Page 304 - MEGIN Book Of Abstracts - 2023

ABSTRACT Recent findings indicate that measures de- ences, College of Medicine, Chang Gung University, Taoyuan,
rived from resting-state magnetoencephalography (rs- Taiwan; Healthy Aging Research Center, Chang Gung Uni-
MEG) are sensitive to cortical dysfunction in post-stroke versity, Taoyuan, Taiwan; Department of Psychiatry, Chang
aphasia. Spectral power and multiscale entropy (MSE) Gung Memorial Hospital, Linkou, Taiwan; Department of
measures show that left-hemispheric areas surround- Medical Research, Hsinchu MacKay Memorial Hospital,
ing the stroke lesion (perilesional) exhibit pathological Hsinchu, Taiwan; Department of Physical Medicine and Re-
oscillatory slowing and alterations in signal complexity. habilitation, Chang Gung Memorial Hospital, Linkou, Taiwan;
In the current study, we tested whether individually- School of Medicine, College of Medicine, Chang Gung Univer-
targeted high-definition transcranial direct current sity, Taoyuan, Taiwan; Department of Occupational Therapy
stimulation (HD-tDCS) can reduce MEG abnormalities and Graduate Institute of Behavioral Sciences, College of
and transiently improve language performance. In elev- Medicine, Chang Gung University, Taoyuan, Taiwan; Healthy
en chronic aphasia survivors, we devised a method to Aging Research Center, Chang Gung University, Taoyuan,
localize perilesional areas exhibiting peak MSE abnor- Taiwan; Department of Physical Medicine and Rehabilitation,
malities, and subsequently targeted these areas with Chang Gung Memorial Hospital, Linkou, Taiwan. Electronic
excitatory/anodal-tDCS, or targeted the contralateral address: ywhsieh@mail.cgu.edu.tw
homolog areas with inhibitory/cathodal-tDCS, based
on prominent theories of stroke recovery. Pathologi- OBJECTIVE This study aimed to investigate the differ-
cal MEG slowing in these patients was correlated with ential effects of bilateral and unilateral mirror therapy
aphasia severity. Sentence/phrase repetition accuracy (MT) on motor cortical activations in stroke patients by
was assessed before and after tDCS. A delayed word magnetoencephalography (MEG).
reading task was administered inside MEG to assess
tDCS-induced neurophysiological changes in relative METHODS Sixteen stroke patients and 16 right-handed
power and MSE computed on the pre-stimulus and healthy volunteers were recruited. All participants were
delay task time windows. Results indicated increases required to perform 4 conditions: resting, no mirror
in repetition accuracy, decreases in contralateral theta with bilateral hand movements (Bilateral-No mirror),
(4-7 Hz) and coarse-scale MSE (slow activity), and mirror with bilateral hand movements (Bilateral-Mirror)
increases in perilesional low-gamma (25-50 Hz) and and mirror with unilateral hand movements (Unilateral-
fine-scale MSE (fast activity) after anodal-tDCS, indicat- Mirror). Beta oscillatory activities in the primary motor
ing reversal of pathological abnormalities. RsMEG may cortex (M1) were collected during each condition using
be a sensitive measure for guiding therapeutic tDCS. MEG. The percentage change of beta oscillatory activity
was calculated for each condition to correct the base-
Scientific reports (2020), Vol. 10, No. 1 (33184382) (6 line differences.
citations)
RESULTS In the stroke group, the percentage change
of M1 beta oscillatory activity significantly decreased
Cortical neural activity evoked by bilateral and more in the Bilateral-Mirror condition than in the
unilateral mirror therapy after stroke (2020) Bilateral-No mirror and Unilateral-Mirror conditions.
In the healthy group, no significant differences in the
Tai, Ruei-Yi; Zhu, Jun-Ding; Cheng, Chia-Hsiung; Tseng, percentage change of beta oscillatory activity were
Yi-Jhan; Chen, Chih-Chi; Hsieh, Yu-Wei found among the 3 conditions. Further, a significant
difference in the percentage change of beta oscillatory
Department of Neurology, Taipei Medical University Hospital, activity only in the Bilateral-Mirror condition was found
Taipei, Taiwan; Taipei Neuroscience Institute, Taipei Medical between the 2 groups.
University, Taipei, Taiwan; Institute of Brain Science, National
Yang-Ming University, Taipei, Taiwan; Department of Oc-
cupational Therapy and Graduate Institute of Behavioral Sci-

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