Motor function recovery after stroke has previously been well described as a recovery of 70% of the initial impairment when the initial impairment was mild to moderate. Two previous studies have found a similar recovery of 70% for aphasia, but these studies examined overall aphasia severity rather than specific language abilities. Since specific language abilities are dissociable after stroke, the current study examines proportional recovery in individual language scores.

Initial severity predicted the recovery for 6 of the 9 subscores analyzed, and explained 35-76% of the variance. In four of the subscores, lesion size also predicted recovery. The proportional recovery ranged from 0.08 to 0.73.

The proportional relationship between initial impairment and recovery was not constant across subscores. For tests of language comprehension, initial severity alone predicts the recovery score, and the proportional recovery rate was closer to the previously described 70%, whereas for measures of language production, initial severity in combination with lesion size predicts the recovery score with a lower proportional recovery rate. Larger sample sizes will be needed to determine the clinical applicability of these findings for aphasia prognosis.