Age-related change in the difference between left-and right-side speed on motor examination may be an important indicator of maturation. Cortical maturation and myelination of the corpus callosum are considered to be related to increased bilateral skill and speed on timed motor tasks. We compared left minus right foot, hand, and finger speed differences using the Revised Physical and Neurological Assessment for Subtle Signs (PANESS; Denckla, 1985); examining 130 typically developing righthanded children (65 boys, 65 girls) ages 7−14. Timed tasks included right and left sets of 20 toe taps, 10 toe-heel alternation sequences, 20 hand pats, 10 hand pronate-supinate sets, 20 finger taps, and 5 sequences of each finger-to-thumb apposition. For each individual, six difference scores between left-and right-sided speeded performances of timed motor tasks were analyzed. Left-right differences decreased significantly with age on toe tapping, heel-toe alternations, hand pronation-supination, finger repetition, and finger sequencing. There were significant gender effects for heel-toe sequences (boys showing a greater left-right difference than girls), and a significant interaction between age and gender for hand pronation-supination, such that the magnitude of the left-right difference was similar for younger, compared with older girls, while the difference was significantly larger for younger, compared to older boys. Speed of performing right and left timed motor tasks equalizes with development; for some tasks, the equalization occurs earlier in girls than in boys. KeywordsMotor; PANESS; Laterality; Gender; Corpus callosumThe majority of studies examining motor development in children suggests that hand preference emerges for a variety of skills between ages 3 and 6 years. By Kindergarten, most typically developing children consistently demonstrate a clear hand preference, with approximately 90% showing right-hand preference for most activities (Best, 1988;Oeztuerk et al., 1999;. The remaining 10% of Kindergarten children show either left-or mixed-hand preference, or delayed manifestation of handedness, suggesting age-related changes that may continue throughout the school-age years. Hand preference implies that the preferred hand is more proficient than the nonpreferred hand in terms of coordination and speed. During the first five years of life, the preferred hand begins to emerge as superior to the nonpreferred hand in terms of speed and coordination. Typically developing toddlers demonstrate an increasingly lateralized hand preference for activities such as reaching, manipulation of toys, and drawing, with more children at age 2 years showing consistent hand preference than those at 9 and 13 months of age, particularly on crayon tasks (Cornwell, Harris, & Fitzgerald, 1991). After age 5 years, however, although hand preference persists, these lateral differences diminish; this is likely to be due (at least in part) to the rapid development and myelination of the corpus callosum that allows for more efficient co...

Children with attention deficit hyperactivity disorder (ADHD) often show poor performance on tasks that require strategic planning. To assess this ability, we developed a paper and pencil task that required consistent use of a simple test-taking strategy to maximize the number of points. The visual discrimination task with minimal cognitive demands required children to maximize their gains by responding only to outlined high-point problems and to skip the low-point problems. The task was administered twice, the second time with explicit instructions on how to implement the strategy. Few of the children in the ADHD or control group, ages 8-13 years, were able to discover the strategy on their own, but after explicit instruction 90% of the children in the control group but only 57.5% of children with ADHD used the strategy to maximize points (p < .005). The ADHD group used the strategy less efficiently, despite the fact that they did not differ on the total number of problems completed. The findings suggest that children with ADHD have impaired ability to implement strategic approaches for tasks similar to school assignments. The task can potentially be developed as a diagnostic aid and as a basis for further research assessing strategic planning in ADHD.

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