A Comparison of Outcome Measures for Speech Motor Learning in Acquired Apraxia of Speech Using Motor Learning Guided Treatment

Abstract

Acquired apraxia of speech (AOS) in isolation following a stroke is a rare occurrence; it is often accompanied by aphasia and/or dysarthria. Distinguishing characteristics of AOS are sound substitutions and sound distortions, an increase in these distortions with an increased rate and/or increased complexity, articulatory inaccuracy related to place and manner, and a disproportionate number of words per minute relative to maximum sustained vowel duration [1,2]. Most AOS treatment protocols are characterized as articulatory-kinematic approaches based on the theoretical framework that AOS is a phonatory-motor disorder. This distinction is relevant given the diversity of outcome measures reported across treatment studies. Outcome measures reported in the literature vary from binary systems to multidimensional rating scales. Each system comes with its own advantage and disadvantage Purpose: The purpose of this study was to investigate potential benefits of using a qualitative and quantitative outcome measure of articulation accuracy and suprasegmental characteristics in isolation for speech motor learning in acquired apraxia of speech (AOS). Methods: Baseline, retention, and maintenance measures from an oral reading task of 2 speakers with chronic AOS and aphasia were rated using an 11-point multidimensional rating scale accounting for articulation and immediacy and a hybrid scale measuring number of correctly produced words, presence of distortions in correctly produced words, and immediacy of the production. Participants received motor learning guided treatment two days a week for eighteen sessions. Results: The multidimensional rating scale and the hybrid scale comparably represented speech motor changes related to articulation accuracy and immediacy of the production across the duration of the intervention. The hybrid scale provided a sensitive measure for individual differences in immediacy and presence of distortions not represented in the multidimensional rating scale. Conclusions: The results of this pilot study provide evidence to support the benefit of using a qualitative and quantitative outcome measure for speech motor changes in acquired AOS. The individual differences identified through the hybrid scale have clinical and research implications.

Statistical Analysis of fNIRS Data: Consideration of Spatial Varying Coefficient Model of Prefrontal Cortex Activity Changes During Speech Motor Learning in Apraxia of Speech

“…This pattern of activity is consistent with previous reports of left hemisphere dominance with speaking tasks [18,19] and the dual-processing theory [22]. The speech behavior during retention measures for P1 characterized speech productions as consistent decrease occurrences of segmental and intersegmental durations with fewer long durations compared to baseline [27]. However, for P2, the PFC activity remained bilateral, indicating the involvement of cognitive control processes throughout the intervention period.…”

“…Multiple single-case treatment studies report positive outcomes [26][27][28][29]. A recent single-case treatment study involving two individuals with chronic AOS and aphasia, report positive treatment effects on treated items while comparing two methods to measure speech motor learning [27]. This study highlights the challenges clinicians face to measure changes in speech production in the presence of aphasia.…”

“…They both had an overall slow rate of speech with longer segmental and intersegmental durations and equal stress across syllables. Please see Johnson et al [27] for a complete description of participants, stimuli, and behavioral outcome measures. Prior to participation in this study, written informed consent according to IRB approval was obtained.…”

“…Stage 1 elicits productions using a written prompt and clinician verbal model, while Stage 2 and Stage 3 elicit productions using a written prompt only. The delay imposed between productions in Stage 1 and Stage 2 is 4 s, while in Stage 3, it is 10 s. The 18 days of intervention trained stimuli according to behavior outcomes; P1 practiced set 1 for days 1-12 and set 2 for days 13-18, whereas P2 practiced the same set for the 18 days [27].…”

“…The rating of these productions using a Likert scale is the behavior indicator for speech motor learning. Multiple single-case treatment studies report positive outcomes [26][27][28][29]. A recent single-case treatment study involving two individuals with chronic AOS and aphasia, report positive treatment effects on treated items while comparing two methods to measure speech motor learning [27].…”