Gait instability and compensatory mechanisms in Parkinson's disease with camptocormia: An exploratory study

Objective: Camptocormia has been considered to contribute to vertical gait instability and, at times, may also lead to forward instability in experimental settings in Parkinson's disease (PD). However, these aspects, along with compensatory mechanisms, remain largely unexplored. This study comprehensively investigated gait instability and compensatory strategies in PD patients with camptocormia (PD+CC).

Methods: Ten PD+CC, 30 without camptocormia (PD-CC), and 27 healthy controls (HCs) participated. Self-paced gait tasks were analyzed using three-dimensional motion capture systems to assess gait stability, spatiotemporal, and kinematic parameters. Unique cases with pronounced forward gait stability or instability were first identified, followed by group comparisons. Correlation analysis was performed to examine associations between trunk flexion angles (lower/upper) and gait parameters. Significance level was set at 0.05.

Results: Excluding one unique case, the PD+CC group showed a significantly lower vertical center of mass (COM) position (p=0.019), along with increased mediolateral COM velocity (p=0.004) and step width (p=0.013), compared to PD-CC group. Both PD groups showed higher anterior-posterior margin of stability than HCs (p<0.001). Significant correlations were found between lower/upper trunk flexion angles and a lower vertical COM position (r=-0.690/-0.332), as well as increased mediolateral COM velocity (r=0.374/0.446) and step width (r=0.580/0.474).

Conclusions: Most PD+CC patients exhibited vertical gait instability, increasing fall risk, and adopted compensatory strategies involving greater lateral COM shift and wider base of support, with these trends intensifying as trunk flexion angles increased. These findings may guide targeted interventions for gait instability in PD+CC.