Association of Stride Rate Variability and Altered Fractal Dynamics with Ageing and Neurological Functioning

Alterations in gait cycle i.e stride rate show fractal dynamics and lower limb walking variability between healthy controls and the controls associated to any neurological disorder. The paper proposes a study in which these stride variability changes in neurological functioning linked with individuals with neurocognitive disorder and accumulation of changes happen in the human body with time called ageing. To validate this research work, we compared the participants' gait cycle in time series: 1) healthy young participants and healthy older adults 2) subjects with Parkinson's disease (PD) and disease-free subjects. Using the Detrended Fluctuation Analysis (DFA) method we computed $\alpha$ , a measure of a degree to which one stride time is compared with the previous and the consecutive intervals over a various time span. The scaling exponent $\alpha$ is exigently curtailed in older adults as compared to young healthy participants. The scaling exponent $\alpha$ is also lower in the subjects with PD compared with the disease-free participants. Moreover, $\alpha$ seems linearly correlated to the degree of functional impairment in subjects with PD. These findings demonstrate that stride time fluctuations are more arbitrary in elderly subjects and in subjects with PD. Abnormal fluctuations in the fractal properties of lower limb dynamics are clearly related to functioning in central nervous system control.