Unimanual and bimanual continuous movements benefit from visual instructions in persons with Down syndrome.
ABSTRACT The authors' aim was to understand how persons with Down syndrome (DS) perform different tasks and to assess if there were any differences in performance based on the type of instructions. This is important because of neurological differences in persons with DS and neurological demands for performing different types of tasks. Twenty right-handed participants with DS, 20 chronological age-matched (CA), and 20 mental age-matched (MA) performed unimanual, bimanual, discrete, and continuous drumming following visual, auditory, and verbal instructions. Overall, discrete drumming was performed with shorter movement times than continuous drumming and unimanual drumming was performed with shorter movement amplitude than bimanual drumming. With respect to instructions, persons with DS performed with smaller amplitudes, thus more efficient movements, following the visual instructions than auditory and verbal instructions for all types of tasks, whereas CA performed similarly with all instructions and MA performed with smaller amplitudes with visual instructions than auditory instructions. These results suggest that visual instruction provides the best information for people with DS to aid in performance of many different types of movements.
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ABSTRACT: Laterality (hand, foot, ear, and eye) was assessed in participants with Trisomy 21 (62) and Williams-Beuren syndrome (WBS) (39). Handedness was also assessed in a card reaching task. The comparison group included 184 typically developing persons. Two independent age sub-groups were formed: 7 to 10 years old and 11 to 34 years old. We confirmed previous data: individuals with T21 were more frequently left- or mixed-handed than typically developing persons; individuals with WBS had intermediate scores. The two groups with genetic disorders had less right foot preference. Manual and foot inconsistencies characterized both groups with genetic disorders. Cross hand-foot preference was lower in the typically developing group. Differences in IQ levels did not correlate with differences in laterality scores. Overall laterality profiles were not the same in the two groups with genetic disorders: the greatest differences were observed between typically developing persons and persons with Trisomy 21.Developmental Psychobiology 09/2006; 48(6):482-91. DOI:10.1002/dev.20163 · 3.16 Impact Factor
Brain Research Bulletin 11/1999; 50(5). DOI:10.1016/S0361-9230(99)00174-4 · 2.97 Impact Factor
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ABSTRACT: To investigate functional differences between the rostral and caudal parts of the dorsal premotor cortex (PMd), we first examined the effects of intracortical microstimulation (ICMS) while monkeys were performing oculomotor and limb motor tasks or while they were at rest. We found that saccades were evoked from the rostral part (PMdr) whereas ICMS in the caudal part (PMdc) predominantly produced forelimb or body movements. Subsequently, we examined neuronal activity in relation to the performance of visually cued and memorized saccades while monkeys reached an arm toward a visual target. We found that roughly equal numbers of PMdr neurons were active during performance of the oculomotor and limb motor tasks. In contrast, the majority of PMdc neurons were related preferentially to arm movements and not to saccades. In the subsequent analysis, we found that the oculomotor effects evoked in the PMdr differ from the effects evoked in either the frontal eye field (FEF) or supplementary eye field (SEF). These findings suggest that the PMdr is involved in oculomotor as well as limb motor behavior. However, the oculomotor involvement of the PMdr seems to have a functional aspect different from that operating in the FEF and SEF.Journal of Neurophysiology 04/2000; 83(3):1764-9. · 3.04 Impact Factor