Biomarkers of Early STroke recovery (BEST)

More than 100,000 people in the UK have a stroke each year. Two thirds of those who leave hospital will have life altering disabilities. Previous research suggests that only half of patients with the most severe upper limb impairment will recover proportionally, whereas the other half will not. These two groups are clinically identical, indicating that there are other undetermined factors imperative for the recovery process. Eliciting upper limb motor evoked potentials (MEPs), produced by transcranial magnetic stimulation (TMS), indicates whether patients have a functional corticospinal tract. Previous research suggests that MEP+ severe patients are likely to recover but it cannot predict the outcome of MEP- patients. To understand this process further, we must uncover the neurobiological factors responsible for the recovery process itself. From animal studies, we know that plasticity mechanisms are essential for post-stroke spontaneous biological recovery. Within this, the GABAergic system has been shown to have a key role in driving plasticity during recovery. In humans, magnetoencephalography (MEG) detects changes in the magnetic field produced by neuronal populations, generated by network level excitatory and inhibitory connections. One MEG biomarker, the post-sensory beta rebound is thought to indicate the level of cortical GABAergic activity. In this study, we will record neuronal oscillations such as the beta rebound, MEPs and structural MRI from acute stroke patients within 2 weeks of stroke and 3-months after. Using MEP presence and MEG biomarkers, alongside structural and clinical information, we aim to predict upper limb recovery at 3 months post stroke, to a higher accuracy than with MRI and initial impairment alone. Being able to stratify acute stroke patients into recoverers and nonrecoverers will allow us to provide more tailored rehabilitation interventions, increasing the prospect of upper limb recovery for severe stroke survivors."