Objective and Subjective Evaluation of Online Error Correction during P300-Based Spelling

Table 1

Individual and group performance in spelling, error detection, and correction. The first three columns indicate the subject number and demographical information such as gender and age. The next two columns indicate the spelling accuracy (percent of correct letters) for the whole five sessions (mixing words spelled with 2 and 4 sequences) and for the fifth session alone (the one dedicated to online evaluation of error correction, without considering the online correction), respectively. The next four columns indicate the individual sensitivity, specificity, 𝜃, and gain in spelling accuracy obtained in the last session, reported in percent. The last four columns show the individual responses to the most relevant questions (see Table 2 for a full description). The last three lines provide results at the group level (first line) and after having distinguished between low specificity (second line) and high specificity (third line) performers.

Subjects	Dem. info.		Spelling accuracy		ErrP detection		Correction		Questionnaire
	Sex	Age (year)	Sessions 1 to 5	Session 5 only	Sens.	Spec.	𝜃	Gain	Q1	Q2	Q8	Did you prefer with or without correction?
1	m	34	82%	80%	35%	69%	47%	−19%	5	5	2	without
3	m	25	32%	25%	72%	68%	25%	1%	1	1	2	without
4	f	31	44%	36%	75%	69%	24%	−2%	6	5	1	without
6	f	20	42%	31%	81%	61%	23%	0%	4	8	8	with
12	m	23	66%	56%	48%	70%	39%	−9%	7	6	4	without
14	f	23	52%	50%	70%	72%	35%	−1%	4	6	5	without
2	f	32	65%	56%	68%	93%	39%	7%	5	7	6	with
5	m	28	70%	72%	46%	96%	46%	3%	7	7	5	with
7	f	37	93%	89%	27%	97%	44%	−3%	8	8	1	without
8	f	29	90%	87%	62%	97%	59%	0%	5	7	2	without
9	f	26	72%	65%	69%	88%	41%	1%	6	7	7	with
10	f	22	84%	79%	90%	99%	58%	12%	7	8	7	without
11	m	26	91%	88%	25%	95%	61%	−2%	8	8	4	without
13	m	23	55%	41%	59%	90%	40%	11%	5	6	9	with
15	m	27	63%	50%	34%	94%	45%	6%	7	8	8	with
16	f	25	94%	91%	67%	99%	50%	3%	8	8	9	with
	Summary	Metasubject										Summary
All	7 m; 9 f	26.9	69%	62%	63%	88%	36%	1%	5.8	6.6	5.0	44% with
Spec < 0.75	3 m; 3 f	26	53%	46%	69%	69%	29%	−5%	4.5	5.2	3.7	17% with
Spec > 0.85	4 m; 6 f	27.5	78%	72%	56%	95%	45%	4%	6.6	7.4	5.8	60% with