Analysis 1: gender effects
In general, children with high scores on the Disruptive Behavior Disorders (DBD) rating scales, who were classified as having ADHD symptoms, performed more poorly on the Grooved Pegboard and Motor Coordination Task than the comparison group without ADHD symptoms. Further, girls performed worse than boys. There were no differences in performance on the Finger Tapping Test.
Figures 1A, 2A and 3A present the performances for each of the three tasks for both hands for the subtypes with ADHD symptoms and the non-ADHD comparison group for both genders. Figure 1A shows that the children with ADHD symptoms took more time than the comparisons to finish the task. This was the case for both the dominant and the non-dominant hand. Generally, the girls took longer to complete the task than the boys. This was however not the case for the group with Predominantly Inattentive symptoms (ADHD-PI). Figure 2A illustrates that the children with ADHD symptoms touched the side of the maze more often than the comparison group. The girls had overall more touches than the boys. This was the case with both hands. Figure 3A shows that there were no obvious differences in performance between the children with symptoms of the ADHD subtypes and the non-ADHD comparisons. There is also no obvious difference in performance between the genders.
The statistical results are shown in Table 2. For the Grooved Pegboard and the Maze Coordination Task there were statistically significant main effects of ADHD subtype and gender (ps
Post-hoc testing (with Bonferroni correction) of the Grooved Pegboard and the Maze Coordination Task showed that in both tests, the children with symptoms of the ADHD-C subtype had the poorest performance. The differences, when compared with the non-ADHD group, were statistically significant for both genders. Both girls and boys with symptoms of the ADHD-PI subtype performed significantly poorer than the comparison group only in the Maze Coordination Task with the dominant hand. This was the case for both genders. When girls with ADHD-HI symptoms used their dominant hand, they performed significantly worse than the boys on the Grooved Pegboard as well as the Maze Coordination Task.
Analysis 2: age effects
Figures 1B, 2B and 3B present the performances for all three tasks for both hands for the children with symptoms of the ADHD subtypes and the non-ADHD comparison group for the age groups 6 – 9 yr and 10 – 13 yr. As could be expected, the younger group's performance was consistently poorer than the older group on all three tasks. Figure 1B shows that it was especially the children with symptoms of ADHD-C and ADHD-HI that encountered the most difficulties on the Grooved Pegboard. This was the case for both age groups for both hands. Figure 2B shows that on the Maze Coordination Task the children with symptoms of the ADHD subtypes' performance were poorer than that of the non-ADHD comparison group. This was true for both the dominant- and the non-dominant hand. The results were more pronounced in the younger group. Figure 3B illustrates that in both age groups there was little difference in finger tapping performance between the group with symptoms of the ADHD subtypes and the non-ADHD comparisons.
The effects of ADHD subtype symptoms, gender and age for all three tests are shown in Table 2. There were statistically significant main effects of symptoms of ADHD subtype (ps
Bonferroni corrected post-hoc tests on the Grooved Pegboard and the Maze Coordination Task showed that again, that the groups with symptoms of the ADHD-C subtype had the poorest performance. This was however, only in the case in the younger group. No significant effect was found in the difference between the older children with symptoms of ADHD-C and their non-ADHD comparisons. Independent of hand used, the younger children with symptoms of ADHD-HI differed significantly from the comparisons in the Grooved Pegboard, but not in the Maze Coordination Task. Similarly, independent of hand used, the younger children with ADHD-PI symptoms differed significantly from the comparisons on the Maze Coordination Task, but only with the non-dominant hand on the Grooved Pegboard. The older group (10 – 13) did not differ significantly, from the non-ADHD comparisons in any of the tasks.