Use of neurophysiological measures to estimate and influence change in motor function

Frequent assessment of motor function would contribute towards personalization of therapeutic activities for stroke survivors. This study aimed to propose a pragmatic motor assessment tool that could facilitate frequent assessments towards recovery of lost function during chronic phase. We focused our investigation on the use of EEG-based resting state functional connectivity (FC) for this purpose. The first phase investigated the suitability of FC for accurate estimation of motor impairment in stroke survivors. We selected phase synchronization as a measure of FC and Fugl-Meyer assessment for upper extremities (FMU) as a measure of impairment. We used projection algorithms to develop models for estimating FMU from FC. We showed cross-validated R2 of 0.97 and an RMS error of 1.9 on FMU scale. The proposed method showed promise as a practical tool for frequent assessments of motor function. There is diminished incentive for frequent assessments, however, if FC could only estimate large changes in function, as is the case with FMU. The second phase of our study investigated the ability of the proposed algorithms in estimating small incremental changes in motor function. Using objective measures of motor skill in healthy participants, we showed 98% accuracy in estimating small longitudinal changes in skill, thereby improving the incentive for frequent assessments. The high estimation accuracy of our proposed method presented an opportunity to assess bidirectional interactions between FC and motor function. The third phase of our study investigated the prospects of inducing a change in motor skill by influencing FC. We selected mental imagery as the mechanism to influence FC and provided real-time neurofeedback on the selected connectivity channels to guide the mental imagery. We showed over 20% improvement in motor skill of a healthy individual through neurofeedback training alone. Our proposed method showed promise in facilitating an individualized approach towards improvement of motor function that could complement the conventional therapeutic activities. It also showed potential for providing an accurate assessment of motor impairment, while addressing the challenges associated with the availability and expertise of examiners. It promotes frequent assessments of motor function and personalization of therapeutic activities for stroke survivors in chronic phase.