Follow-up observation of eye movements in multiple system atrophy and Parkinson's disease: a cohort study.

Abstract

Objectives: We aimed to explore the changes in oculomotor deficiencies during the follow-up of patients with multiple system atrophy (MSA) and Parkinson's disease (PD), and to investigate the value of dynamic eye movement examination in their differential diagnosis.

Design: This was a cohort study conducted from 2017 to 2023.

Setting: The Movement Disorders Clinic at a tertiary hospital in Beijing, China.

Participants: 56 patients with PD and 13 patients with MSA from an initial cohort of over 1100 with parkinsonism were included in the final longitudinal analysis.

Outcome measures: Multisystem evaluations were performed at baseline. Videonystagmography (VNG) was repeated to assess oculomotor dysfunction at baseline and during follow-up. Abnormalities in the fixation and gaze-holding test, without-fixation test, reflexive and memory-guided saccade tests, smooth pursuit test and optokinetic test were qualitatively and quantitatively recorded and statistically analysed.

Results: The median follow-up time of MSA (16 months) was significantly shorter than that of PD (27 months). In MSA, the incidence of abnormalities in fixation and gaze-holding tests (0% vs 30.8%, p=0.030), reflexive saccade tests (46.2% vs 84.6%, p=0.039, with slow saccades increasing from 7.7% to 46.2%, p=0.027) and smooth pursuit tests (38.5% vs 76.9%, p=0.047) increased significantly from baseline to the end of follow-up. In PD, no significant changes were revealed during follow-up.

Conclusions: MSA exhibited more rapid and prominent changes in fixation and gaze-holding tests, reflexive saccades and smooth pursuit tests than PD. Dynamic observation of oculomotor function may aid in the differential diagnosis of Parkinson's syndrome.