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. We applied the new digital mirror therapy (DMT) system to compare the cortical activation under the three visual feedback conditions: (1) no mirror visual feedback (NoMVF), (2) bilateral synchronized task-based mirror visual feedback training (BMVF), and (3) reciprocal task-based mirror visual feedback training (RMVF). During DMT, EEG recordings, including time-dependent event-related desynchronization (ERD) signal amplitude in both mu and beta bands, were obtained from the standard C3 (ispilesional hemisphere, IH), C4 (contralesional hemisphere, CH), and Cz scalp sites (supplementary motor area, SMA). The entire ERD curve was separated into three time-phases: P0 (−2 to 0 s), P1 (0 to 2 s), and P2 (2 to 4 s). Four-way and subsequent repeated-measures analyses of variance were used to examine the effects of group (stroke vs. control group), test condition (NoMVF, BMVF, and RMVF), time-phase (P0, P1, and P2), and brain area (IH, CH, SMA) on the ERD areas (%) in mu and beta bands. For the mu band, generally, ERD areas (%) were larger in the control than in the stroke group. The ERD areas (%) were largest under the RMVF condition, followed by BMVF and NoMVF conditions. Similar results were found in the beta bands. The main effects of group, time-phase, and test condition on the ERD areas (%) were significant for the three brain areas, except the main effect of group in the SMA (Cz) and CH (C4) brain area. The ERD areas (%) were larger in the control than in the stroke group. The ERD area (%) was significantly larger during P1 than during P0 and P2 (ps < 0.02), and during P2 than during P0 (ps < 0.01). The ERD area (%) under the RMVF condition was significantly larger than that under the BMVF condition and NoMVF condition (ps < 0.05). The present study suggests that cortical activation particularly in the SMA (Cz) of the brain increases in the RMVF condition in both healthy subjects and stroke patients. This result supports the hypothesis that stroke patients may benefit from RMVF training.

Event-Related Desynchronization During Mirror Visual Feedback: A Comparison of Older Adults and People After Stroke

“…The results of this study show that there was an MVFinduced ERD attenuation in the high and low beta bands, and that the rhythm suppression was greater over the contralateral hemisphere (i.e., contralesional in stroke) than it was over the ipsilateral hemisphere in the low beta in stroke participants. This finding is consistent with the results of another study using magnetoencephalography (MEG) that the ERD in M1 beta decreased more in the bilateral mirror condition than in the bilateral no-mirror and unimanual mirror conditions (Tai et al, 2020), and that the ERD areas in both the alpha and beta were larger under the reciprocal mirror condition, followed by bilateral and no-mirror conditions (Chang et al, 2019). In a recent MEG study (Rossiter et al, 2015), similar results of movement-related beta desynchronization were found in patients and their healthy controls, but those observations differed from the results of another study (Frenkel-Toledo et al, 2013) that found in an EEG analysis a more pronounced suppression over the right hemisphere than over the left hemisphere sites during observation of action, regardless of the hand that moved (right or left hand).…”

Associated Mirror Therapy Enhances Motor Recovery of the Upper Extremity and Daily Function after Stroke: A Randomized Control Study

“…Despite proving the feasibility of combining bilateral symmetrical tasks with MT, patients were asked to concentrate on the reflection side of the mirror and could not ensure the participation of the paretic side. New setups for MT conquered the limitations of the conventional mirror, for instance, the camera technique-based MT proposed by Lee et al, which realized MVF effect delay and bilateral movements [ 22 , 24 ]. We previously put forward novel camera technique-based MVF [ 21 ].…”

“…Compared to usual care, camera technique-based MVF was proven to enhance the motor impairment of the upper extremity after stroke [ 22 , 25 ]. In line with the results of previous studies, the improvements in motor impairment measured by FAM-UL were observed in both groups after the intervention, and patients in the EG were improved more significantly than the CG.…”

“…To overcome the limitations of the traditional MT, researchers have proposed novel mirror setups. Camera technique-based MVF, which offered bilateral visual feedback, was one of those, and previous researches have been verified that camera technique-based MVF can promote the functional recovery of stroke [22][23][24].…”

Development and user experience of an innovative multi-mode stroke rehabilitation system for the arm and hand for patients with stroke

“…Given the current advances in digital imaging technology, real-time video-captured images and computer-mediated visual feedback and stimuli have been developed and widely used in stroke rehabilitation 17 – 23 . Recently, some studies have recorded movements executed mainly by the non-affected hand of patients, immediately transformed the actions of the non-affected hand, and presented them on a screen or in goggles via cameras, webcams, or virtual reality technology 17 , 19 , 21 , 23 – 25 . This approach using real-time video-captured images broadens the diversity of movements and functional tasks and allows the users to record individual videos by themselves, which helps to overcome some limitations of conventional MT and AOT.…”