同一患者在不同咬合高度下步态表现相似,但神经肌肉系统组织方式可能不同。
Observable Performance Does Not Fully Reflect Adaptive System Organization: A Multi-Level Analysis of Gait Dynamics Under Occlusal Constraint

- 通过六种咬合干预重复观测帕金森患者步态,分析多层级数据
- 不同咬合条件下的步态指标分布重叠严重,无独立集群
- 提示表面表现无法反映系统内在组织差异,适用于临床研究设计反思
在生物力学系统中,可观测表现常被用作底层组织的代理指标,尽管相同输出可能源于不同适应性配置。本研究将垂直咬合维度(VDO)作为施加于自适应神经机械系统的约束。采用单病例设计,在一名帕金森病患者身上进行六种咬合干预下的重复步态观测,共获得270次M1观测数据。分析包含三个互补层次:(i) 可观测表现的聚合标量评分,(ii) 概念性动力系统框架,(iii) 基于55个标准化生物力学变量的探索性UMAP嵌入表示。修正后的第1层分析显示,OC2.5与OC3的相对排名依赖于评分构建方式,但其标量分布仍高度接近。第3层嵌入显示所有六种干预条件间存在显著重叠,未识别出独立分离的条件特异性聚类。OC2.5与OC3仅表现出有限的质心位移,但在观测层面存在广泛重叠。主要结论为表征非唯一性:无论聚合评分还是选定的低维嵌入,均无法唯一标识特定咬合条件下的系统状态。因此,VDO被解释为约束参数而非因果决定因素。研究结果为探索性、模型依赖且非因果,未建立明确生理状态、最优VDO、临床阈值,也未具备诊断、预测、机制或处方有效性。
原文摘要 · Abstract (English)
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.
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