Abstract 2220: Fast Versus Slow Recoverers Following Acute Ischemic Stroke

Abstract

INTRODUCTION: Prior work has identified that the majority of acute hemiparetic patients recover a very predictable (adjusted R2=0.85) 70% of their maximum potential recovery on the Fugl-Meyer Upper Extremity Motor exam (FM) at 3-months. We examined these data to investigate whether the early recovery trajectory was uniform among these patients at 3 months. Among first-time acute stroke patients who recover motor function at 3 months, we assessed the hypothesis that the rate of recovery will be variable at one week after stroke. METHODS: We examined 30 patients with first-ever unilateral hemiparetic stroke using the FM score (max score=66) at 24-72 hours (FMinit), 1 week (FM1wk), and 3-months (FM3mo). Initial impairment was defined as 66 - FMinit. Recovery was defined as the change in FM over 3 months (FM3mo - FMinit). A Pearson correlation coefficient was calculated for predicted vs. observed change to assess how well (0.70 x initial impairment) predicted 3-month recovery, as well as to identify the subgroup of non-recoverers. A histogram was plotted for the recoverers to examine the distribution of patients based on the proportion of the 3-month recovery that had been achieved by 1-week. RESULTS: A strong correlation (R2=0.96) was demonstrated of predicted vs. observed recoveries, with non-recoverers (n=4) removed. Among recoverers, there was a bimodal distribution of patients by the proportion of 3-month recovery achieved at 1-week-- those who achieved >50% of 3-month recovery (fast to recover-- FTR, N=14) vs. those who achieved <50% of 3-month recovery (slow to recover--STR, N=12). The difference in the proportions of recovery achieved at 1-week for FTR (0.93,95% CI, 0.75-1.11) vs. STR (-0.07,95% CI, -0.30-0.16) patients was highly significant (p<0.001). CONCLUSION: Patients who recover over the first 3 months follow distinct trajectories, either achieving approximately 90% of their total recovery by 1 week or making marginal recovery early, and only later achieving their total expected recovery ( Fig ). These findings have important implications for rehabilitation and predicting recovery after stroke. Future work must address the biological correlates of this dichotomy.