Abstract Details

Title Delineating the anatomical basis of microsaccades using an ultrasensitive technique for detection of deficits in patients with MS

Topic Neuro-ophthalmology/Neuro-otology

Presentation(s) P15 - Poster Session 15 (5:30 PM-6:30 PM)

Poster/Presentation
Number 2-002

Background

MS is an inflammatory, degenerative, demyelinating disease of the central nervous system. The Tracking Scanning Laser Ophthalmoscope (TSLO), a high-resolution retinal eye-tracking device, can detect changes in fixational eye motion (FEM) with extraordinary sensitivity and these measures have strong correlations with disability levels. The anatomical basis of microsaccades remains poorly understood and constitutes one of the only major classes of eye movements where underlying pathways are not well described.

Objective To improve our understanding of the anatomical basis of microsaccades by evaluating brain regions that exhibit atrophy in correlation with sensitive measures of microsaccades.

Design/Methods

FEM videos and 3T MRI scans were recorded in 129 individuals diagnosed with MS (average disease duration 13.0 ± 10.4, average EDSS 2.5 ± 1.6). FEM metrics of main sequence slope (N=91), average number of microsaccades (N=129), and inter-eye differences in the average number of microsaccades (N=127) were calculated to compare with grey matter volumes via whole-brain voxel-based morphometry (VBM) analysis. Voxel-by-voxel correlations were performed between smoothed modulated gray matter images and each TSLO derived microsaccade metric accounting for age, total intracranial volume, and gender as potential confounders, at FWE-corrected p≤0.05.

Results

A deviation to the main sequence slope relationship between peak velocity and amplitude of microsaccades correlated with atrophy in the cerebellum, specifically in left and right areas of Crus I and II (P < 0.001, small world multi-comparison correction), with left cerebellar hemisphere cluster surviving FWE correction (P < 0.05). The variables for average microsaccades and the difference in average microsaccades between eyes showed correlation with cortical regions, however, neither survived FWE corrections.

Conclusions TSLO derived metrics showed a strongly significant negative correlation with underlying atrophy, specifically within cerebellar regions in MS. This finding gives important insight into the role the CRUS I & II regions of the cerebellum play in defining the main sequence relationship of microsaccades.

Authors/Disclosures
Christy K. Sheehy, PhD PRESENTER	Dr. Sheehy has received personal compensation for serving as an employee of C. Light Technologies, Inc. An immediate family member of Dr. Sheehy has received personal compensation in the range of $500-$4,999 for serving as a Consultant for C. Light Technologies, Inc.. Dr. Sheehy has stock in C. Light Technologies. Dr. Sheehy has received research support from C. Light Technologies, Inc. Dr. Sheehy has received intellectual property interests from a discovery or technology relating to health care.
	No disclosure on file
Christian Cordano, MD, PhD (UCSF)	Dr. Cordano has nothing to disclose.
Ari Green, MD (UCSF)	Dr. Green has received personal compensation in the range of $50,000-$99,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Pipeline Therapeutics. Dr. Green has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Bionure. Dr. Green has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for JAMA Neurology. The institution of Dr. Green has received research support from NINDS. The institution of Dr. Green has received research support from NMSS. The institution of Dr. Green has received research support from NIA. The institution of Dr. Green has received research support from Adelson Research Foundation. Dr. Green has received intellectual property interests from a discovery or technology relating to health care. Dr. Green has received personal compensation in the range of $500-$4,999 for serving as a Study Section with NINDS. Dr. Green has a non-compensated relationship as a Author with Viela Bio that is relevant to AAN interests or activities.