Eye Movement Evaluation in Multiple Sclerosis and Parkinson's Disease Using a Standardized Oculomotor and Neuro-Ophthalmic Disorder Assessment (SONDA).

Alessandro Grillini,Anne C. L. Vrijling,Remco J. Renken,Frans W. Cornelissen,Joost Heutink

doi:10.3389/fneur.2020.00971

Alessandro Grillini, Anne C. L. Vrijling + Show 3 more

Open Access

https://doi.org/10.3389/fneur.2020.00971

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Abstract

Evaluating the state of the oculomotor system of a patient is one of the fundamental tests done in neuro-ophthalmology. However, up to date, very few quantitative standardized tests of eye movements' quality exist, limiting this assessment to confrontational tests reliant on subjective interpretation. Furthermore, quantitative tests relying on eye movement properties, such as pursuit gain and saccade dynamics are often insufficient to capture the complexity of the underlying disorders and are often (too) long and tiring. In this study, we present SONDA (Standardized Oculomotor and Neurological Disorder Assessment): this test is based on analyzing eye tracking recorded during a short and intuitive continuous tracking task. We tested patients affected by Multiple Sclerosis (MS) and Parkinson's Disease (PD) and find that: (1) the saccadic dynamics of the main sequence alone are not sufficient to separate patients from healthy controls; (2) the combination of spatio-temporal and statistical properties of saccades and saccadic dynamics enables an identification of oculomotor abnormalities in both MS and PD patients. We conclude that SONDA constitutes a powerful screening tool that allows an in-depth evaluation of (deviant) oculomotor behavior in a few minutes of non-invasive testing.

Highlights

Eye movements are a fundamental component of vision
We find that the main-sequence alone is often insufficient to detect the presence of oculomotor abnormalities in either Multiple Sclerosis (MS) or Parkinson’s Disease (PD)
When we combine the spatio-temporal properties (STP) with saccadic dynamics and frequency distributions, both PD and MS patients can be distinguished from controls

Summary

Introduction

Eye movements are a fundamental component of vision. Their evaluation is an important aspect of assessments in neurology and ophthalmology. Two neurological conditions in which oculomotor assessment has great clinical relevance are Multiple Sclerosis (MS) and Parkinson’s Disease (PD). In MS, the oculomotor assessment is relevant for diagnosis, for monitoring progress and for prognosis [1,2,3], while in Parkinson’s Disease (PD), eye-movements can help in differentiating the “pure” form of PD from other forms of parkinsonism [4,5,6]. For both MS and PD, a confrontational assessment is the most commonly used technique for evaluating patients’ eye motility. In cases like sub-clinical manifestations of internuclear ophthalmoplegia in MS, or in PD, which typically exhibit eye movement disorders that are present in the healthy elderly population, quantitative approaches are crucially needed [7]

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