Non-Verbal Working Memory in Post-Stroke Motor Aphasia: A Pilot Study Using the Tactual Span

Background: Working memory (WM) impairment is a potential consequence of motor aphasia resulting from left-hemisphere ischemic stroke. While verbal WM has been studied extensively in this disorder, research regarding non-verbal modalities remains limited, particularly visuospatial WM, tactile WM, and the relationship between them. Additionally, language impairments limit the ability to assess WM in aphasia patients, highlighting the necessity of non-verbal diagnostic tools in clinical practice. The current study's objectives were to compare tactile and visuospatial WM in patients with post-stroke motor aphasia and to validate the one-hand version of the Tactual Span task as a clinical measure of WM. Methods: A total of 29 participants-14 with post-stroke motor aphasia and 15 healthy controls-completed a battery of cognitive tests, including the Raven's Colored Progressive Matrices Test, the Visuospatial Span, the Tactual Span, and a visual 1-Back task. Results: There was significantly lower performance across all WM tasks in the aphasia group compared to the controls. Additionally, the Tactual Span successfully discriminated between patients and controls, showing sensitivity estimates of 92.9% and a specificity of 66.7%, with a cut-off score of 4.5 (AUC = 0.91), for the forward stage. The backward stage revealed a sensitivity of 71.4% and a specificity of 73.3%, with a cut-off score of 3.5 (AUC = 0.83). Conclusions: The findings may suggest that non-verbal WM impairment in post-stroke aphasia affects both visuospatial and tactile modalities similarly. Furthermore, the Tactual Span appears to be sensitive to left-hemisphere stroke damage, suggesting its potential utility as a clinical tool for WM assessment in patients with motor aphasia.