Mussoi, Carolyn J Brown
PMID 31033701WHAT IT FOUND
Older and younger cochlear implant users detected brief gaps almost equally well.
Only recovery from a high-rate pulse train differed by age. Working memory, not gap detection, was linked to hearing speech in noise.
Key findings
01Behavioral gap detection was similar in younger and older CI users, with median thresholds of 2.8 ms and 2.91 ms.
02Recovery after a high-rate pulse train masker was faster in younger CI users, while recovery after a single-pulse masker was not different between groups.
03Digit span was the only temporal-resolution or cognitive measure associated with speech perception in noise: listeners who repeated more digits had lower SNR loss.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Only 20 CI users were tested, with 10 in each age group, so the study had limited power to detect age effects. The study compared two age groups at testing, so it cannot show that aging caused the differences. One younger participant could not contribute the pulse-train recovery measure because responses were too small. The cortical responses were noisy, and the study did not include a no-change condition that could have helped interpretation. The temporal-resolution stimuli may have been too simple to reveal age effects or to relate to everyday speech perception. The participants had relatively short duration of profound deafness (median 3 years, mean 4.85 years), so results may not apply to CI users with long-standing deafness. The older participants passed a cognitive screen and were more educated than the general older US population, so they may not represent older CI users with cognitive decline or less education. The only positive temporal finding was one measure and did not agree with the other temporal measures in the same participants.
Declared interests
The authors declared no conflicts of interest. The article metadata lists NIH extramural and non-U.S. government research support.
The easy way to misread this
Do not assume that a cochlear implant user's difficulty hearing in noise is caused by reduced temporal resolution. In this study, gap detection thresholds were similar across age groups, and only digit span was associated with speech-in-noise scores; the study included only 20 CI users and did not test whether working memory caused better speech perception.