Is the Conners’ continuous performance test helpful for assessing attention deficit hyperactivity disorder in a clinical setting?

Figures & data

Table 1. Sample characteristics.

	Children receiving an ADHD Diagnosis N = 46			Children not receiving an ADHD Diagnosis N = 23
	N	Mean	SD	N	Mean	SD	P
Age	46	9.8	3.1	23	10.0	2.4	0.163
ADHD-Rating Scale total mothers	44	30.1	10.9	22	25.1	11.0	0.097
ADHD-Rating Scale total teachers	42	31.1	11.0	22	17.8	10.5	0.000***
	N	%		N	%		P
Female	11	24		3	13		0.356
With comorbid disorder	20	44		7	30		0.433
>1 comorbid disorder	4	8.7		1	4.3		0.658

***p<.001 after Bonferrroni correction.

Table 2. Definitions of the parameters measured with the CCPT-II, modified after (17].

Omissions – errors occurring from the failure to respond to target letters (non-X’s)

Commissions - errors occurring when responses are given to non-targets (X’s)

Hit reaction time - overall (Hit RT) - the average speed in milliseconds of correct responses for the entire test over all six blocks. High T -scores reflect fast response times

Hit RT Standard Error – overall (Hit RT Std Error) - a measure of response speed consistency; higher values relate to greater inconsistency

Variability of standard error – the amount of variability the individual shows in 18 separate segments of the test in relation to his or her own overall standard error. The higher variability of standard error, the greater the inconsistency of the response speed

Detectability (d’) - a measure of the difference between the signal (non-X) and noise (X) distributions. d’ provides information about an individual’s ability to discriminate between targets and non-targets

Response Style indicator (beta) - differs between cautious individuals, those more seldom responding than most other individuals, and those more freely responding

Hit RT Block Change - measures change in reaction time during the test; high values indicate slowing in reaction times whereas low values indicate fastening reaction times as the test is progressing

Hit SE Block Change - changes in response consistency over the duration of the test. High values indicate a loss of consistency as the test progresses, while low values indicate improved consistency

Hit RT ISI Change – measures change in average reaction time at the different inter stimulus intervals (ISI), in the test there are 1, 2 or 4 seconds intervals

Hit SE ISI Change – measures change in the standard error of reaction times at the different Inter Stimulus Intervals (ISI). High values indicated that the response time became less consistent with increasing intervals, higher consistency at increasing intervals gave lower values

Overall Index – is a weighted sum of the measures listed above

The measure of Perseverations - slow responses, random responses, or repeated responses given without considering the forgoing stimulus or task requirement (was let out because only a few of the individual responses in our sample could be analysed)

Table 3. Unadjusted Spearman Rho correlations between mothers’ and teachers’ ADHD rating scales scores and CCPT-II parameters (n = 69).

ADHD-RS scores	CCPT-II Omissions	CCPT-II Commissions	CCPT-II Hit Reaction time	CCPT-II Variability	CCPT-II Detectability	CCPT-II Response style	CCPT-II Hit RT Block Change	CCPT-II Hit RT ISI Change	CCPT-II Hit RT ISI Change - SE	CCPT-II Overall Index
Inattention:
Mothers	.094	.083	−.069	.028	−.003	.042	.166	.129	−.044	.178
Teachers	.096	.382**	−.256	.004	−.155	.129	−.224	.157	.090	.124
Hyperactivity/Impulsivity:
Mothers	.285*	−.104	.414***	.400**	.082	.094	.271*	.264*	.217	.263*
Teachers	.151	.280*	.038	.265*	−.201	.169	−.123	.224	.246	.049
Total score:
Mothers	.218	.010	.182	.249	.033	.086	.260*	.264*	.217	.263*
Teachers	.159	.371**	−.128	.164	−.191	.129	−.224	.157	.090	.126

*p < 0.05, **p < 0.01, ***p < 0.001.

Table 4. Uncorrected differences between children with or without ADHD diagnosis and children’s CCPT-II performance.

	Children receiving an ADHD Diagnosis			Children not receiving an ADHD Diagnosis
	N	Mean	SD	N	Mean	SD	t-value	p
CCPT-II Omissions	40	21.4	20.4	22	14.2	14.0	1.641	0.106
CCPT-II Commissions	40	27.0	6.2	22	23.1	6.6	2.196	0.032*^a
CCPT-II Hit RT	40	400.1	105.9	22	425.8	75.1	1.104	0.272
CCPT-II Variability	40	29.3	24.3	22	24.7	20.3	0.792	0.431
CCPT-II Detectability	40	0.7	0.7	22	1.1	0.9	1.983	0.052
CCPT-II Block Change	40	0.0	0.0	22	0.0	0.1	1.646	0.105
CCPT-II Hit RT ISI Change	40	0.1	0.1	22	0.1	0.1	1.974	0.053

^aafter Bonferroni correction not significant.

Table 5. Diagnostic consensus between Kiddie-SADS rating and final diagnosis of ADHD (N = 69).

Final conclusion ADHD yes 46 (66.7 %) / Final conclusion ADHD no 23 (33.3 %)	Frequency (%)
Agreed ADHD yes, in Kiddie-SADS and in final conclusion	38 (55.1 %)
Agreed ADHD no, in Kiddie-SADS and in final conclusion	15 (21.7 %)
Disagreed ADHD yes in Kiddie-SADS, but ADHD no in final conclusion	8 (11.6 %)
Disagreed ADHD no in Kiddie-SADS, but ADHD yes in final conclusion	8 (11.6 %)

Conners CK. 2000. Conners’ continuous performance test II: computer program for windows technical guide and software manual. North Tonwanda, NY: Mutli-Health Systems.

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