Prediction of Motor Recovery Using Initial Impairment and fMRI 48 h Poststroke

There is substantial interpatient variation in recovery from upper limb impairment after stroke in patients with severe initial impairment. Defining recovery as a change in the upper limb Fugl-Meyer score (delta FM), we predicted delta FM with its conditional expectation (i.e., posterior mean) given upper limb Fugl-Meyer initial impairment (FM(ii)) and a putative functional magnetic resonance imaging (fMRI) recovery measure. Patients with first time, ischemic stroke were imaged at 2.5 +/- 2.2 days poststroke with 1.5-T fMRI during a hand closure task alternating with rest (fundamental frequency = 0.025 Hz, scan duration = 172 s). Confirming a previous finding, we observed that the prediction of delta FM by FM(ii) alone is good in patients with nonsevere initial hemiparesis but is not good in patients with severe initial hemiparesis (96% and 16% of the total sum of squares of delta FM explained, respectively). In patients with severe initial hemiparesis, prediction of delta FM by the combination of FM(ii) and the putative fMRI recovery measure nonsignificantly increased predictive explanation from 16% to 47% of the total sum of squares of delta FM explained. The implications of this preliminary negative result are discussed.