Frequency of domain-specific cognitive impairment in sub-acute and chronic stroke

Functional contributions of cognitive impairment may vary by domain and severity.

(1) To characterize frequency of cognitive impairment by domain after stroke by severity (mild: -1.5 ≤ z-score < -2; severe: Z ≤ -2) and time (sub-acute: < 90d; chronic: 90d-2yrs); and (2) To assess the association of cognitive impairment with function in chronic stroke.

Cognitive function was characterized among 215 people with sub-acute or chronic stroke (66.8 years, 43.3% female). Z-scores by cognitive domain were determined from normative data. Function was defined as the number of IADLs minimally independent.

76.3% of sub-acute and 67.3% of chronic stroke participants had cognitive impairment in ≥ 1 domain (p-for-difference = 0.09). Severe impairment was most common in psychomotor speed (sub-acute: 53.5%; chronic: 33.7%). Impairment in executive function was common (sub-acute: 39.5%; chronic: 30.7%) but was usually mild. Severe impairment in psychomotor speed, visuospatial function, and language and any impairment in executive function and memory was associated with IADL impairment (p < 0.03).

Mild cognitive impairment is common after stroke but is not associated with functional disability. Impairment in psychomotor speed, executive function, and visuospatial function is common and associated with functional impairment so should be a focus of screening and rehabilitation post-stroke.