Although motion analysis is frequently employed in upper limb motor assessment (e.g. visually-guided reaching), they are resource-intensive and limited to laboratory settings. This study evaluated the reliability and accuracy of a new markerless motion capture device, the Leap Motion controller, to measure finger position. Testing conditions that influence reliability and agreement between the Leap and a research-grade motion capture system were examined. Nine healthy young adults pointed to 15 targets on a computer screen under two conditions: (1) touching the target (touch) and (2) 4 cm away from the target (no-touch). Leap data was compared to an Optotrak marker attached to the index finger. Across all trials, root mean square (RMS) error of the Leap system was 17.30  ±  9.56 mm (mean ± SD), sampled at 65.47  ±  21.53 Hz. The % viable trials and mean sampling rate were significantly lower in the touch condition (44% versus 64%, p < 0.001; 52.02  ±  2.93 versus 73.98  ±  4.48 Hz, p = 0.003). While linear correlations were high (horizontal: r(2) = 0.995, vertical r(2) = 0.945), the limits of agreement were large (horizontal: -22.02 to +26.80 mm, vertical: -29.41 to +30.14 mm). While not as precise as more sophisticated optical motion capture systems, the Leap Motion controller is sufficiently reliable for measuring motor performance in pointing tasks that do not require high positional accuracy (e.g. reaction time, Fitt's, trails, bimanual coordination).

Manual asymmetries has been studied by many researchers, however contradictory findings still exist as to whether preferred manual asymmetries increases with age or do we become more ambidextrous. Recently it was shown that perhaps there is a third option, that there is no increase or decrease in laterality but rather preferred manual asymmetries remains consistent throughout adulthood. Another related finding is that females appear to have an advantage in some handedness tasks, such as the Grooved Pegboard. When a larger pegboard is used, sex differences may reverse as males may perform better when larger pegs and a larger trajectory are required. However, it is not fully understood if these sex differences arise from an early age and continue throughout life. Therefore, we sought to explore sex differences in preferred hand dominance throughout the lifespan. In order to explore preferred hand dominance during the lifespan we examined 76 children (19.4–5 year olds, 12 female, Mage = 4.73; 34.6–8 year olds, 12 female, Mage = 6.97; 23.9–12 year olds, 14 female, Mage = 10.83) in Experiment 1 and 35 healthy young right-handed adults (15 female, Mage = 20.91) and 37 healthy older right-handed adults (20 female, Mage = 72.3) in Experiment 2. Individuals were tested using a standard size (small) and modified Grooved Pegboard (larger pegboard). Our study demonstrates that hand asymmetries are present early in life (children 4–5 years old) at that these differences attenuate as a function of age until adulthood (Experiment 1). Furthermore, our results demonstrate that as we age (Experiment 2), asymmetries may increase (small and large pegboards), decrease (Annett), or stay the same (finger tapping). As well we demonstrated that the sex differences could not be entirely accounted for by hand size. Therefore, asymmetries as regard to the aging process, seems to be task specific which may account for the conflicting findings in research.

The purpose of this study was to examine executive functions in team sport athletes with and without a history of concussion. Executive functions comprise many cognitive processes including, working memory, attention and multi-tasking. Past research has shown that concussions cause difficulties in vestibular-visual and vestibular-auditory dual-tasking, however, visual-auditory tasks have been examined rarely. Twenty-nine intercollegiate varsity ice hockey athletes (age = 19.13, SD = 1.56; 15 females) performed an experimental dual-task paradigm that required simultaneously processing visual and auditory information. A brief interview, event description and self-report questionnaires were used to assign participants to each group (concussion, no-concussion). Eighteen athletes had a history of concussion and 11 had no concussion history. The two tests involved visuospatial working memory (i.e., Corsi block test) and auditory tone discrimination. Participants completed both tasks individually, then simultaneously. Two outcome variables were measured, Corsi block memory span and auditory tone discrimination accuracy. No differences were shown when each task was performed alone; however, athletes with a history of concussion had a significantly worse performance on the tone discrimination task in the dual-task condition. In conclusion, long-term deficits in executive functions were associated with a prior history of concussion when cognitive resources were stressed. Evaluations of executive functions and divided attention appear to be helpful in discriminating participants with and without a history concussion.

The purpose of this study was to examine the role of binocular vision during a prehension task performed in a visually enriched environment where the target object was surrounded by distractors/obstacles. Fifteen adults reached and grasped for a cylindrical peg while eye movements and upper limb kinematics were recorded. The complexity of the visual environment was manipulated by varying the number of distractors and by varying the saliency of the target. Gaze behavior (i.e., the latency of the primary gaze shift and frequency of gaze shifts prior to reach initiation) was comparable between viewing conditions. In contrast, a binocular advantage was evident in performance accuracy. Specifically, participants picked up the wrong object twice as often during monocular viewing when the complexity of the environment increased. Reach performance was more efficient during binocular viewing, which was demonstrated by shorter reach reaction time and overall movement time. Reaching movements during the approach phase had higher peak velocity during binocular viewing. During monocular viewing reach trajectories exhibited a direction bias during the acceleration phase, which was leftward during left eye viewing and rightward during right eye viewing. This bias can be explained by the presence of esophoria in the covered eye. The grasping interval was also extended by ~20% during monocular viewing; however, the duration of the return phase after the target was picked up was comparable across viewing conditions. In conclusion, binocular vision provides important input for planning and execution of prehension movements in visually enriched environments. Binocular advantage was evident, regardless of set size or target saliency, indicating that adults plan their movements more cautiously during monocular viewing, even in relatively simple environments with a highly salient target. Nevertheless, in visually-normal adults monocular input provides sufficient information to engage in online control to correct the initial errors in movement planning.

The authors examined the patterns of expert and less skilled golfers in putting on an indoor surface to 1 of 3 circular targets (1, 3, and 5 m away) in trials with a ball present (and putted) or not present (a practice stroke). As expected, the experts performed better than the less skilled golfers on a large number of outcome and kinematic measures. Displacement and velocity profiles of the head and putter revealed high positive correlations for the less skilled golfers, indicating a dominant allocentric coordination pattern, but high negative correlations for the expert golfers, indicating a dominant egocentric coordination pattern. The observed coordination patterns did not interact with the distance of the intended putt or the presence/absence of a ball. These findings offer preliminary evidence that, although contrary to traditional beliefs, fundamental differences exist in putting coordination modes between expert and less skilled golfers.