Objective: To investigate eye movement changes as an early motor biomarker of Parkinson’s disease (PD) in patients with REM sleep behavior disorder (RBD).
Background: RBD is a disease known as a prodromal symptom of PD, but it is a non-motor symptom and must be accompanied by motor symptoms necessary for PD diagnosis. In PD, a decrease in saccade is known, and eye movements are predicted by gaze analysis to detect it, and the patient group with Parkinson’s disease that meets the diagnostic criteria of MDS, the group of RBD patients with all-night EEG or questionnaire, and the healthy control group are compared, and follow-up is performed prospectively.
Method: We validate eye-tracking from diagnosed PD patients (n = 33), pre-motor individuals with isolated RBD (n = 14), and healthy controls (n = 34). The following tests were reviewed and statistically analyzed: gaze analysis and pupil diameter (Tobii prospectrum 1200), MDS-Unified Parkinson’s Disease Rating Scale, stabilizing test (Gravicorder GS-31), neuropsychological tests (Mini-Mental State Examination, Montreal Cognitive Assessment Japanese, Clock Drawing Test, Wechsler Adult Intelligence Scale-III-building block problem, Line orientation, Dot counting, Position discrimination, and Cube analysis).
Results: 33 PDs, 14 RBDs, and 34 healthy controls were registered. Significant differences were observed between the groups at the time of enrollment in saccade duration, saccade distance, and pupil size from eye tracking. In the RBD group, the average follow-up was 3.4 years after enrollment, and 3 patients developed PD 1, 3, and 4 years after enrollment, and the patients who developed PD had large pupil fluctuations at enrollment and low Moca-J, line orientation, and clock drawing.
Conclusion: Before the onset of PD, there were decreased eye movements and pupil changes in the patients with RBD known as preclinical symptoms. We will analyze and report on further patient enrollment and follow-up.
To cite this abstract in AMA style:
A. Yoritaka, M. Ando, S. Nakayama, K. Fusegi, S. Nojiri, A. Tozuka, Y. Wang, W. Urasaki, N. Hattori. Eye tracking identifies biomarkers predicting Parkinson’s disease before motor symptom onset [abstract]. Mov Disord. 2025; 40 (suppl 1). https://www.mdsabstracts.org/abstract/eye-tracking-identifies-biomarkers-predicting-parkinsons-disease-before-motor-symptom-onset/. Accessed October 5, 2025.« Back to 2025 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/eye-tracking-identifies-biomarkers-predicting-parkinsons-disease-before-motor-symptom-onset/