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

Abstract

Objectives: The outcome of aphasia at 3 months 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.

Methods: 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.

Results: ART at D7, infarct volume, and the intersection index were univariate predictors of good outcome. In the multivariate analysis, ART D7 and "volume ≥ 50 ml 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.

Conclusion: In patients with initially severe aphasia, large infarct size or critical damage in left temporoparietal junction is associated with poor language outcome at 3 months.

Keywords: Aphasia; Magnetic resonance imaging; Prognosis.