Early imaging correlates of subsequent motor recovery after stroke

Abstract

Objective: To determine whether functional magnetic resonance imaging activation obtained in the first few days after stroke correlates with subsequent motor recovery. Methods: Twenty-three patients with hemiparesis after first-time stroke were scanned at 2.0 Ϯ 0.9 days while performing a simple motor task. We defined recovery as the change in Fugl-Meyer score from time of scan to approximately 3 months later (90 Ϯ 8 days). We performed three different tests to assess correlations between brain activation and change in Fugl-Meyer score: (1) multivariate (most sensitive to spatially diffuse activation); (2) voxel-wise Statistical Parametric Mapping (most sensitive to focal activation), and (3) primary motor cortex region-of-interest analysis (most sensitive to average activation within this region). All tests controlled for initial stroke severity and lesion volume, as well as other established clinical variables. Results: The multivariate test was significant [F (595, 4,934) ϭ 1.93; p Ͻ 0.001]. The Statistical Parametric Mapping test detected two small clusters of focal activity located in the ipsilesional postcentral gyrus and cingulate cortex ( p Ͻ 0.05, corrected). The region-of-interest test was not significant. Interpretation: There is a pattern of brain activation present in the first few days after stroke, of which the postcentral gyrus and cingulate cortex are a part, that correlates with subsequent motor recovery. This result suggests that there are recovery processes engaged early after stroke that could provide a target for intervention.Ann Neurol 2009;65:596 -602 There is unexplained variability in the extent to which patients recover after stroke, particularly from the reference point of the first few days after onset. Among studies that track motor impairment and recovery, only 30 to 50% of the variance of recovery is explained by the most commonly reported predictors: lesion volume and initial stroke severity.1,2 We hypothesized that functional imaging early after stroke could provide information over and above initial severity and lesion volume about the degree of subsequent recovery. Several prior functional imaging studies have reported altered brain activation patterns in patients at various stages of motor recovery after stroke.3-6 These studies describe brain activation related to concurrent recovered performance at the time of scanning that differs to varying degrees from what is seen in age-matched control subjects. In this study, we used functional imaging to ask a specific and unique question about motor recovery after stroke: Can functional imaging in the early period after stroke detect brain activation related to subsequent recovered performance? Should such activation be identified, then it could serve as a physiological target for intervention (eg, noninvasive brain stimulation) in this early time period.To investigate whether brain activation early after stroke can be correlated with subsequent recovery, we scanned patients approximately 48 hours after stroke using functional ma...

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Upper Limb Recovery After Stroke Is Associated With Ipsilesional Primary Motor Cortical Activity

“…11 At more chronic stages, enhanced negative coupling between contralesional and ipsilesional-MI is seen in patients with poorer outcome. 34 The higher the activity in those areas, the poorer the associated recovery, 3,7 suggesting that contralesional motor activity might not represent functionally relevant processes. Indeed a recent resting state stroke study using graph theory showed that stronger engagement of the contralesional hemisphere was associated with ineffective motor reorganization.…”

Modulation of Neural Plasticity as a Basis for Stroke Rehabilitation

“…16,17 Notably, a recent functional magnetic resonance imaging study has shown that the pattern of brain activation present in the early phase after stroke could be predictive of subsequent recovery of motor functions. 18 …”