Observable Performance Does Not Fully Reflect Adaptive System Organization: A Multi-Level Analysis of Gait Dynamics Under Occlusal Constraint

In biomechanical systems, observable performance is often used as a proxy for underlying organization, although similar outputs may arise from different adaptive configurations.

This study considers the vertical dimension of occlusion (VDO) as a constraint applied to an adaptive neuromechanical system.

A single-case design in a patient with Parkinson's disease enabled repeated intra-individual gait observations under six occlusal probes.

Three complementary analytical levels were examined: (i) an aggregated scalar score of observable performance, (ii) a conceptual dynamical systems framework, and (iii) an exploratory UMAP representation of 55 standardized biomechanical variables from 270 M1 observations.

The revised Level 1 analysis showed that the relative ranking of OC2.5 and OC3 depended on score construction, while their scalar distributions remained close.

The Level 3 embedding showed substantial overlap among all six probes and did not identify independently separated condition-specific clusters.

OC2.5 and OC3 displayed limited centroid displacement but broad observation-level overlap.

The principal result is therefore representational non-identifiability: neither the aggregated score nor the selected low-dimensional embedding uniquely identifies an occlusal-condition-specific system state.

VDO is interpreted as a constraint parameter rather than a causal determinant.

The findings are exploratory, model dependent, and non causal.

They do not establish distinct physiological states, an optimal VDO, clinical thresholds, or diagnostic, predictive, mechanistic, or prescriptive validity.