TRFII-9

Consequences of cerebellar oculomotor deficits on visual perception

Principle Investigator(s):

Dr. Andreas Straube, MD

Dr. Olympia Kremmyda, MD, PhD

Dr.-Ing. Thomas Eggert, PhD

Dr. Oliver Ehrt, MD

 

Objectives:

This project aims to explore the mechanisms of interaction between oculomotor and visual impairments in healthy controls and cerebellar patients. The goal is to determine optimal strategies for improving 1) vision by optical compensation of oculomotor deficits, and 2) oculomotor performance by training with appropriate visual stimuli.

Project description(s):

Subjecthistfit_a

I.)    Visual impairments induced by conjugate fixation instabilities


Instabilities of fixation occur frequently in cerebellar diseases and manifest in combinations of oculomotor drifts and small saccades (nystagmus). These conjugate movements (i.e. movements similar and synchronous in both eyes) lead to oscillopsia and decreased visual acuity. The study will investigate whether visual acuity can be restored by artificial image stabilization. More specifically, the effects of retinal target motion and position on visual acuity will be compared between healthy controls and cerebellar patients to determine whether cerebellar nystagmus affects also visual processing. These measurements involve the technical development of a graphic system which, by means of online video-oculography, controls the retinal image during slow and fast eye movements.

FarNearStim_1 VergenceResponses_1

 

II.)    Visual impairments induced by binocular misalignments

Beside conjugate fixation instabilities also deficits in binocular alignment occur frequently in cerebellar diseases. A typical sign is esophoria (i.e. a latent convergent misalignment of the eyes that manifests during monocular viewing conditions but is compensated during binocular vision). This project investigates the cerebellar esophoria in two steps: First, the evaluation of consequences of esophoria on binocular vision, and second the adaptive capabilities of disparity driven vergence. The overall goal of this project part is to investigate the therapeutic value of orthoptic training in cerebellar patients for improving binocular coordination, and the functional meaning of such improvements for binocular vision.

 

Methods:

  • Technical Systems (MCM-T)
  • Computational modeling (MCM-M)

 

Relevant publications:

Blum BM, Kirchhoff D, Bickmann A, Ehrt O, Straube A, Eggert T (2012) Heterophoria: Vergence stability and visual acuity after asymmetric saccades. J Eye Mov Res 5:1-9

Eggert T, Kapoula Z (1995) Position dependency of rapidly induced saccade disconjugacy. Vision Res. 35:3493-3503

Filippopulos F, Eggert T, Straube A (2013) Effects of cerebellar infarcts on cortical processing of saccades. J Neurol 260:805-814

Kapoula Z, Bucci MP, Eggert T, Garraud L (1997) Impairment of the binocular coordination of saccades in strabismus. Vision Res. 37:2757-2766

Kremmyda O, Kirchner H, Glasauer S, Brandt T, Jahn K, Strupp M (2012) False-positive head¬impulse test in cerebellar ataxia. Front Neurol 3:162

Straube A, Deubel H, Ditterich J, Eggert T (2001) Cerebellar lesions impair rapid saccade amplitude adaptation. Neurology 57:2105-2108

Team:

straube kremmyda Eggert
Andreas Straube    Olympia Kremmyda        Thomas Eggert

Contact:

Thomas Eggert

Address: Feodor-Lynen-Str. 19, 81377 Munich, Germany

Tel: + 49 (0) 89 4400 7 4834

Fax: + 49 (0) 89 4400 7 4801