Disentangling the relationships between motor control and cognitive control in young children with symptoms of ADHD

Figures & data

Table 1. Descriptive statistics for the main sample and the cognitive modelling subsample.

	Main sample (N = 255)		Cognitive modelling subsample (n = 150)
	Mean (SD)	Median (MAD)	Mean (SD)	Median (MAD)
Contextual variables
Age (years)	6.5 (1.1)	6.50 (1.4)	6.6 (0.9)	6.6 (1.1)
IQ (estimated) Anxiety Low mood Coordination	98.3 (12.0) 63.4 (12.2) 62.8 (9.9) 45.5 (13.3)	98.0 (11.9) 62.0 (15.6) 60.0 (11.9) 45.0 (14.8)	99.9 (12.0) 62.8 (11.5) 62.4 (9.7) 46.6 (13.4)	99.0 (13.3) 61.0 (13.3) 60.0 (11.9) 47.0 (13.3)
ADHD Symptoms
Hyperactive-Impulsive	11.0 (6.7)	13.0 (6.2)	10.8 (6.0)	13.0 (5.9)
Inattentive	10.8 (6.0)	12.0 (5.9)	10.5 (5.9)	11.0 (5.9)
Motor control tasks
Tapping (motor generation)	−1.0 (1.7)	−0.39 (1.1)	−1.2 (1.8)	−0.6 (1.4)
Tracking (visuomotor fluency)	−2.4 (3.3)	−1.40 (2.1)	−2.1 (2.7)	−1.3 (1.9)
Pursuit (visuomotor flexibility)	−2.1 (5.4)	−0.30 (1.7)	−1.5 (3.4)	−0.5 (1.5)
Cognitive control tasks
Flanker (cognitive inhibition)	93.0 (14.9)	94.0 (11.9)	99.1 (11.1)	100.0 (14.8)
DCCS (cognitive flexibility)	95.5 (14.1)	96.0 (10.4)	95.6 (14.2)	97.5 (8.2)
BDR (verbal working memory)	98.7 (16.5)	98.0 (16.3)	101 (16.5)	100 (14.8)
Mr X (visuospatial working memory)	106.1 (17.2)	104.0 (17.8)	111 (17.0)	111 (14.8)
Mr X Processing (working memory manipulation)	103.8 (16.6)	99.0 (13.3)	108 (17.0)	104 (17.8)
Cognitive modelling parameter estimates
Drift rate (processing efficiency)	-	-	0.14 (0.0)	0.14 (0.0)
Boundary separation (speed-accuracy trade-off)	-	-	0.22 (0.0)	0.23 (0.0)
Nondecision time (stimuli encoding and motor execution)	-	-	0.73 (0.3)	0.70 (0.3)

Note: Statistics are based on untransformed data. Anxiety and low mood data are T scores from the Child Behaviour Checklist, with higher scores representing greater severity (Achenbach & Rescorla, 2000). Coordination data reflect total score on the Developmental Coordination Disorder Questionnaire (Wilson et al., 2009). ADHD symptoms reflect raw scores from the DAWBA. Motor control task data are z scores. Cognitive control task data are standardise scores with a mean of 100 and a standard deviation of 15. ADHD: Attention Deficit Hyperactivity Disorder. BDR: Backwards Digit Recall. DCCS: Dimensional Change Card Sort Task. IQ: Overall cognitive ability estimated with the Lucid Ability Test. MAD: Median absolute deviation. Mr X: Mister X. SD: Standard deviation.

Table 2. Correlations amongst transformed variables.

	Background variables		Motor control tasks			Sx	Cognitive control tasks
	Age	IQ	TP	TR	PU	HI	FL	DC	BD	MX
IQ	−.11
TP	−.11	.14
TR	.27	.23	.24 (.21)
PU	.33	.27	.13 (.01)	.52 (.51)
HI	.26	.07	−.01	.13	.11
FL	.05	.26	.00	.23	.27	.12
DC	−.07	.44	.12	.14	.19	.08	.35 (.32)
BD	−.10	.37	.11	.10	.21	.00	.14 (.03)	.30 (.25)
MX	−.08	.24	.05	.00	.08	.37	.08 (.05)	.11 (.00)	.31 (.06)
MP	−.08	.24	.03	.06	.10	.36	.06 (.04)	.11 (.00)	.22 (.13)	.83 (.82)

Note: Correlations outside of brackets are bivariate, correlations within brackets are partial correlations controlling for other variables in their category (e.g., other motor control tasks). Correlations in bold are significant at the 0.05 level. ADHD: Attention Deficit Hyperactivity Disorder. BD: Backwards Digit Recall (verbal working memory). DC: Dimensional Change Card Sort (cognitive flexibility). FL: Flanker (cognitive inhibition). HI: Hyperactive-Impulsive Symptoms. IQ: Lucid Ability Test (overall cognitive ability). MX: Mister X (visuospatial working memory). MX P: Mister X Processing (visuospatial working memory manipulation). PU: Pursuit (visuomotor flexibility). Sx: Symptoms. TP: Tapping (motor generation). TR: Tracking (visuomotor fluency).

