Alternative Motor Task-Based Pattern Training with a Digital Mirror Therapy System Enhances Sensorimotor Signal Rhythms Post-Stroke

Abstract

Mirror therapy (MT) facilitates motor learning and induces cortical reorganization and motor recovery from stroke. Visual feedback during MT is thought to induce cortical reorganization, improving motor recovery in weak or paralyzed limbs. In the present study, we combined task-specific training, which is used in clinical stroke rehabilitation, with a high-resolution and first-person perspective digital mirror therapy (DMT) system. During DMT, EEG recordings were obtained from the standard C3, C4, and Cz scalp sites. Electrode pairs covered the supplementary motor area and the contralateral (active hand) and ipsilateral (non-active/mirrored hand) primary sensorimotor hand areas. We compared signals produced by individuals in three training conditions: (1) No mirror visual feedback (no-MVF), (2) bilateral synchronized task-based mirror visual feedback training (BMVF), and (3) reciprocal task-based mirror visual feedback training (RMVF). We sought to evaluate the feasibility of the DMT system for activating cortical areas in three different conditions in healthy and stroke adults. Time-dependent event-related desynchronization (ERD) signal amplitude was recorded from C3, C4, and Cz. Two-way and one-way repeated measures ANOVA was used to compare differences between the three conditions. We found that Cz area P0 amplitudes of BMVF and RMVF participants increased by 1.7 and 1.8-fold compared to no-MVF in stroke participants, respectively. In stroke patients we also found significantly more activation of the motor cortex with RMVF pattern than BMVF and no-MVF in Cz area P2 amplitudes. With both BMVF and RMVF, subjects were able to continuously predict and move their upper extremities in the absence of a virtual upper extremity, which may require estimation of target points and thus induce proprioceptive integration of controlling brain networks. These asynchronous alternative motor task-oriented and proprioceptive integrated exercises by using a DMT system activated and enhanced the extended motor cortex compared to synchronize task-based motion and without MVF, resulting in cerebral motor cortical facilitation.