No abstract

We compared postural performances in early stage Parkinson's disease (PD) patients and healthy subjects, and to determine if PD patients have infraclinical postural instability. Nine PD patients and 18 age- and sex-matched control subjects were recorded with open eyes (OE) and closed eyes (CE) using a force platform in static and dynamic conditions with a mobile platform allowing antero posterior and medio lateral oscillations. Oscillations of the mobile platform and balance strategy were quantified using both a force platform and the Vicon system. Under static conditions with both OE and CE, PD patients had a larger center foot pressure sway area than the control subjects (P = 0.007 and P = 0.04, respectively). Under dynamic conditions, the PD patients' sway area was greater than that of the control subjects in the CE antero posterior position (P = 0.04). Oscillations of the mobile platform were not different between the two groups. Lastly, all subjects used an ankle strategy, but PD patients had larger head oscillations than the control subjects. Early stage PD patients have an infraclinical postural instability which is compensated when it is more difficult to maintain good balance, suggesting that the neurological mechanisms of balance are partially still operating at this stage of the disease.

While gait variability may reflect subtle changes due to aging or cognitive impairment (CI), associated brain characteristics remain unclear. We summarize structural and functional neuroimaging findings associated with gait variability in older adults with and without CI and dementia. We identified 17 eligible studies; all were cross-sectional; few examined multiple brain areas. In older adults, temporal gait variability was associated with structural differences in medial areas important for lower limb coordination and balance. Both temporal and spatial gait variability were associated with structural and functional differences in hippocampus and primary sensorimotor cortex and structural differences in anterior cingulate cortex, basal ganglia, association tracts, and posterior thalamic radiation. In CI or dementia, some associations were found in primary motor cortex, hippocampus, prefrontal cortex and basal ganglia. In older adults, gait variability may be associated with areas important for sensorimotor integration and coordination. To comprehend the neural basis of gait variability with aging and CI, longitudinal studies of multiple brain areas are needed.