The Role of Baseline Functional MRI as a Predictor of Post-Stroke Rehabilitation Efficacy in Patients with Moderate to Severe Upper Extremity Dysfunction

Abstract

Introduction: Upper extremity impairment is one of the common complications following a stroke. There are numerous rehabilitation strategies to address this problem. However, patients with moderate to severe upper limb disabilities respond differently to the same rehabilitation protocol. Apart from each patient’s unique characteristics, there are specific brain reorganizing patterns that affect the post-rehabilitation response rate. Functional magnetic resonance imaging (fMRI) determines brain activation area and connectivity patterns and has been utilized in the neurorehabilitation field. Material and Methods: Six stroke patients who suffered from moderate to severe upper extremity dysfunction were enrolled in this pilot study. Upper extremity function tests including the Fugl-Meyer assessment test for upper extremity (FMA-UE), and Wolf Motor Function Test (WMFT) were utilized before and after completing an intensive rehabilitation. The intensive rehabilitation program was conducted one hour a day for five days per week for four weeks. Moreover, fMRI was applied before initiating rehabilitation. The regions of interest were those associated with movement, including Brodmann areas (BA) BA1-BA6. Results: Six stroke patients in the sub-acute to chronic phase and ages ranging between 33 - 75 years were enrolled. All patients showed an improvement in upper limb function after four weeks of rehabilitation. Patient number one (Pt1) had the most improvement in FMA-UE, while patient number four (Pt4) recovered the most measured by WMFT. Pt1 demonstrated increased activity in all contralesional regions, whereas Pt4 had only increased activity in ipsilesional areas. Furthermore, patients with greater activation in the ipsilesional BA6 (Pt1, Pt4, Pt5, and Pt6) had better responses to the rehabilitation therapy. Conclusion: Patients with greater activation in the baseline fMRI, particularly ipsilesional BA6, had a better response to the intensive rehabilitation therapy. However, the patients with the most severe hand dysfunction showed lesser improvement despite the same brain activity as others in the initial fMRI.