Association of laterality and size of perfusion lesions on neurological deficit in acute supratentorial stroke

Background: The influence of lesion size and laterality on each component of the National Institutes of Health Stroke Scale has not been delineated. The objective of this study was to use perfusion-weighted imaging to characterize the association of ischaemic volume and laterality on each component item and the total score of the <National Institutes of Health Stroke Scale.

Methods: We analysed consecutive right-handed patients with first-ever supratentorial acute ischaemic strokes who underwent acute perfusion-weighted imaging at a single centre. Perfusion deficits were defined as mean transit time > 10 s. Ordinal regression was used to clarify the relationship between ischaemic volume, laterality, and <National Institutes of Health Stroke Scale scores.

Results: Among 111 patients, 58 were left-hemisphere stroke, and 53 right-hemisphere stroke. Median ischaemic volume was 53 ml in left-hand stroke and 65 ml in right-hand stroke and median total National Institutes of Health Stroke Scale was 10 in left-hand stroke and eight in right-hand stroke. For individual National Institutes of Health Stroke Scale items, ischaemic volume correlated most closely with commands and visual field and most weakly with ataxia and neglect. Left-hand stroke predicted higher scores of total National Institutes of Health Stroke Scale and National Institutes of Health Stroke Scale items of questions, commands, right limb weakness, and language. Right-hand stroke predicted higher scores of left limb weakness and extinction.

Conclusions: Larger perfusion defects contribute to higher scores on the total and most individual items of the National Institutes of Health Stroke Scale. However, lesion laterality contributes substantially to half the item scores, with greater association of left than right-brain side. These findings indicate that imaging-deficit correlations will be improved by designating lesions into an atlas, taking into account side in addition to size.