GaitEncoder: A Foundation Model of Gait Kinematics for Clinical Applications Across Diverse Pathologies

R. Daniel Magruder, Selim Gilon, Antoine Falisse, Scott D. Uhlrich

Movement Bioengineering Lab, University of Utah

Abstract

Graphical abstract summarizing the GaitEncoder pipeline and clinical applications

Background. Regular gait analysis could enhance personalised treatment for many movement-related conditions; however, it is not routinely integrated into clinical care. Although mobile sensing (e.g. smartphone-based motion capture) enables rapid gait assessment, extracting actionable insights remains a challenge.

Objective. We introduce GaitEncoder, a generative foundation model that encodes high-dimensional 3D gait kinematics into a compact 16-dimensional latent space and enables clinically meaningful downstream tasks across diverse pathologies.

Methods. We aggregated eight datasets comprising 657 individuals (age 8-86) spanning seven pathologies and trained a weakly-supervised variational autoencoder. We evaluated the clinical utility of this model on multiple various downstream tasks.

Results. We show that this representation enables four downstream clinical tasks across both in- and out-of-distribution pathologies, with and without model fine-tuning, including: 1) classification of neuromuscular disorders unseen during training, 2) predicting clinical severity scores for individuals with Parkinson’s Disease, 3) tracking of subacute recovery post-stroke, and 4) generating patient-specific kinematic changes following total hip arthroplasty. Our model also computes a Distance from Mean Unimpaired (DMU) score, a scalar metric that captures an individual’s deviation from typical unimpaired gait for rapid quantification of impairment.

Significance. Our GaitEncoder provides a generalizable representation which may accelerate the development of clinical tools for monitoring disease progression, guiding rehabilitation, and informing surgical decisions, particularly for rare movement-related disorders.

Example Reconstructions

The grey skeleton shows the original motion capture. Our model distills kinematics to 16 features, which are decoded and visualized as the purple skeleton. 16 features is sufficient to retain salient, clinically relevant gait information. The DMU score (Distance from Mean Unimpaired) quantifies each example’s deviation from unimpaired gait, with a larger score being further from the unimpaired cohort.

Generative Representations of Gait

Adjust the 16 latent features and click Visualize to generate a gait stride through the VAE and see it rendered in 3-D.

Distribution of DMU scores by population

DMU (Distance from Mean Unimpaired) measures how far each individual's gait is from the reference distribution of unimpaired walking. This plot shows the distribution of DMU values across different patient populations. The reference mean is 1.0, higher values are increasingly more likely to be impaired.