Brain-Computer Interface Channel-Selection Strategy Based on Analysis of Event-Related Desynchronization Topography in Stroke Patients

Table 2

Channel-selection strategies and classification performance.

Group	Subject	SM1-4 selection	Accuracy	SM1-5 selection	Accuracy	ERD selection	Accuracy
ERD-blind group	4	None	None	None	None	None	None
	11	None	None	None	None	None	None
	14	None	None	None	None	None	None
Average ± SD			None		None		None
ERD-disappea-rance group	2	None	None	None	None	None	None
	15	None	None	None	None	None	None
Average ± SD			None		None		None
ERD-proliferation group	1	Cz C1 C3 C5	82.5%	C1 C3 C5 FC3 CP3	82.5%	CP1 Pz C1 TP8	92.5%
	3	Cz C1 C3 C5	67.5%	C1 C3 C5 FC3 CP3	67.5%	FC5 C4 C5 C1	80.0%
	6	Cz C1 C3 C5	60.0%	C1 C3 C5 FC3 CP3	62.5%	C4 CP2 AF8 C2	67.5%
	9	Cz C1 C3 C5	70.0%	C1 C3 C5 FC3 CP3	72.5%	C4 CP2 CP6 CP4	77.5%
Average ± SD			70.00 ± 9.35%		71.25 ± 8.54%		79.38 ± 10.28%
ERD-SM1 group	5	Cz C1 C3 C5	67.5%	C1 C3 C5 FC3 CP3	75.0%	C3 CP1 FC3 C1	75.0%
	7	Cz C1 C3 C5	72.5%	C1 C3 C5 FC3 CP3	72.5%	C1 C2 C3 C4	75.0%
	10	Cz C2 C4 C6	65.0%	C2 C4 C6 FC4 CP4	67.5%	C4 AF3 F5 CP4	70.0%
	12	Cz C1 C3 C5	65.0%	C1 C3 C5 FC3 CP3	65.0%	C3 FC3 C1 CP3	67.5%
Average ± SD			67.50 ± 3.54%		70.00 ± 4.56%		71.88 ± 3.75%
Others	8	Cz C1 C3 C5	85.0%	C1 C3 C5 FC3 CP3	85.0%	F7 FC2 C4 F5	87.5%
	13	Cz C1 C3 C5	60.0%	C1 C3 C5 FC3 CP3	62.5%	Cz CP1 C1 C2	65.0%
Average ± SD			72.50 ± 17.68%		73.75 ± 15.91%		76.25 ± 15.91%
Overall average ± SD			69.50 ± 8.48%		71.25 ± 7.84%		75.75 ± 8.98%

SM1-4 selection, 4 channels selected from the sensorimotor cortex. SM1-5 selection, 5 channels selected from the sensorimotor cortex. ERD selection, 4 channels selected with the lowest ERD ratio. SD, standard deviation.