The effects of rate control treatment on consonant production accuracy in mild apraxia of speech

Abstract

Background: A primary feature of acquired apraxia of speech (AOS) is a slow speech rate associated with lengthened sound segments and intersegment durations (McNeil, Robin, & Schmidt, 1997). This disturbance in speech production timing has been the focus of a limited number of treatment studies designed to manipulate rate and/or rhythm of speech production with speakers with mild AOS. Aims: The purpose of this investigation was to study the effects of rate control treatment on sound production accuracy and utterance durations of multisyllabic words, phrases, and sentences in a speaker with mild AOS and aphasia. Methods & Procedures: An individual with mild AOS and aphasia was trained to produce multisyllabic words and phrases using a combination of metronomic rate control and hand tapping. The speaker was trained to produce one syllable per beat of the metronome in conjunction with hand tapping. Feedback was only provided for accuracy of hand tapping and/or syllable production to the beat of the metronome. No feedback was given regarding the accuracy of sound production. Initially, the speaker's rate of production was reduced, but was then systematically increased. A multiple baseline design was used to examine the acquisition, response generalisation, and maintenance effects of treatment. Outcomes & Results: Findings revealed an increase in sound production accuracy for trained four‐syllable words and some improvement in sound production accuracy for treated phrases and untrained four‐syllable words. There was only a slight reduction in total utterance duration for treated items versus untreated items. There was a gradual decline in total utterance duration over time on untrained stimulus generalisation items with no consistent improvement on sound production accuracy. Conclusions: Treatment resulted in an improvement in sound production accuracy in an individual with AOS and aphasia. Positive changes were observed for treated four‐syllable words, phrases, and untrained four‐syllable words, although treatment did not directly target sound production accuracy (i.e., feedback was not given regarding accuracy of productions). The study represents an initial investigation of the effects of rate control treatment specifically increasing rate of production in a speaker with mild AOS and aphasia. This type of treatment appears to have promise in terms of improving sound production accuracy and warrants further investigation.