Cortico-Muscular Coherence Modulated by High-Definition Transcranial Direct Current Stimulation in People With Chronic Stroke

• Published in: IEEE transactions on neural systems and rehabilitation engineering Vol. 27; no. 2; pp. 304 - 313
• Main Authors: Bao, Shi-Chun, Wong, Wan-Wa, Leung, Thomas Wai Hong, Tong, Kai-Yu
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.02.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adult; Algorithms; Anodes; Cathodes; Chronic Disease; Coherence; Contraction; Cortex (motor); Cortico-muscular coherence; Direct current; EEG; Electrical stimulation of the brain; Electrical stimuli; Electrodes; Electroencephalography; Electromyography; Entropy; ESB; Female; high-definition; Humans; Isometric; Isometric Contraction; Male; Middle Aged; Motor Cortex - physiopathology; Muscle contraction; Muscle, Skeletal - physiopathology; Neuromodulation; Physical Therapy Modalities; Power spectral density; Rehabilitation; Single-Blind Method; Stimulation; Stroke; Stroke - physiopathology; Stroke Rehabilitation - instrumentation; Stroke Rehabilitation - methods; Task analysis; transcranial direct current stimulation; Transcranial Direct Current Stimulation - instrumentation; Transcranial Direct Current Stimulation - methods; Wrist
• ISSN: 1534-4320; 1558-0210; 1558-0210
• DOI: 10.1109/TNSRE.2018.2890001

High-definition transcranial direct current stimulation (HD-tDCS) is a potential neuromodulation apparatus for stroke rehabilitation. However, its modulatory effects in stroke subjects is still not well understood. In this paper, the offline modulatory effects of HD-tDCS on the ipsilesional primary motor cortex were investigated by performing wrist isometric contraction tasks before and after HD-tDCS in eleven unilateral chronic stroke subjects using a synchronized HD-tDCS and electroencephalogram/electromyography measurement system. This paper is a randomized, single blinded, and sham-controlled crossover study. Each subject randomly received three HD-tDCS (anode, cathode, and sham) with at least one-week washout period. Online feedback-guided medium-level wrist isometric contraction tasks were conducted for the affected upper limbs before stimulation and 10, 30, and 50 min after the end of 10-min 1-mA HD-tDCS. The characteristics of corticomuscular coherence (CMC), cortical oscillation power spectral density, and power spectral entropy were analyzed during tasks and compared across all sessions and stimulation conditions. Anode HD-tDCS induced significant CMC changes in stroke subjects, while cathode and sham stimulation did not induce significant CMC changes. The largest neuromodulation effects were observed at 10 min immediately after anodal HD-tDCS.