Speech perception in older hearing impaired listeners: benefits of perceptual training.
Hearing aids (HAs) only partially restore the ability of older hearing impaired (OHI) listeners to understand speech in noise, due in large part to persistent deficits in consonant identification. Here, we investigated whether adaptive perceptual training would improve consonant-identification in noise in sixteen aided OHI listeners who underwent 40 hours of computer-based training in their homes. Listeners identified 20 onset and 20 coda consonants in 9,600 consonant-vowel-consonant (CVC) syllables containing different vowels (/ɑ/, /i/, or /u/) and spoken by four different talkers. Consonants were presented at three consonant-specific signal-to-noise ratios (SNRs) spanning a 12 dB range. Noise levels were adjusted over training sessions based on d' measures. Listeners were tested before and after training to measure (1) changes in consonant-identification thresholds using syllables spoken by familiar and unfamiliar talkers, and (2) sentence reception thresholds (SeRTs) using two different sentence tests. Consonant-identification thresholds improved gradually during training. Laboratory tests of d' thresholds showed an average improvement of 9.1 dB, with 94% of listeners showing statistically significant training benefit. Training normalized consonant confusions and improved the thresholds of some consonants into the normal range. Benefits were equivalent for onset and coda consonants, syllables containing different vowels, and syllables presented at different SNRs. Greater training benefits were found for hard-to-identify consonants and for consonants spoken by familiar than unfamiliar talkers. SeRTs, tested with simple sentences, showed less elevation than consonant-identification thresholds prior to training and failed to show significant training benefit, although SeRT improvements did correlate with improvements in consonant thresholds. We argue that the lack of SeRT improvement reflects the dominant role of top-down semantic processing in processing simple sentences and that greater transfer of benefit would be evident in the comprehension of more unpredictable speech material.
Human Cognitive Neurophysiology Laboratory, VANCHCS, 150 Muir Rd., Martinez, CA, 95553, United States of America; UC Davis Department of Neurology, 4860 Y St., Suite 3700, Sacramento, CA, 95817, United States of America; Center for Neurosciences, UC Davis, 1544 Newton Ct., Davis, CA, 95616, United States of America; UC Davis Center for Mind and Brain, 202 Cousteau Place, Suite 201, Davis, CA, 95616, United States of America.
David L
DL
Woods
Human Cognitive Neurophysiology Laboratory, VANCHCS, 150 Muir Rd., Martinez, CA, 95553, United States of America.
Zoe
Z
Doss
Human Cognitive Neurophysiology Laboratory, VANCHCS, 150 Muir Rd., Martinez, CA, 95553, United States of America.
Timothy J
TJ
Herron
Human Cognitive Neurophysiology Laboratory, VANCHCS, 150 Muir Rd., Martinez, CA, 95553, United States of America.
Tanya
T
Arbogast
Human Cognitive Neurophysiology Laboratory, VANCHCS, 150 Muir Rd., Martinez, CA, 95553, United States of America.
Masood
M
Younus
Human Cognitive Neurophysiology Laboratory, VANCHCS, 150 Muir Rd., Martinez, CA, 95553, United States of America.
Marc
M
Ettlinger
Human Cognitive Neurophysiology Laboratory, VANCHCS, 150 Muir Rd., Martinez, CA, 95553, United States of America.
E William
EW
Yund
D000368:Aged; D000369:Aged, 80 and over; D001309:Auditory Threshold / Q000502:physiology; D012048:Correction of Hearing Impairment; D006310:Hearing Aids; D034381:Hearing Loss / Q000503:physiopathology* / Q000534:rehabilitation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010353:Patient Education as Topic; D010470:Perceptual Masking / Q000502:physiology; D059629:Signal-To-Noise Ratio; D013067:Speech Perception / Q000502:physiology*; D013069:Speech Reception Threshold Test