Prosaccade and Antisaccade Behavior in Fragile X-Associated Tremor/Ataxia Syndrome Progression

Mov Disord Clin Pract. 2022 Apr 28;9(4):473-478. doi: 10.1002/mdc3.13449. eCollection 2022 May.

Abstract

Background: Quantitative measurement of eye movements can reveal subtle progression in neurodegenerative diseases.

Objective: To determine if quantitative measurements of eye movements may reveal subtle progression of fragile X-associated tremor and ataxia (FXTAS).

Methods: Prosaccade (PS) and antisaccade (AS) behavior was analyzed in 25 controls, 57 non-FXTAS carriers, and 46 carriers with FXTAS.

Results: Symptomatic individuals with FXTAS had longer AS latencies, increased rates of AS errors, and increased AS dysmetria relative to non-FXTAS carriers and controls. These deficits, along with PS latency and velocity, were greater in advanced FXTAS stages.

Conclusion: AS deficits differentiated FXTAS from non-FXTAS premutation carriers implicating top-down control and frontostriatal deterioration. However, the absence of group differences between non-FXTAS carriers and controls in AS and PS markers suggests saccade performance may not be a sensitive enough measure for detecting conversion to FXTAS, but instead more helpful as translational biomarkers of FXTAS progression.

Keywords: FXTAS; antisaccade; eye movements; inhibitory deficits.; prosaccade.