Vocabulary influences older and younger listeners' processing of dysarthric speech.
This study examined younger (n = 16) and older (n = 16) listeners' processing of dysarthric speech-a naturally occurring form of signal degradation. It aimed to determine how age, hearing acuity, memory, and vocabulary knowledge interacted in speech recognition and lexical segmentation. Listener transcripts were coded for accuracy and pattern of lexical boundary errors. For younger listeners, transcription accuracy was predicted by receptive vocabulary. For older listeners, this same effect existed but was moderated by pure-tone hearing thresholds. While both groups employed syllabic stress cues to inform lexical segmentation, older listeners were less reliant on this perceptual strategy. The results were interpreted to suggest that individuals with larger receptive vocabularies, with their presumed greater language familiarity, were better able to leverage cue redundancies within the speech signal to form lexical hypothesis-leading to an improved ability to comprehend dysarthric speech. This advantage was minimized as hearing thresholds increased. While the differing levels of reliance on stress cues across the listener groups could not be attributed to specific individual differences, it was hypothesized that some combination of larger vocabularies and reduced hearing thresholds in the older participant group led to them prioritize lexical cues as a segmentation frame.
Department of Communication Disorders and New Zealand Institute of Language, Brain and Behaviour, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
Megan J
MJ
McAuliffe
Elizabeth M R
EM
Gibson
Sarah E
SE
Kerr
Tim
T
Anderson
Patrick J
PJ
LaShell
D000161:Acoustic Stimulation; D000293:Adolescent; D000367:Age Factors; D000368:Aged; D001301:Audiometry, Pure-Tone; D001302:Audiometry, Speech; D001309:Auditory Threshold; D003463:Cues; D004401:Dysarthria / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006309:Hearing; D006801:Humans; D008297:Male; D008875:Middle Aged; D046709:Pattern Recognition, Physiological; D010700:Phonetics; D021641:Recognition, Psychology; D013061:Speech Acoustics; D013067:Speech Perception; D014825:Vocabulary; D014833:Voice Quality; D055815:Young Adult