Increasing right hand dominance with age on a motor skill task.

A standardized pegboard task was used to investigate changes in manipulative skill as a function of age in 119 right-handed subjects. The typical pattern of cognitive impairment in old age indicates a relative preservation of functions which depend on the integrity of the left hemisphere. In accord with these observations, we predicted that, with increasing age, right hand motor skills would be better preserved than left hand skills. We found this on initial exposure to the task (P less than 0.01); however, the phenomenon was masked by practice, because older subjects (over 60 years of age) derived more improvement to their left hand motor skill, as a result of practice, than they did to their right hand skill (P less than 0.05). The asymmetrical effects of ageing on motor skill may be relevant to the increasing prevalence of emotional lability and neurosis in the elderly, since emotional control is thought to be dependent on right hemisphere mechanisms.