title: Reduced asymmetry in motor skill learning in left-handed compared to right-handed individuals.
abstract: Hemispheric specialization for motor control influences how individuals perform and adapt to goal-directed movements. In contrast to adaptation, motor skill learning involves a process wherein one learns to synthesize novel movement capabilities in absence of perturbation such that they are performed with greater accuracy, consistency and efficiency. Here, we investigated manual asymmetry in acquisition and retention of a complex motor skill that requires speed and accuracy for optimal performance in right-handed and left-handed individuals. We further determined if degree of handedness influences motor skill learning. Ten right-handed (RH) and 10 left-handed (LH) adults practiced two distinct motor skills with their dominant or nondominant arms during separate sessions two-four weeks apart. Learning was quantified by changes in the speed-accuracy tradeoff function measured at baseline and one-day retention. Manual asymmetry was evident in the RH group but not the LH group. RH group demonstrated significantly greater skill improvement for their dominant-right hand than their nondominant-left hand. In contrast, for the LH group, both dominant and nondominant hands demonstrated comparable learning. Less strongly-LH individuals (lower EHI scores) exhibited more learning of their dominant hand. These results suggest that while hemispheric specialization influences motor skill learning, these effects may be influenced by handedness.
authors.affiliation: Neuroplasticity and Motor Behavior Laboratory, Moss Rehabilitation Research Institute, Elkins Park, PA, United States.
authors.forename: Robert L
authors.initials: RL
authors.lastname: McGrath
authors.affiliation: Neuroplasticity and Motor Behavior Laboratory, Moss Rehabilitation Research Institute, Elkins Park, PA, United States; Department of Physical Therapy, Arcadia University, Glenside, PA, United States.
authors.forename: Shailesh S
authors.initials: SS
authors.lastname: Kantak
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D011214:Practice, Psychological; D011597:Psychomotor Performance; D011930:Reaction Time; D012153:Retention, Psychology
keywords: Goal-directed movements; Hemispheric specialization; Manual asymmetry