Eye movement evaluation in Multiple Sclerosis and Parkinson’s Disease using a Standardized Oculomotor and Neuro-ophthalmic Disorder Assessment (SONDA)

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 (Standardised 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.

A novel tablet-based software for the acquisition and analysis of gaze and eye movement parameters: a preliminary validation study in Parkinson’s disease

“…Similarly, findings regarding peak velocity have been mixed, with a few studies finding faster velocities in PD (Lu et al, 2019;Grillini et al, 2020), whereas most other studies found no differences between PD and healthy control (Blekker et al, 2009;Stuart et al, 2013;Gorges et al 2013;Zhou et al, 2021;Gitchel et al, 2012). In the present study, we find peak and mean velocities to be significantly increased in PD patients (only uncorrected p-value for peak velocity) for short eccentricity targets only.…”

Abnormalities of the oculomotor function in type 1 diabetes and diabetic neuropathy

“…Indeed, the number of patients with T1D and neuropathy, in this study is limited, and the study selection process that excluded retinopathy but included neuropathy may have also inadvertently defined a sub-population of patients with some predisposition for early development of neuropathy, who could be further investigated for other disease markers [37]. The clinical relevance of this non-invasive test to identify and screen altered eye movement patterns has been already established in other neurologic diseases (e.g., amyotrophic lateral sclerosis, Alzheimer's disease, Parkinson's disease, multiple sclerosis, and epilepsy) [38,39], in which a cognitive disorder has been often recognized [19] and progression of the disease is hardly measurable [40]. Moreover, this method particularly recognizes alterations in rapid (saccades, velocity) and slow eye movements (smooth pursuit) and in some specific features (e.g., wideness and resistance), which are primarily under the control of the central nervous system.…”

Movement Disorder in Demyelinating Disease

“…[ 174 ] Besides this, nystagmography was also used in some studies for illustrating the slowing of saccades. [ 174 175 ] However, these parameters act as indicators but cannot be fully relied on. [ 175 ]…”

“…Saccades can be measured by infrared reflection oculography, infrared oculography, infrared eye-tracker, electro-oculographic technique, and the combination of infrared oculography and diffusion tensor imaging (DTI). [ 175 ] Various medications have been tried to improve the latency of saccades, including fampridine. [ 176 ]…”