# Differences Between Patients With Multiple System Atrophy With Predominant Parkinsonism and Parkinson's Disease Based on fNIRS and Gait Analysis

## TL;DR

This study compares gait and brain activity in MSA-P and Parkinson's disease patients during walking tasks to identify distinguishing features.

## Contribution

The study identifies increased DLPFC activity and gait variability in MSA-P patients during dual-task walking as potential diagnostic markers.

## Key findings

- MSA-P patients showed higher step length variability and DLPFC activity during dual-task walking compared to PD patients and healthy controls.
- ΔHbO2 in the right DLPFC during dual-task walking had high specificity for distinguishing MSA-P patients.
- A significant interaction effect was found in the right DLPFC between MSA-P and PD patients during dual-task walking.

## Abstract

To investigate the differences in gait parameters and cortical activity during a single‐task walking (STW) and cognitive dual‐task walking (DTW) between multiple system atrophy with predominant parkinsonism (MSA‐P) and Parkinson's disease (PD).

24 MSA‐P patients, 20 PD patients, and 22 healthy controls (HCs) were enrolled. Gait parameters were collected using a portable inertial measurement unit system, and the relative change of oxyhemoglobin (ΔHbO2) in the bilateral frontal and sensorimotor cortex was obtained by functional near‐infrared spectroscopy during walking with and without cognitive tasks.

MSA‐P patients had increased step length variability and higher ΔHbO2 in the right dorsolateral prefrontal cortex (DLPFC), relative to PD patients and HCs during the DTW condition. Meanwhile, MSA‐P patients exhibited higher step length variability and ΔHbO2 in the right DLPFC during DTW compared to STW. Furthermore, mild negative correlations were found between the ΔHbO2 in the right DLPFC and step length, while there was a mild positive correlation between ΔHbO2 and step length variability during the DTW condition. Notably, receiver operating characteristic (ROC) curve analysis uncovered that the areas under the curve (AUCs) of the ΔHbO2 of the right DLPFC and step length variability during DTW were 0.798 (95% confidence interval [CI]: 0.651–0.945, sensitivity = 0.650, specificity = 0.958) and 0.721 (95% CI: 0.570–0.871, sensitivity = 0.625, specificity = 0.800), respectively.

MSA‐P patients demonstrate more severe gait disturbance and increased DLPFC activity compared with PD patients and HCs. Gait parameters and cortical activity could be a potential features discerning MSA‐P patients and PD patients.

We found a significant interaction effect between group and condition in the right dorsolateral prefrontal cortex. Bonferroni post hoc tests indicated MSA‐P patients exhibited a significant increase in ΔHbO2 compared to PD patients during the DTW condition.