A Brain Computer Interface (BCI) driven Paired Associative Stimulation (PAS) protocol: A rehabilitation intervention for people with stroke.

The BCI-PAS intervention will be delivered three times per week for 4 weeks. In the first session of each week, electroencephalography (EEG) will be recorded using an electrode cap, while subjects perform active ankle dorsiflexion of their affected leg, in time with a visual cue. The EEG is then analysed and the peak negativity of the movement related cortical potential (MRCP) is determined. This timing is then used to inform the timing of the BCI-PAS intervention for that week. The BCI-PAS is delivered three times each week for 4 weeks, by a trained Research Assistant. During each intervention session, the subject completes 50 repetitions of cued active ankle dorsiflexion of the affected leg. During each repetition of ankle dorsiflexion, a single pulse of electrical stimulation (pulse width 1ms) is delivered to the deep branch of the common peroneal nerve at the intensity required to produce a palpable twitch in the tibialis anterior tendon. Each pulse of electrical stimulation is timed to arrive in the motor cortex at the point of peak negativity of the MRCP. The BCI-PAS intervention takes approximately 15 minutes, with additional time required for setting up the electrical stimulation.