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The relationship between disordered pursuit and vestibulo-ocular reflex suppression.
Journal of Neurology, Neurosurgery, and Psychiatry
|January 1, 1983
Summary
Smooth pursuit and vestibulo-ocular reflex suppression share similar dynamics and pathways in the central nervous system (CNS), particularly involving the cerebellum and flocculus. Impairments can be selective, highlighting distinct CNS functions.
Area of Science:
- Neuroscience
- Ophthalmology
- Neurology
Background:
- Smooth pursuit reflex and vestibulo-ocular reflex (VOR) suppression are crucial for visual stability.
- Assessing these functions aids in understanding central nervous system (CNS) integrity.
Purpose of the Study:
- To compare the performance of smooth pursuit and VOR suppression in normal subjects and CNS disease patients.
- To investigate the shared and distinct neural pathways of these two eye movement control systems.
Main Methods:
- Measured smooth pursuit eye movements using a sinusoidal laser target (up to 1 Hz, 35° peak amplitude).
- Assessed VOR suppression breakpoint using sinusoidal yaw rotation in a Barany chair and electro-oculography.
- Correlated performance in 10 normal subjects and CNS disease patients.
Main Results:
- In normal subjects, VOR suppression breakpoint velocity closely matched pursuit peak velocity across frequencies.
- Some patients showed parallel impairment of pursuit and suppression; others had selective deficits.
- Lesions of the flocculus specifically impaired both pursuit and VOR suppression.
Conclusions:
- Smooth pursuit and VOR suppression share common dynamics and neural pathways up to the cerebellum.
- The flocculus appears critical for both functions, with subsequent dissociation.
- Assessing VOR suppression offers a valuable, independent test of CNS function.