Near-infrared spectroscopy and electroencephalography to assess and train cortical activation during motor tasks

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Abstract

Summary The primary overarching goals of our research program are to understand the mechanisms underlying motor incoordination in children and adults with childhood onset brain injuries and childhood onset peripheral injuries and to design more effective therapies to improve motor functioning. This protocol involves the use of mobile brain imaging techniques for both of these goals. This past year, we have two major accomplishments: 1) we published a manuscript reporting on the dynamic changes in EEG-based brain connectivity during a button press task comparing children with CP and an age-matched cohort without CP; 2) refined the design of our EEG-based biofeedback system, validated its design and completed initial testing for feasibility in participants with CP. Objective The objectives of this protocol are to: 1) systematically compare cortical activation patterns associated with specified motor and sensory tasks in healthy children and adults to those with unilateral or bilateral childhood-onset brain injury, and 2) pilot the use of EEG as a brain biofeedback device in children with childhood-onset brain or peripheral injuries. The first objective is observational only, the second objective includes a pilot intervention. Study population The childhood-onset brain injury group will consist of up to 120 individuals (5 years and above) across all the different studies included under this protocol. For the observational studies, we collect children with and without cerebral palsy because little is known about the brain activation during motor tasks in typically developing children, much less those with brain injuries. Results We are able to identify differences in both motor performance and brain activation during several motor tasks in cohorts with and without CP. EEG activation magnitudes are also correlated with motor skill; however, sometimes greater magnitude is associated with better skill whereas in some cases, the opposite is true. Similarly, higher coherence in CP has been associated with greater functional limitation. These relationships are affected by the amount of residual brain tissue in specific areas, the degree of cortical reorganization and abnormal intracortical mapping (e.g. recruiting more muscles and therefore brain areas than needed to perform a task) A second result is the development of an operational neurofeedback system that uses a person's own EEG signal when they attempt to move (dorsiflex their ankle) to activate a functional electrical stimulation device to assist with the movement and augment the sensory input to the sensorimotor pathways to strengthen them during training. The desired outcomes are improvement in selective control of ankle motion and/or speed, and evidence of this improved ankle control during walking. In the prior reporting period, we evaluated the results from four participants and were not satisfied with the detection accuracy. In this current reporting period, we modified the protocol that instructs the participants on when to move their ankle by adding a clearer visual interface and incorporating both “go” and “no-go” trials. We also modified the real-time movement intent detection algorithm to increase detection accuracy. This revised system was evaluated in one healthy control (with a second currently enrolled) and two participants with CP. The initial results validated the revised protocol design and demonstrated movement intent detection accuracy within our acceptable target range (greater than 70%). Once we complete testing of this in healthy controls, we will resume our study pilot intervention study in individuals with CP.