Relationship Between Cognitive Function and Dysphagia After Stroke

OBJECTIVE To investigate the characteristics of cognitive deficits in patients with post-stroke dysphagia, and to analyze the relationships between cognitive dysfunction and severity of dysphagia in supratentorial stroke. METHODS A total of 55 patients with first-ever supratentorial lesion stroke were enrolled retrospectively, within 3 months of onset. We rated dysphagia from 0 (normal) to 4 (severe) using the dysphagia severity scale (DSS) through clinical examinations and videofluoroscopic swallowing studies (VFSS). The subjects were classified either as non-dysphagic (scale 0) or dysphagic (scale 1 to 4). We compared general characteristics, stroke severity and the functional scores of the two groups. We then performed comprehensive cognitive function tests and investigated the differences in cognitive performance between the two groups, and analyzed the correlation between cognitive test scores, DSS, and parameters of oral and pharyngeal phase. RESULTS Fugl-Meyer motor assessment, the Berg Balance Scale, and the Korean version of the Modified Barthel Index showed significant differences between the two groups. Cognitive test scores for the dysphagia group were significantly lower than the non-dysphagia group. Significant correlations were shown between dysphagia severity and certain cognitive subtest scores: visual span backward (p=0.039), trail making tests A (p=0.042) and B (p=0.002), and Raven progressive matrices (p=0.002). The presence of dysphagia was also significantly correlated with cognitive subtests, in particular for visual attention and executive attention (odds ratio [OR]=1.009; 95% confidence interval [CI], 1.002-1.016; p=0.017). Parameters of premature loss were also significantly correlated with the same subtests (OR=1.009; 95% CI, 1.002-1.016; p=0.017). CONCLUSION Our results suggest that cognitive function is associated with the presence and severity of post-stroke dysphagia. Above all, visual attention and executive functions may have meaningful influence on the oral phase of swallowing in stroke patients with supratentorial lesions.