A Robust and Self-Paced BCI System Based on a Four Class SSVEP Paradigm: Algorithms and Protocols for a High-Transfer-Rate Direct Brain Communication

Table 1

Results using the CSP method for automatic spatial filtering as described in Section 2.2.2. Error rate, typical delay time, and bit-rate calculated on the basis of the testing session performed by each subject of group G1 and G2 using different data analysis window lengths. For each group, the average values across subject are presented (MEAN). A global results calculated on every subject from both control groups is also provided (G1 + G2).

	ID	Data window length
		2 seconds			3 seconds			4 seconds
		ERR  [%]	DLY  [sec]	BR  [bit/min]	ERR  [%]	DLY  [sec]	BR [bit/min]	ERR  [%]	DLY  [sec]	BR  [bit/min]
G1	S11	0.57	2.25	51.83	0.00	2.84	42.26	0.00	3.29	36.53
	S12	0.62	1.68	69.31	0.00	2.30	52.16	0.62	2.58	44.98
	S13	7.03	5.39	16.93	6.83	11.33	8.11	6.21	11.93	7.88
	S14	0.00	3.25	36.88	0.00	3.63	33.07	0.00	3.97	30.21
	S15	3.01	2.49	42.37	0.00	3.18	37.79	0.00	3.66	32.79
	S16	2.26	1.77	61.32	0.00	2.33	51.46	0.00	2.85	42.14
	S17	4.97	1.71	57.24	4.42	2.46	40.62	2.76	3.02	35.25
	MEAN	2.64	2.65	47.98	1.61	4.01	37.92	1.37	4.47	32.82
G2	S21	0.00	1.77	67.81	0.00	2.18	55.15	0.00	2.55	47.04
	S22	5.42	2.05	47.10	3.01	2.71	38.95	4.82	3.21	30.78
	S23	1.18	1.89	59.81	0.59	2.49	46.74	0.00	2.94	40.80
	S24	2.40	1.94	55.60	0.00	2.38	50.44	0.00	2.93	41.01
	MEAN	2.25	1.91	57.58	0.90	2.44	47.82	1.20	2.91	39.91
	G1 + G2	2.50	2.38	51.47	1.35	3.44	41.52	1.31	3.90	35.40