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Ocular motor abnormalities in ataxia telangiectasia
R F Lewis1, H M Lederman, T O Crawford
1Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Annals of Neurology
|September 11, 1999
Summary
Ataxia telangiectasia causes significant oculomotor dysfunction, affecting image stabilization and gaze shifting. This study details these eye movement abnormalities in a large patient cohort.
Area of Science:
- Neurology
- Ophthalmology
- Genetics
Background:
- Ataxia telangiectasia (AT) is a rare genetic disorder.
- Oculomotor dysfunction is a known feature of AT.
- Previous studies reported on small patient groups.
Purpose of the Study:
- To comprehensively characterize oculomotor abnormalities in ataxia telangiectasia.
- To investigate the range of eye movement deficits in AT patients.
Main Methods:
- Clinical examination of eye movements in 56 AT patients.
- Electrooculographic recordings in 33 AT subjects.
- Assessment of image stabilization and gaze shifting systems.
Main Results:
- Deficits in pursuit, gaze holding, convergence, and vestibular/optokinetic responses.
- Abnormal saccades (latency, amplitude) and impaired fixation.
- Reduced vestibular and optokinetic quick phases observed.
Conclusions:
- Oculomotor dysfunction in AT involves both image stabilization and gaze shifting.
- Cerebellar flocculus/paraflocculus likely involved in stabilization deficits.
- Superior colliculus control dysfunction may underlie saccade/fixation issues.