Experimental and clinical data indicate that the cerebellum is involved in the pathophysiology of advanced stages of essential @entity400 (ET). The aim of this study was to determine whether a dysfunction also affects cerebellar structures involved in eye movement control. Eye movements of 14 @entity1 with ET and 11 age-matched control subjects were recorded using the scleral search-coil technique. Vestibular function was assessed by electro-oculography. Eight ET @entity1 had clinical evidence of intention @entity400 (ET(IT)); six had a predominantly postural @entity400 (ET(PT)) without intention @entity400 . ET @entity1 showed two major deficits that may indicate @entity76 : (i) an impaired smooth pursuit initiation; and (ii) pathological suppression of the vestibulo-ocular reflex (VOR) time constant by head tilts ('otolith dumping'). In the step ramp smooth pursuit paradigm, the initial eye acceleration in the first 60 ms of pursuit generation was significantly reduced in ET @entity1 , particularly in ET(IT) @entity1 , by approximately 44% (mean 23.4 degrees/s(2)) compared with that of control subjects (mean 41.3 degrees/s(2)). Subsequent steady-state pursuit velocity and sinusoidal pursuit gain (e.g. 0.4 Hz: 0.90 versus 0.78) were also significantly decreased in ET @entity1 , whereas pursuit latency was unaffected. The intention @entity400 score correlated with the pursuit deficit, e.g. ET(IT) @entity1 were significantly more affected than ET(PT) @entity1 . Gain and time constant (tau) of horizontal VOR were normal, but suppression of the VOR time constant by head tilt ('otolith dumping') was pathological in 41% of ET @entity1 , particularly in ET(IT) @entity1 . Saccades and gaze-holding function were not impaired. The deficit of pursuit initiation, its correlation with the intensity of intention @entity400 , and the pathological VOR dumping provide additional evidence of a @entity76 in the advanced stage of ET, when intention @entity400 becomes part of the clinical symptoms, and point to a common pathomechanism. The @entity51 may indicate an impairment of the caudal vermis in ET.

Eye movement abnormalities in essential XXXX may indicate @entity76 .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity51 :: ('MESH:D009461', 'Disease') :: ['oculomotor deficits'] @entity400 :: ('MESH:D014202', 'Disease') :: ['tremor'] @entity76 :: ('MESH:D002526', 'Disease') :: ['cerebellar dysfunction']
@entity400 :: (MESH:D014202,Disease) :: ['tremor']
