Network Analysis of Bodywide Coordination Supporting Suprapostural Dexterity

Study Summary

Prevailing understandings of movement disorders characterize "broken" movements in a piecewise fashion, for instance, focusing on motor control, muscle tone, posture, or cognition independently of each other. These fractured approaches to movement coordination are blind to the body's functional integrity. Consequently, rehabilitative interventions target the limb or body parts most affected by the disorder, seeking to support the whole body by mending the broken part. However, dexterity is global, functional coordination spanning the whole body. In other words, task completion draws on fundamental interactivity, allowing the body to coordinate various anatomical parts. This coordination may be more vital to healthy movement than individual anatomical parts. Understanding this interactivity is thus paramount to developing novel rehabilitative interventions to prevent falls and improve the quality of life in pathological populations. Studying bodywide coordination for suprapostural dexterity requires innovation in experimental setup and analytical techniques. This project integrates a customizable life-size Trail Making Test with posturography, whole-body movement tracking, eye tracking, and state-of-the-art cascade modeling and network analysis methods to assess functional coordination across the whole body. The experimenters will leverage causal network analyses of multiplicative interactions instrumental in previous studies of whole-body exploratory motor behavior but not yet utilized in studying suprapostural dexterity. Aim 1 will investigate how multiplicative interactions among movement-system components support suprapostural dexterity. The experimenters hypothesize that maintaining an upright stance would produce a functional network of multiplicative interactions among movement-system components. The experimenters also hypothesize that participating in the Trail Making Test would produce a succession of distinct, modular networks of multiplicative interactions

Primary Outcome

The outcome measure characterizes the directional, weighted network of multiplicative interactions across the human movement system, derived from vector autoregression (VAR) analysis of multifractal fluctuations in center-of-pressure (CoP), center-of-mass (CoM), and 79 anatomical marker displacement series. Each node in the network represents a body segment or anatomical location, and each edge captures the strength and direction of influence in nonlinear fluctuation propagation across time. The

Interventions

• BEHAVIORAL Trail Making Task
• BEHAVIORAL Balance board