Potential for Recovery of Voluntary Finger Extension After Stroke

Stroke patients with absent voluntary finger extension (VFE) 6-months after stroke are not expected to recover hand function. However, experience from the Queen Square Upper Limb neurorehabilitation service contradicts this view. In this study, we will identify the characteristics of those chronic stroke patients who regain previously absent VFE. Hundred chronic stroke patients will be recruited with absent/negligible VFE in an external pilot and feasibility study. Transcranial magnetic stimulation will be used to determine the functional integrity of descending white matter pathways. Corticospinal tract integrity to finger extensor muscles will be based on whether motor-evoked potentials are present (MEP+) or absent (MEP-). Reticulospinal tract activity will be assessed by measuring ipsilateral MEP amplitudes and the Start-React response. All patients will then receive 3-months of neuromuscular electrical stimulation plus home exercise, designed to strengthen wrist/finger extensors, reduce spasticity and increase corticospinal excitability. The primary outcome measure will be restoration of VFE. It is predicted that VFE will be restored in MEP+ but not MEP- patients. MEP- patients will have higher reticulospinal tract activity associated with spasticity. Restoration of VFE will allow patients to engage in evidence-based upper limb training to improve function e.g. constraint induced movement therapy or repetitive task training.