Deficits in ocular and manual tracking due to episodic ataxia type 2

Kevin C. Engel, John H Anderson, Christopher M. Gomez, John F. Soechting

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Four patients with a novel mutation leading to episodic ataxia type 2 were studied in a task that required them to track target motion either with the eyes or with the index finger of the right hand. The target initially moved in a straight line and then changed direction at an unpredictable time by an unpredictable amount. On the day of testing, 3 of the patients were evaluated as normal on a neurological exam, whereas the fourth was severely ataxic. Nevertheless, all 4 showed deficits in tracking behavior with common features. Ocular tracking tended to result in hypermetric saccades at longer than normal latencies. Smooth pursuit tracking was absent in 1 patient and had lower than normal gain in the others. Deficits in manual tracking showed similarities to the deficits in ocular tracking, with hypermetric compensations for changes in target direction. The similarities in the deficits in manual and ocular tracking suggest that they are subject to similar control by the cerebellar structures.

Original languageEnglish (US)
Pages (from-to)778-787
Number of pages10
JournalMovement Disorders
Issue number7
StatePublished - Jul 2004


  • Cerebellum
  • Hand movement
  • Hypermetria
  • Saccade
  • Smooth pursuit


Dive into the research topics of 'Deficits in ocular and manual tracking due to episodic ataxia type 2'. Together they form a unique fingerprint.

Cite this