Aphasia outcome: the interactions between initial severity, lesion size and location.

Abstract

The outcome of aphasia at 3months is variable in patients with moderate/severe stroke. The aim was to predict 3-month aphasia outcome using prediction models including initial severity in addition to the interaction between lesion size and location at the acute phase. Patients with post-stroke aphasia (assessed by the Aphasia Rapid Test at day 7-ART D7) and MRI performed at day 1 were enrolled (n = 73). Good outcome at 3-months was defined by an Aphasia Handicap Score of 0-2. Each infarct lesion was overlapped with an area of interest in the left temporo-parietal region to compute an intersection index (proportion of the critical region damaged by the infarct). We tested ART D7, age, lesion volume, and intersection index as well as a combined variable lesion volume*intersection in a univariate analysis. Then, we performed a multivariate analysis to investigate which variables were independent predictors of good outcome. ART at D7, infarct volume, and the intersection index were univariate predictors of good outcome. In the multivariate analysis, ART D7 and "volume ≥ 50ml or intersection index ≥ 20%" correctly classified 89% of the patients (p < 0.0001). When added to the model, the interaction between both variables was significant indicating that the impact of the size or site variable depends on the initial severity of aphasia. In patients with initially severe aphasia, large infarct size or critical damage in left temporoparietal junction is associated with poor language outcome at 3months.