Improvement in aphasia scores after stroke is well predicted by initial severity

Abstract

Background and purpose: Most improvement from poststroke aphasia occurs within the first 3 months, but there remains unexplained variability in recovery. Recently, we reported a strong correlation between initial impairment and change scores in motor recovery at 90 days. We wanted to determine whether aphasia recovery (defined as a change from baseline to 90 days) shows a comparably strong correlation and whether the relation was similar to that in motor recovery.

Methods: Twenty-one stroke patients had aphasia scores on the Western Aphasia Battery (WAB) obtained on stroke admission (WAB(initial)) and at 90 days (WAB(3 mo)). The relation between actual change (Delta) scores (defined as WAB(3 mo)- WAB(initial)) and WAB(initial) was calculated in multiple-regression analysis.

Results: Regression analysis demonstrated that WAB(initial) was highly correlated with DeltaWAB (R(2)=0.81, P<0.001) and that, in addition, the relation between WAB(initial) and DeltaWAB was proportional, such that patients recovered 0.73 of maximal potential recovery (WAB(maximum)-WAB(initial)).

Conclusions: We show that, like motor recovery, there is a highly predictable relation between aphasia recovery and initial impairment, which is also proportional in nature. The comparability of recovery from motor and language impairment suggests that common mechanisms may govern reduction of poststroke neurologic impairment across different functional domains and that they could be the focus of therapeutic intervention.

Figure 1

The relationship between the achieved change score on the Western Aphasia Battery (WAB) from baseline to follow-up at 90 days (Achieved ΔWAB) to the maximum possible change score (Potential ΔWAB) for patients receiving therapy, not receiving therapy, and unknown therapy status, respectively. The 95% confidence intervals are displayed above and below. The equation for the curve is y = 1.11x + 1.6834.