A Survey of Stimulation Methods Used in SSVEP-Based BCIs

Table 2

Characteristics of single graphic stimuli.

Frequency band	Study	Stimulus				Bit rate (bits/min)
		Device	Shape	Frequency (Hz)	Color
L	Wang et al. 2008 [7]	—	Square	10 Hz	—	—
	Ren et al. 2008 [40]	—	Square	10 Hz	White/black	—
	Touyama and Hirose, 2007 [41]	—	Cube	4.80, 6.86 Hz	—	—
	Touyama and Hirose, 2007 [42]	—	Cube	4.80, 6.86 Hz	—	—
	Beverina et al. 2003 [14]	—	Arrow	6, 10 Hz	Green	—
	Cheng and Gao, 1999 [13]	—	Block	6–9 Hz	—	—
M	Cecotti and Graeser, 2008 [43]	LCD	Box	15.5, 16, …, 17.5 Hz	—	—
	Kelly et al. 2005 [44]	CRT	Rectangle	14, 17 Hz	White/black	7.5
L+M	Bin et al. 2009 [45]	LCD	Square	6.5, 7.5, 8.6, 10, 12, 15 Hz	White/black	58
	Wu et al. 2008 [9]	LCD and CRT	Square	4.6, 10.8, 16.1 Hz	White/black	—
	Wang et al. 2006 [46]	CRT	Button	9–17 Hz	—	43
	Nielsen et al. 2006 [47]	CRT	Square	5.0, 7.08, 7.73, 8.5, 9.44, 10.63, 12.14, 14.16, 17.0 Hz	—	21
	Kelly et al. 2005 [48]	CRT	Rectangle	9.45, 10.63 Hz; 14.17, 17.01 Hz	White/black	—
	Kelly et al. 2005 [49]	CRT	Rectangle	10.03, 12.04 Hz	White/black	—
	Wahnoun et al. 2002 [50]	—	Block	5.000, 7.080, 7.727, 8.927, 11.087, 12.140, 12.750, 17.000, 21.250 Hz	White and a small light gray in the middle	—
	Cheng et al. 2002 [51]	CRT	Button	6–14 Hz	—	27.15
	Cheng et al. 2001 [18]	—	Block	6.45, 7.23, 8.01, 13.87 Hz	Red, green, and yellow	—
L+H	Sami and Nielsen, 2004 [52]	CRT	Rectangle	8.8, 35 Hz	—	—
M+H	Lin et al. 2007 [53]	CRT	Squares	27,  29, …, 43 Hz	—	—