Relationship between fractal property of gait cycle and severity of Parkinson´s disease

Parkinson´s disease (PD) is a neurodegenerative disorder characterized by degeneration of dopaminergic neurons, affecting motor controls by basal ganglia. Serious movement disorders such as tremor or gait disturbance are often observed, but early diagnosis of PD is difficult. From such a background, Detrended Fluctuation Analysis (DFA) attracts attention as one of the methods for analyzing the fluctuation of the gait cycle in recent years. Therefore, the aim of this study is to clarify the relationship between the fractal exponent of DFA and disease severity of the PD patients. We performed the DFA analysis of gait cycle in 200 meters´ walk of 17 PD patients and 12 healthy young people. Particularly, we divided PD patients based on the Hoehn and Yahr (HY) scale into an HY2 group (n=9) and an HY3 group (n=8) in order to examine the relation to disease severity. Results indicate that fractal exponent was significantly lower in both PD groups (HY2, HY3) compared to the young healthy person. Fractal exponent also tended to be lower for the HY3 group compared to the HY2 group, although this tendency for fractal exponent decreasing with the disease severity was not significant here. From these results, the randomness of gait fluctuation seems to related to the severity of PD, suggesting a possibility for diagnosis of PD using fluctuation analysis of gait.