Horizontal and vertical smooth pursuit was compared with otolith-ocular responses in 11 @entity1 with @entity6447 and 21 normal subjects using three-dimensional magnetic search coil eye movement recordings. Otolith-ocular responses were investigated during off-vertical @entity717 . This stimulus induces nystagmus consisting of the exponentially decaying canalicular response, and an eye-velocity modulation and offset which arise from the excitation of the otoliths by the gravity vector, which lasts as long as the rotation continues. Otolith-ocular reflexes are intimately interrelated with visual tracking when real targets are viewed during linear motion. The responses of both the translational vestibulo-ocular reflex and the pursuit system have been shown to be linearly dependent on the inverse of the viewing distance, so that a common central pathway for the two systems has been suggested, probably travelling through the cerebellum. Thus, the aim of the study was to evaluate to what extent these reflexes are disturbed in @entity76 . The results confirm the earlier notion that in normal subjects pursuit performance is better for horizontal than for vertical tracking, and that it is better for upward than for downward tracking. This pattern is also found in @entity1 . In addition, smooth pursuit performance is clearly degraded in @entity1 , but the modulation of eye-velocity during off-vertical @entity717 is enhanced. Since the amount of this enhancement does not correlate with the amount of pursuit impairment, degradation of smooth pursuit and pathological enhancement of otolith-ocular responses seem to be independent effects of @entity2746 . Thus, the increase in the otolith-ocular response in @entity1 cannot be attributed to adaptational mechanisms trying to overcome the smooth pursuit deficiency; it is more likely to represent pathological disinhibition of otolith derived responses. The absence of compensatory eye-velocity offset during off-vertical @entity717 may reflect the fact that in @entity1 the otolith signals are not utilized in computations thought to be important for spatial orientation mechanisms arising from the interaction of vestibular, @entity227 signals.

Smooth pursuit eye movements and otolith-ocular responses are differently impaired in XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity227 :: ('MESH:D014786', 'Disease') :: ['visual and somatosensory'] @entity76 :: ('MESH:D002526', 'Disease') :: ['cerebellar disease'] @entity6447 :: ('MESH:D002524', 'Disease') :: ['cerebellar ataxia'] @entity717 :: ('MESH:D009069', 'Disease') :: ['axis rotation'] @entity2746 :: ('MESH:D013132', 'Disease') :: ['cerebellar degeneration']
@entity6447 :: (MESH:D002524,Disease) :: ['cerebellar ataxia']
