# Gait dysfunction as an early marker of phenoconversion in REM sleep behavior disorder

## TL;DR

Gait analysis can predict early signs of Parkinson's disease in patients with REM sleep behavior disorder.

## Contribution

Gait rhythm parameters can distinguish imminent phenoconversion in iRBD patients.

## Key findings

- Gait velocity and endurance were lower in iRBD patients compared to controls.
- Gait rhythm parameters like single support differentiate PD from iRBD and controls.
- Gait analysis predicts imminent phenoconversion in iRBD patients.

## Abstract

Clinical isolated REM Sleep Behavior Disorder (iRBD) is a prodromal stage of α-synucleinopathies such as Parkinson’s disease (PD). Longitudinal changes of gait as a marker of phenoconversion in iRBD have not been systematically evaluated yet. Therefore, twenty-one iRBD patients, nineteen matched healthy controls and fourteen PD patients (H&Y stage I - III) were assessed at baseline using a pressure-sensor walkway (GAITRite). While normalized gait velocity and walking endurance were significantly decreased in iRBD patients compared to controls, gait rhythm parameters such as single support further discriminated PD from iRBD and controls. IRBD patients at imminent risk of phenoconversion within the next 3.7 ± 0.6 years were distinguishable from non-converters by gait rhythm parameters such as single support. Since gait evaluation of our iRBD cohort showed promising results in predicting imminent phenoconversion, future multicenter trials should include gait analysis as an objective assessment of motor function to confirm our results.

The online version contains supplementary material available at 10.1038/s41598-026-37925-w.