Moving a Paralyzed Hand Through Use of a Brain-Computer Interface

Objective: Individuals who have suffered a stroke or traumatic brain injury (TBI) may benefit from the development of new rehabilitative interventions that can improve motor recovery after injury. The purpose of this protocol is to test the hypothesis that oscillatory brain activity that originates in the affected hemisphere in the form of desynchronization of Mu-rhythm of patients with chronic stroke or TBI can be used to drive movements of an orthosis attached to a paralyzed hand through a Brain Computer Interface (BCI). Mu-rhythm is a type of brain wave activity that originates in the sensorimotor areas of the brain that can be controlled voluntarily; it is present in the affected hemisphere of stroke patients and can be used to control the hand prostheses through the BCI interface. Control of Mu-rhythm amplitudes by volition requires training since it does not happen spontaneously. A proof-of-principle sub-experiment will test the hypothesis that in stroke survivors non-invasive cortical stimulation of the ipsilesional primary motor cortex (M1) will facilitate learning to control a hand orthosis through a BCI device. This is the purpose of the training: to teach the subject to control Mu-rhythms. Study population: The study population will consist of individuals with chronic stroke or TBI that have virtually no movement of their paretic hand and age- and gender- matched healthy volunteers. Healthy volunteers, which may include the age- and gender- matched volunteers, will be recruited to refine instructions given to patients. Design: This is primarily an intraindividual comparison study, designed to determine if this brain-computer interface (BCI) approach contributes to drive grasping motions through a BCI interface and hand-orthosis. To test the effect of non-invasive cortical stimulation 21 stroke patients will be randomly assigned to three groups (group A, anodal stimulation; group B, cathodal stimulation; group C, sham stimulation). Study of normal volunteers will contribute to (a) set up of the experiment, (b) identifying differences in the training time required to modulate Mu-rhythm in healthy volunteers and patients and (c) to isolate training effects as measured by TMS and fMRI on the healthy brain from training effects on brains affected with stroke or TBI. This information will be treated descriptively within the framework of this protocol but it is also important for designing future studies. Outcome measures: Behavioral endpoint measure: ability to drive the paralyzed hand orthosis in flexion and extension motions using Mu-rhythm. Physiological endpoint measures: peak fMRI activity in the hand knob representation, and corticomotor excitability as tested with TMS and MEG in ipsilesional and contralesional hand knob representations. Normal volunteers will undergo evaluation of the same physiological endpoint measures as patients.