Eye Movement Abnormalities in Neurodegenerative Diseases

Abstract

Neurodegenerative disorders consist in heterogeneous group of neurological conditions characterized by a wide spectrum of clinical features resulting from a progressive involvement of distinct neuron populations. Oculomotor abnormalities take a key place in the clinical picture of these disorders because the neurodegenerative processes involve the brain circuits of eye movements. The most common abnormalities include the saccadic dysfunction, fixation instability, and abnormal smooth pursuit. The clinical assessment of oculomotor function can help to differentiate diagnosis, while electrophysiological measures provide useful biomarkers for the understanding of disease physiopathology and progression. In this chapter, we review the state of the art of the eye movement’s deficits in some neurodegenerative diseases, such as Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis, Huntington’s disease, and the hereditary ataxias.