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 (WABinitial) and at 90 days (WAB3 mo). The relation between actual change (Δ) scores (defined as WAB3 mo-WABinitial) and WABinitial was calculated in multiple-regression analysis. Results: Regression analysis demonstrated that WABinitial was highly correlated with ΔWAB (R=0.81, P<0.001) and that, in addition, the relation between WABinitial and ΔWAB was proportional, such that patients recovered 0.73 of maximal potential recovery (WABmaximum-WABinitial). 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. Copyright © 2010 American Heart Association. All rights reserved.