Gaze Holding in Humans Clinical Trial
Official title:
Verticality Perception and Gaze Holding in Healthy Human Subjects and Patients With Acute and Chronic Cerebellar Disorders
The long-term goal of this research is to advance the investigators knowledge of how the
cerebellum a) controls gaze holding and compensates for impaired gaze stability and b)
modulates vestibular information that is forward-ed from the labyrinth and brought to
perception. While gaze holding is stable also at large angles of gaze eccentricity in healthy
human subjects, patients with chronic (degenerative) cerebellar disorders are inable to
stabilize gaze in eccentric positions, resulting in eye drift towards primary
(straight-ahead) position and com-pensatory gaze-evoked nystagmus. When returning to primary
position, a compensatory nystagmus into the opposite direction (called rebound nystagmus) can
be observed in these patients. Unlike patients with de-generative cerebellar disorders,
patients suffering from ischemic of hemorrhagic stroke within the cerebellum present with
acute deficits of gaze holding and verticality perception.
While a linear relationship between the amount of eye velocity drift and eccentricity of eye
position has been proposed in healthy human subjects, others suggested non-linear behaviour.
The strategy of this research is to characterize gaze holding and verticality perception in
healthy human subjects and patients with either acute (ischemic or hemorrhagic) or chronic
degenerative cerebellar disorders and to relate eye movement findings with structural imaging
of the cerebellum. The investigators will therefore analyze key cerebellar structures with
regards to loss of volume and relate these imaging findings with the participants' ability to
hold gaze and es-timate direction of vertical. The investigators hypothesize that besides the
flocculus other vestibulo-cerebellar structures are involved in gaze holding and verticality
perception in humans.
n/a