An exploration of familiarization effects in the perception of hypokinetic and ataxic dysarthric speech

This study explored a methodology for analyzing and quantifying listeners' transcriptions of ataxic and hypokinetic dysarthric speech to assess the effects of a familiarization procedure on listeners' perceptions. The transcripts of 34 listeners were analyzed for the presence of word substitution errors. Errors were classified as phonemically resembling the target words in either their vowel or consonant structure, or as bearing no phonemic resemblance to the targets. While the familiarization procedure resulted in higher intelligibility scores for listeners transcribing both the hypokinetic and ataxic speech signals, the potential phonemic benefits of familiarization were only observed for the listeners who transcribed the ataxic speech. This benefit was evidenced by a higher portion of the target consonants present in word substitutions and a lower number of substitution errors that were not phonemically related to the intended targets. The absence of significant findings in the hypokinetic transcripts may be an artifact of this level of analysis. A more fine-grained level of analysis may be required to effectively capture the perceptual benefits of the familiarization procedure on listeners transcribing the hypokinetic speech signal.