Continuous performance task in ADHD: Is reaction time variability a key measure?

Figures & data

Table 1 Participant characteristics for children in the X-task and A-X-task cohorts

Characteristics	X-task	A-X-task
Age in months, range (mean ± SD)	42–196, (94.3±26.9)	88–167, (120.7±21.7)
Gender, N (%)
Male	651 (79.8)	60 (100)
Female	164 (20.1)
Handedness, N (%)
Right	627 (77.0)	60 (100)
Left	108 (13.3)	–
Other	79 (9.7%)	–

Note: ‘–’ indicates not measured.

Table 2 Mean RT, RTV, and CV for children with low, medium and high severity of ADHD in the X-task clinical cohort

ADHD severity	Mean	SD	N
Mean RT (ms)
Low ADHD	766	199	324
Med ADHD	808	229	273
High ADHD	844	216	200
RTV (ms)
Low ADHD	54,025	67,084	323
Med ADHD	79,630	91,685	273
High ADHD	89,100	83,207	198
CV
Low ADHD	0.2587	0.1196	324
Med ADHD	0.2882	0.1097	274
High ADHD	0.3049	0.1250	200

Abbreviations: ADHD, attention-deficit hyperactivity disorder; CV, coefficient of variation; RT, reaction time; RTV, reaction time variability.

Table 3 Mean RT, RTV, and CV for children with low, medium, and high level of ADHD in the A-X-task cohort

ADHD level	Mean	SD	N
Mean RT (ms)
Low ADHD	545	166	18
Med ADHD	604	116	20
High ADHD	560	143	19
RTV (ms)
Low ADHD	42,988	46,486	18
Med ADHD	58,874	47,602	20
High ADHD	41,298	38,189	19
CV
Low ADHD	0.3132	0.1259	18
Med ADHD	0.3645	0.1404	20
High ADHD	0.3323	0.1025	19

Abbreviations: ADHD, attention-deficit hyperactivity disorder; CV, coefficient of variation; RT, reaction time; RTV, reaction time variability.

Table 4 Mean RT, RTV, and CV for children with and without medication in the X-task and A-X-task cohorts

Tasks	No medication		With medication		N
	Mean	SD	Mean	SD
X-task
Mean RT (ms)	769	190	751	232	25
RTV (ms)	51,732	57,151	38,318	34,009	25
CV	0.4874	0.1702	0.2355	0.0708	25
A-X-task
Mean RT (ms)	566	142	570	142	60
RTV (ms)	46,876	43,687	55,354	56,620	60
CV	0.3351	0.1220	0.3517	0.1570	60

Abbreviations: CV, coefficient of variation; RT, reaction time; RTV, reaction time variability.