The functional status of the velocity storage mechanism was studied in patients at long-term follow-up (2 to 4 years) after unilateral vestibular neurectomy. The time constant of the vestibulo-ocular reflex (VORtc), the effect of head tilt on postrotatory nystagmus, optokinetic after-nystagmus (OKAN), and nystagmus after rapid head shaking were studied in 10 patients. In agreement with previous...

PURPOSE To use the suppression of optokinetic nystagmus (OKN) as an objective measure of subjects' ability to distribute their visual attention to different elements-static or dynamic, simple or complex-in their visual environment. METHODS Large-field, constant-velocity projected images, along with a stationary central fixation target were presented to 25 young participants (13 women). Images...

Optokinetic nystagmus (OKN) is a fundamental gaze-stabilizing response found in almost all vertebrates, in which eye movements attempt to compensate for the optic flow caused by self-motion. It is an alternating sequence of slow compensatory eye movements made in the direction of stimulus motion and fast eye movements made predominantly in the opposite direction. The timing and amplitude of the...

BACKGROUND Reports on the impact of a loss in the central field of vision on optokinetic nystagmus (OKN) are varied. A study was therefore undertaken to reassess the role of the central retina in the generation of OKN in a large group of patients with age related macular degeneration. METHODS Four groups of 20 patients were examined: a control group without scotoma and three groups with absol...

Vestibular findings in a group of 35 patients with spasmodic torticollis without other otological or neurological symptoms were reviewed. The most consistent abnormality, present in more than 70% of cases, was a directional preponderance of vestibular nystagmus in the dark in a direction opposite to the head (chin) deviation. Rigidly clamping the head to a rotating chair did not abolish the dir...

Responsiveness to hypnotic procedures has been related to unusual eye behaviors for centuries. Kallio and collaborators claimed recently that they had found a reliable index for "the hypnotic state" through eye-tracking methods. Whether or not hypnotic responding involves a special state of consciousness has been part of a contentious debate in the field, so the potential validity of their clai...

In previous work, subjects looked at a target stabilized at the fovea, superimposed on a sinusiodally moving OKN stimulus. The stabilized target (no retinal-slip) suppressed OKN leaving residual eye movements that were often in counterphase with the OKN stimulus motion. In the present study we explored how this type of suppression of OKN is influenced by OKN stimulus predictability: OKN stimulu...