Tactile stimuli affect long-range correlations of stride interval and stride length differently during walking.

Sensory feedback below the sole of the foot using sub-threshold mechanical noise significantly reduced postural sway in patients with diabetes and stroke. However, the effects of tactile parameters on walking are still elusive. Specifically, the effects of such parameters on human gait variability need to be studied because of possible rehabilitation outcomes in terms of bringing improvement in temporal and spatial gait parameters. The purpose of this study was to investigate whether different frequency and amplitude combinations of vibro-tactile stimulation of feet would affect stride-to-stride variability in healthy young adults. Ten healthy subjects walked on a treadmill at self-selected pace while wearing customized insoles fitted with tactors that vibrated at selected frequencies and amplitudes. The results show that the frequency manipulations of tactile stimulation altered the long-range correlations (LRCs) in stride length while amplitude manipulations affected the LRCs in stride interval without having any effect on the amount of gait variability. Our findings suggest that independent neural mechanisms may be responsible for coordinating LRCs of gait parameters in the spatial and temporal domains.

Constraining eye movement in individuals with Parkinson's disease during walking turns.

Walking and turning is a movement that places individuals with Parkinson's disease (PD) at increased risk for fall-related injury. However, turning is an essential movement in activities of daily living, making up to 45 % of the total steps taken in a given day. Hypotheses regarding how turning is controlled suggest an essential role of anticipatory eye movements to provide feedforward information for body coordination. However, little research has investigated control of turning in individuals with PD with specific consideration for eye movements. The purpose of this study was to examine eye movement behavior and body segment coordination in individuals with PD during walking turns. Three experimental groups, a group of individuals with PD, a group of healthy young adults (YAC), and a group of healthy older adults (OAC), performed walking and turning tasks under two visual conditions: free gaze and fixed gaze. Whole-body motion capture and eye tracking characterized body segment coordination and eye movement behavior during walking trials. Statistical analysis revealed significant main effects of group (PD, YAC, and OAC) and visual condition (free and fixed gaze) on timing of segment rotation and horizontal eye movement. Within group comparisons, revealed timing of eye and head movement was significantly different between the free and fixed gaze conditions for YAC (p < 0.001) and OAC (p < 0.05), but not for the PD group (p > 0.05). In addition, while intersegment timings (reflecting segment coordination) were significantly different for YAC and OAC during free gaze (p < 0.05), they were not significantly different in PD. These results suggest individuals with PD do not make anticipatory eye and head movements ahead of turning and that this may result in altered segment coordination during turning. As such, eye movements may be an important addition to training programs for those with PD, possibly promoting better coordination during turning and potentially reducing the risk of falls.

Assessment of oculomotor control and balance post-concussion: a preliminary study for a novel approach to concussion management.

PRIMARY OBJECTIVE: Balance disturbances occur in ∼30% of concussion injuries, with vestibular dysfunction reported as the main contributor. However, few have studied oculomotor control post-concussion to assess vestibular dysfunction. RESEARCH DESIGN: The current research measured the differences in oculomotor control between athletes post-concussion (PC) and athletes without concussion (NC) during an active balance control task. METHODS: Nine PC and nine NC athletes wore a monocular eye tracking device, while balance tests were performed using the Nintendo WiiFit® soccer heading game. Average game scores, eye deviations from centre (Gaze Deviations) and gaze fixation (Percentage Time on Centre) were measured. RESULTS: PC made significantly greater Gaze Deviations from centre compared to NC (p < 0.001), however Percentage Time on Centre and game scores were not significantly different between groups. Correlations between gaze and balance within groups revealed a significant positive correlation in NC, while a significant negative correlation in PC. CONCLUSIONS: Results from this exploratory examination of oculomotor behaviour post-concussion revealed significant differences in gaze stability between athletes with a concussion and those without, suggesting vestibular involvement post-concussion. Assessment of oculomotor control during balance activities may provide further insight into dysfunction of the vestibular system following a concussion injury.

Dead Bodybuilders Speaking from the Heart: An Analysis of Autopsy Reports of Bodybuilders That Died Prematurely.

This study analyzed publicly available autopsy reports of male bodybuilders under the age of 50 who reportedly died from cardiovascular-related events. A general Google search with the terms "dead bodybuilders" was performed on 10 February 2022. Six reports were available for review and analysis. Bodybuilders had the following means: age (±SD) = 36 ± 7.1 years; height 1.82 ± 0.02 m; weight = 103.8 ± 5.3 kg; weight of heart = 575 ± 134.4 g; and left ventricular myocardium thickness (n = 3) = 16.3 ± 3.5 mm. The bodybuilders analyzed had a mean heart weight that is 73.7% heavier than the reference man (575 g vs. 332 g). Similarly, 100% of the autopsies reported left ventricular myocardium thickness of 16.3 ± 3.5 mm; this is 125% thicker than normative data for men. While abuse of AASs for prolonged periods of time may contribute to some of the cardiac abnormalities present in these bodybuilders, it should be noted that cardiac hypertrophy, including left ventricular hypertrophy, has also been reported in drug-free strength athletes. Each autopsy report included cardiovascular abnormalities within the cause of death. Association does not mean causation, but nonetheless bodybuilders should be aware of potential contributing cardiovascular risks with AAS abuse.

Simulated visual field loss does not alter turning coordination in healthy young adults.

Turning, while walking, is an important component of adaptive locomotion. Current hypotheses regarding the motor control of body segment coordination during turning suggest heavy influence of visual information. The authors aimed to examine whether visual field impairment (central loss or peripheral loss) affects body segment coordination during walking turns in healthy young adults. No significant differences in the onset time of segments or intersegment coordination were observed because of visual field occlusion. These results suggest that healthy young adults can use visual information obtained from central and peripheral visual fields interchangeably, pointing to flexibility of visuomotor control in healthy young adults. Further study in populations with chronic visual impairment and those with turning difficulties are warranted.