Speech Fluency in Acquired Apraxia of Speech During Narrative Discourse: Group Comparisons and Dual-Task Effects

Abstract

Purpose Slowed speech and interruptions to the flow of connected speech are common in aphasia. These features are also observed during dual-task performance for neurotypical adults. The purposes of this study were to determine (a) whether indices of fluency related to cognitive–linguistic versus motor processing would differ between speakers with aphasia plus apraxia of speech (AOS) and speakers with aphasia only and (b) whether cognitive load reduces fluency in speakers with aphasia with and without AOS. Method Fourteen speakers with aphasia (7 with AOS) and 7 neurotypical controls retold short stories alone (single task) and while simultaneously distinguishing between a high and a low tone (dual task). Their narrative samples were analyzed for speech fluency according to sample duration, speech rate, pause/fill time, and repetitions per syllable. Results As expected, both speaker groups with aphasia spoke slower and with more pauses than the neurotypical controls. The speakers with AOS produced more repetitions and longer samples than controls, but they did not differ on these measures from the speakers with aphasia without AOS. Relative to the single-task condition, the dual-task condition increased the duration of pauses and fillers for all groups but reduced speaking rate only for the control group. Sample duration and frequency of repetitions did not change in response to cognitive load. Conclusions Speech output in aphasia becomes less fluent when speakers have to engage in simultaneous tasks, as is typical in everyday conversation. Although AOS may lead to more sound and syllable repetitions than normal, speaking tasks other than narrative discourse might better capture this specific type of disfluency. Future research is needed to confirm and expand these preliminary findings. Supplemental Material https://doi.org/10.23641/asha.8847845

Repeated attempts, phonetic errors, and syllabifications in a case study:Evidence of impaired transfer from phonology to articulatory planning

“…RAs, however, could also arise at a later stage in motor planning/ programming where an incorrect motor plan is revised. Consistent with this second locus, they have also been observed in AoS (Darley, 1968;Harmon et al, 2019;Trost, 1970).…”

“…In contrast, CS 1 would have a deficit in the initiation map as part of motor planning. Both speakers, however, have intact auditory feedback and forward models, given that they can monitor and correct errors (see also Harmon et al, 2019;Jacks & Haley, 2015;Maas et al, 2015 for the importance of internal mechanisms of control in AoS). To give another example, Tilsen (2013) has argued that articulatory programming occurs through the interplay of two mechanisms: a "selection control" mechanism, for choosing which movement to produce, and a "coordination" mechanism, for precision control over the timing of movement execution.…”

“…Other studies showed a relatively low percentage of successful outcomes in speakers with CA (36% and 30%, respectively, in Gandour et al, 1994;Kohn, 1989). Still other studies showed a similar incidence of RAs across clinical classifications (Harmon et al, 2019;Marshall & Tompkins, 1982). It is unclear, therefore, whether RAs have different characteristics in speakers with AoS and CA.…”

“…First, we want to better document the characteristics of RAs in a PWA with associated evidence of articulatory difficulties. Studies describing RA are very limited, both in the context of AoS (see Darley, 1968;Harmon et al, 2019;Trost, 1970) and in the context of CA (e.g., Christman et al, 2004;Franklin et al, 2002;Joanette et al, 1980;Kohn, 1984Kohn, , 1989Marshall & Tompkins, 1982). For RAs we mean both false starts, where a fragment of the word is produced followed by a more complete response, and response revisions/self-corrections, where a complete but erroneous response is produced followed by spontaneous new attempts at the target (similarly to a conduite d'approche).…”