Table 3. Multiple linear regression analyses of motor control and cognitive control tasks.

Hyp.	Dependent and predictor variables	Adj. R^2	β	SE	t	p
A1	Flanker (cognitive inhibition) Intercept Tapping (motor generation) Tracking (visuomotor fluency) Hyperactive-Impulsive Sx Tapping * Hyperactive-Impulsive Sx	0.05	−0.00 −0.07 0.21 0.10 0.08	0.06 0.07 0.06 0.06 0.07	−0.01 −1.07 3.32 1.52 1.05	.002 .99 .29 .001 .13 .29
A2	Backwards Digit Recall (verbal working memory) Intercept Tapping (motor generation) Hyperactive-Impulsive Sx Tapping * Hyperactive-Impulsive Sx	0.01	0.00 0.08 0.01 0.12	0.06 0.07 0.06 0.07	0.04 1.17 0.13 1.61	.13 .96 .24 .90 .11
A2	Mister X (visuospatial working memory) Intercept Tapping (motor generation) Hyperactive-Impulsive Sx Tapping * Hyperactive-Impulsive Sx	0.13	−0.00 0.07 0.38 −0.05	0.06 0.06 0.06 0.07	−0.03 1.06 6.34 −0.74	< .001 .98 .29 < .001 .46
A3	Mister X Processing (working memory manipulation) Intercept Tracking (visuomotor fluency) Pursuit (visuomotor flexibility) Hyperactive-Impulsive Sx Tracking * Hyperactive-Impulsive Sx Pursuit * Hyperactive-Impulsive Sx	0.12	−0.02 −0.04 0.06 0.36 0.08 0.05	0.06 0.07 0.07 0.06 0.08 0.08	−0.28 −0.57 0.86 5.87 0.96 0.61	< .001 .78 .57 .39 < .001 .34 .54
A4	Dimensional Change Card Sort (cognitive flexibility) Intercept Tapping (motor generation) Tracking (visuomotor fluency) Pursuit (visuomotor flexibility) Hyperactive-Impulsive Sx Tapping * Hyperactive-Impulsive Sx	0.03	0.00 0.09 0.04 0.15 0.06 −0.01	0.06 0.07 0.07 0.07 0.06 0.08	0.01 1.38 0.48 2.09 0.94 −0.13	.029 .99 .17 .63 .037 .35 .90

Note: Bold text denotes statistically significant results. The alpha level was 0.05 for each model. Hyp: Relevant hypothesis. Sx: Symptoms.

Table 4. Multiple linear regression analyses of motor control and cognitive modelling variables.

Hyp.	Dependent and predictor variables	Adj. R^2	Est.	SE	t	p
B1	Drift rate (processing efficiency)	0.00				.39
	Intercept		0.00	0.08	−0.04	.97
	Tapping (motor generation)		−0.06	0.08	−0.75	.46
	Tracking (visuomotor fluency)		0.16	0.08	1.88	.06
	Hyperactive-Impulsive Sx		−0.05	0.08	−0.55	.58
	Tapping * Hyperactive-Impulsive Sx		−0.06	0.11	−0.55	.59
	Tracking * Hyperactive-Impulsive Sx		0.09	0.09	0.96	.34
B2	Boundary separation (speed-accuracy trade-off) Intercept	0.00	0.00	0.08	0.00	.51 1
	Tracking (visuomotor fluency)		−0.11	0.08	−1.33	0.18
	Hyperactive-Impulsive Sx		−0.06	0.08	−0.75	0.45
	Tracking * Hyperactive-Impulsive Sx		−0.02	0.09	−0.18	0.86
B3	Nondecision time (stimuli encoding and motor response execution)	0.01				.17
	Intercept		−0.02	0.08	−0.19	.85
	Tapping (motor generation)		0.11	0.08	1.33	.18
	Hyperactive-Impulsive Sx		−0.09	0.08	−1.12	.26
	Tapping * Hyperactive-Impulsive Sx		−0.16	0.10	−1.58	.12

Note: The alpha level was set at 0.05. Hyp: Hypothesis. Sx: Symptoms.

Achenbach, T. M., & Rescorla, L. A. (2000). Manual for the ASEBA preschool forms and profiles. University of Vermont Department of Psychiatry.

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