Bite height changes show hidden gait stability differences in Parkinson's study

A new exploratory study from Jacques Raynal and colleagues introduces a fourth analytical level—longitudinal viability—to understand how adaptive systems like human gait respond to occlusal constraints. Using a single Parkinson's patient, they recorded gait data with instrumented insoles under three conditions: neutral occlusion (ONL), a 2.5° increase in vertical dimension (OC2.5), and a 3° increase (OC3). Two sessions were conducted 11 weeks apart, with a sensorimotor intervention in between.

Despite globally comparable observable performance (e.g., speed, step length), PCA-based latent-space analysis revealed that OC3 exhibited the smallest centroid displacement over time, ONL intermediate, and OC2.5 the largest. This suggests that different bite heights produce distinct hidden organizational states, with OC3 providing the most stable trajectory. The authors argue that clinical assessments should move beyond raw performance metrics to consider the latent capacity for sustained organization—what they term 'viability.' The work is exploratory and non-causal, but points to a richer framework for neuromechanical adaptation.