Assessing manual wheelchair caster design for mobility in winter conditions.

Wheelchair users who live in cold climates are faced with daily difficulties related to personal independence and societal inclusion as their assistive devices are unable to overcome the physical barriers created by snow and ice. The purpose of the research was to evaluate four commercially available casters to determine which caster performed best on snow-covered surfaces. Performance measures included: travel time, force transfer through the palms of the hands, number of propulsive movements, static resistance to movement, kinetic resistance to movement, and caster penetration into the packed snow. On a snow-covered incline, the FreeWheel™ caster enabled travel time to be decreased by 10 s, requiring 3 fewer propulsive movements and 60% of the amount of force to propel the wheelchair compared with solid casters. Static and kinetic resistance tests did not differentiate the four caster types. Penetration into packed snow was reduced from 11.9 mm to approximately 1 mm by changing from solid casters to the FreeWheel™ or Wheelblades™ caster types on flat surfaces. Similar results were observed on a snow-covered incline for the Wheelblades™, however, the FreeWheel™ penetrated approximately 8 mm. Considering the entire body of evidence, the FreeWheel™ performed the best on snow-covered surfaces.

Assessment of the postural control strategies used to play two Wii Fit™ videogames.

The Nintendo Wii Fit™ may provide an affordable alternative to traditional biofeedback or virtual reality systems for retraining or improving motor function in populations with impaired balance. The purpose of this study was to evaluate postural control strategies healthy individuals use to play Wii Fit™ videogames. Sixteen young adults played 10 trials of Ski Slalom and Soccer Heading respectively. Centre of pressure (COP) excursion and three-dimensional movement data were acquired to determine variability in medial-lateral COP sway and shoulder-pelvic movement. While there was no difference in medial-lateral COP variability between games during trial 1, there was a significant difference after 10 trials. COP sway increased (59-75 mm) for Soccer Heading while it decreased (67-33 mm) for Ski Slalom from trial 1 to trial 10. During Ski Slalom participants demonstrated decreased shoulder and pelvic movement combined with increased pelvic-shoulder coupling. Conversely, participants demonstrated greater initial shoulder tilt when playing Soccer Heading, with no reduction in pelvic rotation and tilt. Participants decreased pelvic and trunk movements when skiing, suggesting a greater contribution of lower extremity control while they primarily used a trunk strategy to play Soccer Heading.

Influence of endogenous and exogenous orientations of attention on inhibition of return in a cross-modal target-target aiming task.

The authors conducted 2 experiments in which participants (N = 16 in each) executed successive unimanual aiming movements to target locations that were indicated by the onset of either an auditory or a visual stimulus. In Experiment 1 (exogenous orientation), inhibition of return (IOR) effects were observed, with reliable reaction time (RT) costs associated with movements returning to the same target and a trend toward larger IOR effects in left than in right space. There was no influence of stimulus modality on the magnitude of IOR. IOR was also observed in Experiment 2 (endogenous orientation), except the influence of stimulus modality reliably mediated those effect. In that case, IOR was evident only when the previous modality was visual and the current modality was auditory. Together, the results of those 2 experiments suggest that in situations in which 2 paired movements constitute the response criteria, IOR is both supramodal and lateralized to contralateral space.