Decoding Attempted Hand Movements in Stroke Patients Using Surface Electromyography

Date
2020-11-26
Authors
Jochumsen, M
Niazi, IK
Rehman, MZU
Amjad, I
Shafique, M
Gilani, SO
Waris, A
Supervisor
Item type
Journal Article
Degree name
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI AG
Abstract

Brain‐ and muscle‐triggered exoskeletons have been proposed as a means for motor training after a stroke. With the possibility of performing different movement types with an exoskeleton, it is possible to introduce task variability in training. It is difficult to decode different movement types simultaneously from brain activity, but it may be possible from residual muscle activity that many patients have or quickly regain. This study investigates whether nine different motion classes of the hand and forearm could be decoded from forearm EMG in 15 stroke patients. This study also evaluates the test‐retest reliability of a classical, but simple, classifier (linear discriminant analysis) and advanced, but more computationally intensive, classifiers (autoencoders and convolutional neural networks). Moreover, the association between the level of motor impairment and classification accuracy was tested. Three channels of surface EMG were recorded during the following motion classes: Hand Close, Hand Open, Wrist Extension, Wrist Flexion, Supination, Pronation, Lateral Grasp, Pinch Grasp, and Rest. Six repetitions of each motion class were performed on two different days. Hudgins time‐domain features were extracted and classified using linear discriminant analysis and autoencoders, and raw EMG was classified with convolutional neural networks. On average, 79 ± 12% and 80 ± 12% (autoencoders) of the movements were correctly classified for days 1 and 2, respectively, with an intraclass correlation coefficient of 0.88. No association was found between the level of motor impairment and classification accuracy (Spearman correlation: 0.24). It was shown that nine motion classes could be decoded from residual EMG, with autoencoders being the best classification approach, and that the results were reliable across days; this may have implications for the development of EMG‐controlled exoskeletons for training in the patient’s home.

Description
Keywords
EMG , brain-computer interface , myoelectric control , pattern recognition , stroke , 46 Information and Computing Sciences , 4611 Machine Learning , Stroke , Neurosciences , Brain Disorders , Clinical Research , Bioengineering , Rehabilitation , Neurological , Stroke , 0301 Analytical Chemistry , 0502 Environmental Science and Management , 0602 Ecology , 0805 Distributed Computing , 0906 Electrical and Electronic Engineering , Analytical Chemistry , 3103 Ecology , 4008 Electrical engineering , 4009 Electronics, sensors and digital hardware , 4104 Environmental management , 4606 Distributed computing and systems software
Source
Sensors (Switzerland), ISSN: 1424-8220 (Print); 1424-8220 (Online), MDPI AG, 20(23), 1-14. doi: 10.3390/s20236763
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