Whole body analysis of functional communities and topological features of gait with different speeds in Parkinson’s disease

BACKGROUND: During human gait, different body segments work coherently to achieve forward propulsion in a coordinated manner. It is known that Parkinson's disease (PD) disturbs this coordination, however, which body segments contribute most, especially with changing walking speed, has not been evaluated. OBJECTIVES: To investigate in people with PD (PwPD) and healthy controls how individual body segments contribute to altered gait during different walking speeds. METHODS: Twenty-nine PwPD and 29 controls walked forward along a straight walking path at three walking speeds. For each speed and movement direction, kinectomes were built by computing pairwise correlations between body segment accelerations. Network graphs were generated with anatomical segments as nodes and their co-accelerations as edges. Graph-theoretic analysis examined community organisation, modularity metrics, and network topology. Nodal strength, defined as coherence between a body segment and all other body segments, was extracted. RESULTS: Compared to controls, PwPD showed coherence deficits during walking, particularly at preferred speed and in the anteroposterior direction, and these deficits primarily affected the core body segments. Controls demonstrated speed-dependent modulation of coherence that was absent in PwPD, particularly in the anteroposterior direction within core body segments. Moreover, PwPD showed speed-dependent modulation of coherence primarily in lower limb segments across the mediolateral and vertical directions. CONCLUSION: In PwPD, gait coordination deficits localise primarily to the core body segments and are accompanied by a reduced ability to modulate whole-body coordination with walking speed, suggesting that trunk-focused and progressive speed-variable gait training may be a particularly effective rehabilitation strategy. The graph-theoretical framework further enables individualised identification of segmental coordination deficits for tailored treatment planning. TRIAL REGISTRATION: The study is registered in the German Clinical Trials Register (DRKS00022998, registered on 04 Sep 2020).