The effects of non-invasive brain stimulation on motor re-learning in people with chronic stroke

The study involves four sessions in total: three rehabilitation sessions on a treadmill using transcranial direct current stimulation (tDCS) intervention over three consecutive days and one post-intervention assessment after one week. In the first session, prior to walking on the treadmill, comfortable walking speed and walking asymmetry during over-ground walking will be determined. During treadmill walking, kinematic data will be measured through computerized gait analysis that will record 3-dimensional position data from reflective markers placed on legs. The participant’s walking will be assessed during three phases: 1) baseline phase, where both the belts will move at the same speed for 2 minutes; 2) adaptation phase, where both the belts will move at different speeds for 15 minutes; and 3) de-adaptation phase, where the belts will move at same speed again for 3 minutes. During adaptation phase, tDCS intervention will be delivered by a direct current stimulator (Magstim Co, UK) via electrodes placed on the back of the head (active electrode on the cerebellum) and on the cheek (reference electrode). The current will be slowly ramped up to 2 mA over 30 seconds, held constant at 2 mA for 15 minutes and then decreased over 30 seconds at the end of the stimulation. The primary outcome measure will be step length asymmetry measured at post-intervention assessment after one week. To determine the translation of effects to over-ground walking, over-ground walking asymmetry will be assessed after three days and one week. Each session will take approximately two hours (90 minutes-assessment and setting up, 20 minutes-rehabilitation) and will be held at the Running and Cycling clinic, AUT Millennium Institute.