Motor imagery learning across a sequence of trials in stroke patients

Article type: Research Article

Authors: Lee, Minji^a | Park, Chang-hyun^b | Im, Chang-Hwan^c | Kim, Jung-Hoon^c | Kwon, Gyu-Hyun^d | Kim, Laehyun^d | Chang, Won Hyuk^b | Kim, Yun-Hee^{a; b; *}

Affiliations: [a] Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Irwon-dong, Gangnam-gu, Seoul, Republic of Korea | [b] Department of Physical and Rehabilitation Medicine, Center for Prevention & Rehabilitation, Heart Vascular and Stroke, Samsung Medical Center, Sungkyunkwan University School of Medicine, Irwon-dong, Gangnam-gu, Seoul, Republic of Korea | [c] Department of Biomedical Engineering, Hanyang University, Haengdang 1-dong, Seongdong-gu, Seoul, Republic of Korea | [d] Center for Bionics, Korea Institute of Science and Technology (KIST), Wolgok 2-dong, Seongbuk-gu, Seoul, Republic of Korea

Correspondence: [*] Corresponding author: Yun-Hee Kim, MD, PhD, Department of Health Sciences and Technology, Samsung Advanced Institute for Health Science and Technology, Department of Physical and Rehabilitation Medicine, Center for Prevention & Rehabilitation, Heart Vascular and Stroke, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Republic of Korea. Tel.: +82 2 3410 2824/2818; Fax: +82 2 3410 0052; E-mails: yun1225.kim@samsung.com, and yunkim@skku.edu.

Abstract: Purpose: In brain–computer interfaces (BCIs), electrical brain signals during motor imagery are utilized as commands connecting the brain to a computer. To use BCI in patients with stroke, unique brain signal changes should be characterized during motor imagery process. This study aimed to examine the trial-dependent motor-imagery-related activities in stroke patients. Methods: During the recording of electroencephalography (EEG) signals, 12 chronic stroke patients and 11 age-matched healthy controls performed motor imagery finger tapping at 1.3 sec intervals. Trial-dependent brain signal changes were assessed by analysis of the mu and beta bands. Results: Neuronal activity in healthy controls was observed over bilateral hemispheres at the mu and beta bands regardless of changes in the trials, whereas neuronal activity in stroke patients was mainly seen over the ipsilesional hemisphere at the beta band. With progression to repeated trials, healthy controls displayed a decrease in cortical activity in the contralateral hemisphere at the mu band and in bilateral hemispheres at the beta band. In contrast, stroke patients showed a decreasing trend in cortical activity only over the ipsilesional hemisphere at the beta band. Conclusions: Trial-dependent changes during motor imagery learning presented in a different manner in stroke patients. Understanding motor imagery learning in stroke patients is crucial for enhancing the effectiveness of motor-imagery-based BCIs.

Keywords: Motor imagery, stroke, electroencephalography, brain-computer interfaces, SPM

DOI: 10.3233/RNN-150534

Journal: Restorative Neurology and Neuroscience, vol. 34, no. 4, pp. 635-645, 2016