Slow target-directed eye movements in ataxia-telangiectasia

Richard F. Lewis, Thomas O. Crawford

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


PURPOSE. To analyze the slow eye movements that shift the direction of gaze in patients with ataxia-telangiectasia (A-T). METHODS. Eye and head movements were recorded with search coils in three patients with A-T during attempted gaze shifts, both with the head immobilized and free to move. RESULTS. Gaze shifts frequently included both saccadic and slow components. The slow movements were recorded after 42% of saccades and had an average peak velocity of 6.1 deg/sec and a mean amplitude of 2.0°. They occurred with the head stationary and moving, could be directed centripetally or centrifugally, had velocity waveforms that were relatively linear or exponential, and always moved the eyes toward the visual target. CONCLUSIONS. The slow movements appear to differ from pursuit and vestibular eye movements and are not fully explained by the various types of abnormal eye movements that can follow saccades, such as gaze-evoked nystagmus or postsaccadic drift. Their origin is uncertain, but they could represent very slow saccades, due to aberrant inhibition of burst cell activity during the saccade.

Original languageEnglish (US)
Pages (from-to)686-691
Number of pages6
JournalInvestigative Ophthalmology and Visual Science
Issue number3
StatePublished - Mar 11 2002
Externally publishedYes

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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