A Clinical Advantage: Experience Informs Recognition and Adaptation to a Novel Talker With Dysarthria

Abstract

Purpose Perceptual training paradigms, which leverage the mechanism of perceptual learning, show that naïve listeners, those with no prior experience with dysarthria, benefit from explicit familiarization with a talker with dysarthria. It is theorized that familiarization affords listeners an opportunity to acquire distributional knowledge of the degraded speech signal. Here, we extend investigations to clinically experienced listeners, speech-language pathologists (SLPs), and advance models of listener recognition and adaptation to dysarthric speech. Method Forty-seven SLPs completed a standard three-phase perceptual training protocol (pretest, familiarization, and posttest) with a novel talker with dysarthria. Intelligibility scores were compared with historical data from naïve listeners. Potential relationships between intelligibility scores and characteristics of clinical experience were examined. Results Intelligibility scores of SLPs improved by an average of 19% from pretest to posttest. This intelligibility improvement was lower than naïve listeners, although the difference was small. Moreover, clinical characteristics related to level of dysarthria experience (e.g., percent of caseload composed of dysarthria) predicted pretest/initial intelligibility. No predictive relationships between clinical characteristics and intelligibility improvement were revealed. Conclusions As a group, SLPs benefitted from perceptual training, suggesting that, despite prior experience, the opportunity to acquire knowledge of talker-specific cue distributions is crucial for optimal adaptation. However, SLPs with greater dysarthria experience were better at initially understanding the talker with dysarthria. This suggests that, through regular interaction with individuals with dysarthria, clinicians acquire knowledge of the cue distributions of dysarthric speech more generally and can generalize this group-specific knowledge to aid in understanding other talkers with dysarthria. Consistent with theoretical models of perceptual learning, both talker- and group-specific knowledge informed recognition and adaptation to dysarthric speech.

Figures

Figure 1.

Intelligibility scores, indexed by percent words correct, for pretest and posttest, with box plots showing distributional spread. The first panel reports data from the experienced listeners in the current study. The second and third panels report historical data from naïve listeners and control listeners, respectively (Borrie et al., 2017a).

Figure 2.

Experienced listeners plotted according to clinical characteristics: current setting, percent caseload, and perceived competence. This shows the proportions of individuals in each setting that are in each percent caseload category and how these proportions are further related to perceived competence, illustrating significant relationships between these three characteristics. University, medical, and school + early intervention (EI) are represented by yellow, green, and purple, respectively.

Figure 3.

Average intelligibility scores, indexed by percent words correct, for both pretest and posttest, for experienced listeners by (a) current setting, (b) percent caseload, and (c) perceived competence. All three panels show that initial intelligibility differs as a function of the clinical characteristic, whereas intelligibility improvement does not. For visual reference, historical data from naïve listeners are included in all three panels (Borrie et al., 2017a).