The challenge of controlling an auditory BCI in the case of severe motor disability

Table 1 Experimental conditions for each patient

Patients	Set up	Number of electrodes	Lateralized stimulations (“yes” on the right, “no” on the left)	Calibration(S)				Test
				1st		2nd
				SOA (ms)	Number of blocks	SOA (ms)	Number of blocks	SOA (ms)	Number of blocks
LIS1	Vamp™	16	No^c	350	14	350	14	NA	NA
LIS2	Vamp™	16	Yes	350	14	350	14	NA	NA
LIS3	Vamp™	16	Yes	350	7^a	500	14	500	20
ALS1	BrainAmp™	32	Yes	300	14	NA	NA	300	30
ALS2	BrainAmp™	27^b	Yes	300	14	400	14	400	20
ALS3	BrainAmp™	32	Yes	400	14	NA	NA	400	30
ALS4	BrainAmp™	32	Yes	400	14	NA	NA	400	30

A calibration was usually based on 14 blocks and tests were repeated by bunchs of 10 blocks, but only if the patient was willing to pursue. The stimulus onset asynchrony (SOA) was adjusted if the patient told us that the stimulations were presented at too high a rate. We usually began with a SOA of 300 ms
NA not available. (see more explanations in the text)
^aShortened calibration because the patient told us it was going too fast
^bNo electrode at the back of the head because of huge artifacts
^cUnilateral stimulations because this patient was deaf in one ear (unilateral deafness that existed prior to the brainstem lesion). Hence this patient had the alternance of the “yes” and “no” in the same ear

ISSN: 1743-0003