Familiarisation conditions and the mechanisms that underlie improved recognition of dysarthric speech

Abstract

This investigation evaluated the familiarisation conditions required to promote subsequent and more long-term improvements in perceptual processing of dysarthric speech and examined the cognitive-perceptual processes that may underlie the experience-evoked learning response. Sixty listeners were randomly allocated to one of three experimental groups and were familiarised under the following conditions: (1) neurologically intact speech (control), (2) dysarthric speech (passive familiarisation), and (3) dysarthric speech coupled with written information (explicit familiarisation). All listeners completed an identical phrase transcription task immediately following familiarisation, and listeners familiarised with dysarthric speech also completed a follow-up phrase transcription task 7 days later. Listener transcripts were analysed for a measure of intelligibility (percent words correct), as well as error patterns at a segmental (percent syllable resemblance) and suprasegmental (lexical boundary errors) level of perceptual processing. The study found that intelligibility scores for listeners familiarised with dysarthric speech were significantly greater than those of the control group, with the greatest and most robust gains afforded by the explicit familiarisation condition. Relative perceptual gains in detecting phonetic and prosodic aspects of the signal varied dependent upon the familiarisation conditions, suggesting that passive familiarisation may recruit a different learning mechanism to that of a more explicit familiarisation experience involving supplementary written information. It appears that decisions regarding resource allocation during subsequent processing of dysarthric speech may be informed by the information afforded by the conditions of familiarisation.

Cognitive–Perceptual Examination of Remediation Approaches to Hypokinetic Dysarthria

“…Using this methodological approach, a number of studies have shown that, when faced with dysarthric speech, listeners exploit syllabic stress cues as they attempt to identify word boundaries (Borrie et al, 2012;Choe, Liss, Azuma, & Mathy, 2012;Liss, Spitzer, Caviness, Adler, & Edwards, 1998;Liss, Spitzer, Caviness, Adler, & Edwards, 2000). What is not known is whether the behavioral speech strategies commonly used assist listeners in their attempts to identify word boundaries.…”

“…Borrie et al demonstrated that when a listener was familiarized with dysarthric speech, erroneously transcribed syllables were more phonemically like the intended target than when listeners had not received familiarization. The results were interpreted to suggest that familiarization with dysarthric speech "enabled listeners to better map acoustic-phonetic aspects of the disordered signal onto existing mental representations of speech sounds" (Borrie et al, 2012(Borrie et al, , p. 1052.…”

“…Through examination of transcription error patterns, evidence of listeners' cognitiveperceptual processing strategies can be observed. To date, studies that have used a cognitive-perceptual processing approach to dysarthric speech have characterized speech spoken in habitual conditions (Choe et al, 2012;Liss et al, 1998Liss et al, , 2000 or have investigated the effects of familiarization (i.e., listener training) on perception (Borrie et al, 2012;Liss, Spitzer, Caviness, & Adler, 2002;Spitzer et al, 2000). To the best of our knowledge, researchers have yet to take this one step further and pit remediation techniques against each other to directly examine how listeners' processing of dysarthric speech is enhanced, or otherwise, by common behavioral speech interventions.…”

“…Spitzer, Liss, Caviness, and Adler (2000) showed that the transcription errors of listeners who were exposed to dysarthric speech prior to completing a transcription task exhibited greater phonemic resemblance to the target compared with those who did not complete a familiarization procedure. Borrie et al (2012) subsequently developed a measure called syllable resemblance, which quantified the degree of phonemic relatedness of an erroneous transcription to the target. Borrie et al demonstrated that when a listener was familiarized with dysarthric speech, erroneously transcribed syllables were more phonemically like the intended target than when listeners had not received familiarization.…”

The role of linguistic and indexical information in improved recognition of dysarthric speech

“…An independent t-test between percent correct identification for listeners who received the word identification training task (M ¼ 77.36, SD ¼ 4.2) and listeners who Immediately following the training task phase, the training groups and the control group participated in an identical test phase, in which they transcribed the 36 novel phrases that made up the test speech set. Transcription task instructions were identical to those of the previous two studies (Borrie et al, 2012b;Borrie et al, 2012c). Phrases were presented one at a time and listeners were asked to listen carefully to each phrase and to type exactly what they heard.…”