Stroke is one of the leading causes of death worldwide, and while morbidity rates in Ireland have substantially decreased in recent years, rehabilitation of survivors has not improved concurrently. In the proposed research, a state-of-the art therapy to improve upper limb function in stroke survivors will be developed, based upon a novel form of brain-computer interface. Using this approach, magnetic pulses are applied to the scalp over the location on the motor cortex that controls the arm and hand, via Transcranial Magnetic Stimulation (TMS). This evokes a twitch in the stroke-affected muscles (motor evoked potential, MEP), which is recorded using electromyography. The amplitude of this twitch provides a read-out of the excitability of the neural pathways connecting the brain to the muscle. Following stroke, cortico-spinal excitability is dramatically reduced, but recent evidence suggests that its resolution to normal levels may indicate an important neurobiological mechanism of recovery. Using our TMS-neurofeedback approach, the amplitude of MEPs are displayed to the patient in real-time, with rewarding visual and auditory feedback incorporated in a game-like display, to train them over a period of several days to make the amplitudes larger. The aim is to develop the concept of TMS neurofeedback into a suitable rehabilitation intervention for stroke patients, by testing different variants of the protocol and measuring outcomes such as functional improvements, and perceived benefit reported by the users. Additionally, as re-myelination of the corticomotor structural pathways has been proposed as a key recovery mechanism in this process, we will quantify microstructural integrity of the white matter tracts in the brain pre and post neurofeedback training. We hypothesise that patients in an experimental group receiving TMS neurofeedback will demonstrate changes in corticospinal excitability following training, that will be correlated with functional improvements and re-myelination of motor pathways, compared to a control group.
