Saccades: A window to the brain in Parkinson’s Disease

  • Shaila Gunn UBC

Abstract

Saccades are a high velocity eye movement that function to move the fovea to a new visual target. The complex processing of a saccade involves many cortical and subcortical brain regions. The brain regions involved in a saccade will differ depending on whether the shift in gaze is voluntary or driven by a visual stimulus. The complex neuroanatomy of saccades leads to saccadic dysfunction in a number of neurological disorders, such as Parkinson ’s disease (PD). PD patients experience hypometric saccades with increased latency, often requiring the use of multistep saccades to reach a visual target. They also have an increased proportion of involuntary express saccades. These pathological consequences can be studied by understanding the brain areas involved in the generation of a saccades as well as the areas that are affected in PD. In this way, saccadic eye movements can be viewed as a window into the brain, allowing their use to understand what structures are damaged simply by looking at an eye movement. Saccadometry, the study of saccades, can be used as a clinical tool in the PD population in the differential diagnosis and staging of PD, as well as evaluating the effects of treatments such as L-dopa or deep brain stimulation of the subthalamic nucleus on the disease. It can also allow us to understand where these treatments are working, by how they change saccades.

Published
2020-08-24
Section
Reviews