A comparison of verbal and gesture treatments for a word production deficit resulting from acquired apraxia of speech

Background: Acquired apraxia of a speech (AOS) is a commonly encountered word production deficit following stroke. The efficacy of treatments for AOS is the subject of several recent studies. Evidence is mounting that verbal‐based treatment methods result in improved production of treated phonemes in trained contexts (Schneider & Frens, 2005; Wambaugh et al., 1998; Wambaugh & Martinez, 2000; Wambaugh et al., 1999; Wambaugh & Nessler, 2004). Alternatively, arm and hand gestures have previously been suggested as a possible useful treatment method/modality for AOS (Rao, 2001; Skelly et al., 1974; Wertz et al., 1984), and multi‐modality treatments are often considered more efficacious than single‐modality treatments, but there is minimal empirical evidence to support these suggestions. Speech‐language pathologists have little evidence on which to base their choice of gesture or verbal treatment methods. Such evidence is vital for ensuring treatment efficiency in clinical environments where total treatment times are reducing. We gratefully acknowledge the generous and patient participation of AS in this research. Thank you to Lisa Bryne and Donna McNeil‐Brown for inter‐rater agreement work, and Professor Tom Matyas, La Trobe University, for expert statistical guidance. This research was partly carried out while the first author was the recipient of an Australian Government Post Graduate Award, and further supported by a La Trobe University Faculty of Health Sciences Research Grant. Aims: This study aimed to investigate the relative efficacy of gesture, verbal, and combined verbal plus gesture treatments for a patient with chronic moderate acquired apraxia of speech. Methods & Procedures: AS, a 52‐year‐old male, participated in the study. AS sustained a single left fronto‐temporal stroke 60 months prior to the study, which resulted in Broca's aphasia and a moderate apraxia of speech. AS participated in a controlled multiple‐baseline single‐case experiment comparing the efficacy of the three treatments for the production of multi‐syllable words and words containing double and triple consonant clusters. Outcomes & Results: Large, statistically significant, and clinically relevant treatment effects were found for all three treatment conditions and there were no significant differences between conditions. Improvements made in word production were maintained at both the 1‐month and 3‐month follow‐up assessments. Generalisation of enhanced word production was found for trained sounds and clusters to untreated words and to conversation. Conclusions: The results caution clinicians to question the superiority of multi‐modal treatments for acquired apraxia of speech. Consistent with our previous work (Rose & Douglas, 2001, in press; Rose et al., 2002), it is suggested that the underlying treatment strategy—in this case, knowledge about phoneme place and manner of production—is a more potent factor in treatment outcome than the modality (gesture versus verbal) in which the strategy is presented. The suggestions recently made in the AOS literature to incorporate multiple sound targets in a session, blocked versus random order of practice, and complex stimuli all gained support from results of the current study.