RESUMEN
BACKGROUND: The principles of motor learning (PML) emerged from studies of limb motor skills in healthy, young adults. The applicability of these principles to speech motor learning, and to older adults, is uncertain. AIMS: The purpose of this study was to examine one PML, feedback frequency, and its effect on retention and generalization of a novel speech and comparable tracing task. METHODS: Sixty older adults completed a speech motor learning task requiring the production of a novel phrase at speaking rates 2 times and 3 times slower than habitual rate. Participants also completed a limb motor learning task requiring the tracing of a sine wave 2x and 3x slower than habitual rate. Participants were randomly assigned to receive feedback every trial, every 5th trial, or every 10th trial. Mean absolute error was measured to examine immediate generalization, delayed generalization, and 2-day retention. FINDINGS: Results suggested that feedback frequency did not have an effect on the retention and generalization of the speech or manual task, supporting the small but growing literature highlighting the constraints of generalizing the PML to other modalities and populations.
RESUMEN
PURPOSE: The purpose of this study was to examine the effects of an internally versus externally cued speech task on perceived understandability and naturalness in speakers with Parkinson's disease (PD) and cerebellar disease (CD). METHOD: Sentences extracted from a covertly recorded conversation (internally cued) were compared to the same sentences read aloud (externally cued) by speakers with PD and a clinical comparison group of speakers with CD. Experienced listeners rated the speech samples using a visual analog scale for the perceptual dimensions of understandability and naturalness. RESULTS: Results suggest that experienced listeners rated the speech of participants with PD as significantly more natural and more understandable during the reading condition. Participants with CD were also rated as significantly more understandable during the reading condition, but ratings of naturalness did not differ between conversation and reading. CONCLUSIONS: Speech tasks can have a pronounced impact on perceived speech patterns. For individuals with PD, both understandability and naturalness can improve during reading tasks versus conversational tasks. The speech benefits from reading may be attributed to several mechanisms, including possible improvement from an externally cued speech task. These findings have implications for speech task selection in evaluating individuals with dysarthria.