Can non-linguistic cognitive stimulation enhance the cognitive and linguistic functions of people with aphasia receiving conversation therapy? Preliminary findings

Background: Non-linguistic cognitive deficits, which are common in people with aphasia (PWA), have been found to predict language treatment gains, particularly in naming therapy. Interventions for cognitive impairments and their potential benefits to language functioning have been explored via principles based on cognitive training and rehabilitation with mixed results. However, the effects of cognitive stimulation, which has been widely adopted in people with dementia, have not been explored in PWA. Aims: This preliminary study aimed to investigate the effects of non-linguistic cognitive stimulation on cognitive functions of PWA and/or outcomes of language treatment. It was hypothesized that cognitive stimulation utilizing non-linguistic materials might enhance the cognitive abilities of PWA, and such improvements might augment treatment gains in functional communication of PWA who received conversation therapy concurrently. Methods & Procedures: Forty-seven Cantonese-speaking PWA received either conversation therapy and cognitive stimulation or conversation therapy alone. Language outcomes included the number of main concepts produced by PWA spontaneously during narration based on wordless comic strips and video-taped stories to a communication partner. A procedural description task served as the control task. Cognitive treatment outcomes were defined by two cognitive factors extracted from principal component analysis of a cognitive battery tapping attention, short-term/working memory and EF, identified as simple attention and memory (Factor 1) and executive functions (Factor 2) in a recent study (Wong & Law, 2022). Linear mixed effects (LME) modeling was carried out with cognitive and language outcomes as dependent variables while treatment condition and timepoint as fixed factors. Outcomes & Results: Contrary to expectation, participants in both treatment conditions improved in cognitive and language outcomes to a similar extent immediately post-treatment. Maintenance of treatment gains in both functional communication and EF was present in both groups 8-week post treatment but not in tasks reflecting simple attention and memory. No change was observed in the language control task. Conclusions: Based on the preliminary findings, improvements in cognitive and linguistic performances are attributed to the meta-cognitive, explicit, goal-directed, interactive and naturalistic nature of conversation therapy. Meanwhile, the null effect of cognitive stimulation might be related to the differences in the training materials used, as well as the neuropathology of people with stroke versus people with dementia, and hence their differential responsiveness to the cognitive intervention.