Brain, Vol. 124, No. 12, 2407-2416,
December 2001
© 2001 Oxford University Press
Otolith function in cerebellar ataxia due to mutations in the calcium channel gene CACNA1A
1 Reed Neurological Research Center, Department of Neurology, 2 Jules Stein Eye Institute, Department of Ophthalmology and 3 Department of Surgery, UCLA School of Medicine, Los Angeles, California, USA
Correspondence to:
Joseph L. Demer, MD, Jules Stein Eye Institute, 100 Stein Plaza, UCLA, Los Angeles, CA 90095-7002, USA E-mail: jld{at}ucla.edu
The vestibulo-ocular reflexes stabilize retinal images during head movements. While there is a wealth of information about the interaction between the cerebellum and vestibulo-ocular reflexes mediated by the semicircular canals, little is known about the role of the cerebellum in the generation of the otolith-mediated linear vestibulo-ocular reflex (LVOR). By means of transient linear acceleration of the whole body along the interaural axis, we examined the LVOR in six patients with hereditary cerebellar ataxia due to mutations of the calcium channel gene CACNA1A, five with spinocerebellar ataxia type 6 (SCA6) and one with episodic ataxia type 2 (EA-2). Six age-matched normal subjects served as controls. Using a peak acceleration of 0.5 g in combination with recording by the binocular scleral magnetic search coil method, it was possible to study the latency and sensitivity of the LVOR in the first 150 ms after motion onset. The normal LVOR showed a significant dependence on viewing distance and covaried with vergence angle, and could be enhanced by the presence of a visible target. In contrast, the LVOR of ataxic patients had normal latency but significantly decreased sensitivity that was not enhanced with visible or nearer targets despite normal vergence. Substituting for the normal smooth LVOR slow phase, ataxic patients employed catch-up saccades 150–250 ms after motion onset. These findings suggest a critical role of the cerebellum in the modulation of otolith-ocular signals that is independent of motor vergence.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. Schlenker, G. Mirabella, H. C. Goltz, P. Kessler, A. W. Blakeman, and A. M. F. Wong The Linear Vestibulo-Ocular Reflex in Patients with Skew Deviation Invest. Ophthalmol. Vis. Sci., January 1, 2009; 50(1): 168 - 174. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. T. Aw, M. J. Todd, and G. M. Halmagyi Latency and Initiation of the Human Vestibuloocular Reflex to Pulsed Galvanic Stimulation J Neurophysiol, August 1, 2006; 96(2): 925 - 930. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-r. Tian, E. Mokuno, and J. L. Demer Vestibulo-Ocular Reflex to Transient Surge Translation: Complex Geometric Response Ablated by Normal Aging J Neurophysiol, April 1, 2006; 95(4): 2042 - 2054. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. T. Aw, M. J. Todd, L. A. McGarvie, A. A. Migliaccio, and G. M. Halmagyi Effects of Unilateral Vestibular Deafferentation on the Linear Vestibulo-Ocular Reflex Evoked by Impulsive Eccentric Roll Rotation J Neurophysiol, February 1, 2003; 89(2): 969 - 978. [Abstract] [Full Text] [PDF]
|
|