Premium
Deficits in ocular and manual tracking due to episodic ataxia type 2
Author(s) -
Engel Kevin C.,
Anderson John H.,
Gomez Christopher M.,
Soechting John F.
Publication year - 2004
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/mds.20121
Subject(s) - ataxia , smooth pursuit , audiology , tracking (education) , psychology , physical medicine and rehabilitation , cerebellar ataxia , medicine , eye movement , neuroscience , pedagogy
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. © 2004 Movement Disorder Society