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

Abstract

Background and Purpose-Although neuroimaging studies have revealed specific patterns of reorganization in the sensorimotor control network after stroke, their role in recovery remains unsettled. To review the existing evidence systematically, we performed activation likelihood estimation meta-analysis of functional neuroimaging studies investigating upper limb movement-related brain activity after stroke. Methods-Twenty-four studies using sensorimotor tasks in standardized coordinates were included, totaling 255 patients and 145 healthy controls. Across the entire brain, we compared task-related activity patterns in good and poor recovery and assessed the magnitude of spatial shifts in sensorimotor activity in cortical motor areas after stroke. Results-When compared with healthy controls, patients showed higher activation likelihood estimation values in contralesional primary motor soon after stroke that abated with time, but were not related to motor outcome. The observed activity changes were consistent with restoration of typical interhemispheric balance. In contrast, activation likelihood estimation values in ipsilesional medial-premotor and primary motor cortex were associated with good outcome, reorganization that may reflect vicarious processes associated with ventral activity shifts from BA4a to 4p. In the anterior cerebellum, a novel finding was the association of poor recovery with increased vermal activity, possibly reflecting behaviorally inadequate compensatory strategies engaging the fastigio-thalamo-cortical and corticoreticulospinal systems. Conclusions-Activity in ipsilesional primary

Characterizing relationships of DTI, fMRI, and motor recovery in stroke rehabilitation utilizing brain-computer interface technology

“…A recent study shows evidence that DTI measures may be used as potentially predictive of individual recovery in stroke patients receiving newer neurorehabilitative therapies, such as transcranial direct current stimulation (Lindenberg et al, 2012). Besides DTI, fMRI is another non-invasive neuroimaging technique that has been used to gain better understanding of the processes of brain functional reorganization accompanying motor recovery after stroke (Calautti and Baron, 2003; Riecker et al, 2010; Garrison et al, 2013; Havsteen et al, 2013; Favre et al, 2014; Zhang et al, 2014). Measures derived from fMRI have also been shown as potential biomarkers to track recovery, with correlations between functional changes and fMRI measures demonstrated with treatments such as Brain-Computer Interface (BCI) therapy (Mukaino et al, 2014), constrain-induced movement therapy (Murayama et al, 2011; Kononen et al, 2012) and motor imagery therapy (Sun et al, 2013).…”

Measuring motor-training induced neuroplasticity using diffusion and functional MRI: a sensitive, pathology-robust approach

“…57,105,126 Similarly, for stroke, activation of the ipsilateral primary motor cortex has been associated with both good and poor behavioural outcomes. 114 Such variability can render the physiological significance of t-fMRI differences unclear.…”

“…106,114 Reproducibility studies have demonstrated that even well-controlled longitudinal t-fMRI studies of normal subjects likely have a high degree of intrasubject measurement error 131 and require at least 20 subjects per group to perform reliable and sensitive group analyses. 97 The higher degree of variability seen within brain injury cohorts means that required numbers are likely to be substantially higher.…”

“…112 Both stroke and unilateral CP patients, however, regularly demonstrate robustly bilateral activation. 105,113,114 These balances of activation are typically calculated as laterality index (LI):…”

“…114 Over time, these values become more positive 111,114 but do not typically return completely to "normal" values, 115 even in well-recovered patients. 110,116 In chronic stroke patients, LI values are often, 117,118 but not always, 119 reported to shift toward the lesioned hemisphere in response to rehabilitative therapy.…”