Abstract
Introduction: Manual dexterity requires that the head and body are stable so that vision can be used to generate movement and correct errors. Manual dexterity and postural control improve with age so the development of manual skill must involve changes in the relationship between head, body and hand. Nevertheless, this relationship has not been well investigated whilst participants undertake a manual task, probably because of the technical difficulties in simultaneous recording. Methods: We created a system capable of presenting visuomotor tasks whilst objectively measuring manual skill, head movements and postural sway. We explored performance in four conditions: (i) Stationary fixation; (ii) Eyes closed; (iii) Visual tracking of moving targets at slow, medium and fast speeds; (iv) Tracking the moving targets with a handheld stylus. 514 children were recruited aged 3-11 years. The strengths and difficulties questionnaire provided an index of autistic traits and these data were combined with a range of educational measures. Results: A relationship was found between postural sway with stationary fixation and manual dexterity performance. Adults were able to visually track the moving target with minimal head movements and postural sway. The younger children showed large head movements with associated postural adjustments. A clear trend towards adult behaviour was observed as a function of age. These effects were magnified when children tracked the moving target with the handheld stylus. A composite ‘ASD trait’ score was found to significantly correlate with manual dexterity, postural stability, and head movement. Conclusions: These results suggest our system has potential as a population level tool for objectively measuring posture and detecting developmental disorders. These results will be discussed with regard to ongoing data collection in a cohort of 13,500 children (Born in Bradford) where performance on our task can be related to genetic, health and educational data on the children and parents.
Meeting abstract presented at VSS 2013