Asymmetry in Gaze-Holding Impairment in Acute Unilateral Ischemic Cerebellar Lesions Critically Depends on the Involvement of the Caudal Vermis and the Dentate Nucleus

AbstractStabilizing the eyes in space when looking at a target is provided by a brainstem/cerebellar gaze-holding network, including the flocculus/paraflocculus complex (non-human primate studies) and the caudal vermis, biventer, and inferior semilunar lobule (human studies). Previous research suggests that acute lateralized cerebellar lesions preferentially lead to gaze-evoked nystagmus (GEN) on ipsilesional gaze. Here, we further characterize the effect of unilateral cerebellar lesions on gaze-holding and hypothesize that the side-specific magnitude of gaze-holding impairment depends on the lesion location. Nine patients (age range = 31 –62 years) with acute/subacute (≤ 10 days old) MRI-confirmed unilateral cerebellar stroke were included. Horizontal gaze holding was quantified while looking at a slowly moving (0.5°/s) flashing target (gaze angle = ±40°). Asymmetry in eye-drift velocity was calculated and compared with the d ifferent MRI patterns of cerebellar lesions. Individual peak eye-drift velocities (range = 1.7–8.8°/s) occurred at the most eccentric eye positions (gaze angle = 28–38°). We found significantly asymmetric eye-drift velocity (EDV) in eight out of nine patients. The four patients with MRI-confir med involvement of the caudal vermis and the dentate nucleus all presented with ipsilesionally-predominant EDV, while in the five patients with lesions restricted to the cerebellar hemisphere, EDV was stronger on contralesional gaze in three out of fo...
Source: The Cerebellum - Category: Neurology Source Type: research