Nystagmus

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nystagmus

[nə′stag·məs]
(medicine)
Involuntary oscillatory movement of the eyeballs.

Nystagmus

 

an involuntary, rapid rhythmic oscillation of the eyeballs. The bilateral form of nystagmus is much more common than the unilateral form. Nystagmus can be lateral, rotatory, vertical, or diagonal, depending on the direction of the oscillations of the eyeball. The condition need not be pathological. For example, rotatory nystagmus can be induced in healthy persons who are revolving in a swivel chair, optokinetic nystagmus can result from fixing the eyes on moving objects, and caloric nystagmus can result when cold or warm water is poured into the ear.

Nystagmus is pathological when it results from a morbid condition in the vestibulocochlear nerve, in the vestibular nuclei of the brainstem, or in the labyrinth of the vestibular apparatus. Nystagmus can also result from a morbid process in the cerebellum, an inflammation of the inner ear, cerebrocranial traumas, infections and toxicoses of the brain, or neoplasms in the brain. In rarer cases, nystagmus is caused by eye diseases. Miner’s nystagmus is an occupational disease in miners who work with a pick under poorly illuminated and poorly ventilated conditions. Because these workers are constantly looking up or to the side, certain eye muscles become strained.

Nystagmus is treated by eliminating the underlying cause. In cases of miner’s nystagmus, the worker is transferred to jobs above the ground.

REFERENCE

Tsimmerman, G. S. Klinicheskaia otonevrologiia. Moscow, 1952.

V. A. KARLOV

References in periodicals archive ?
the calibration test, the test for gaze nystagmus, the test for spontaneous nystagmus as well as positional tests are also documented by the computerised ENG machine.
The central vestibular signs observed in the 32 patients included 14 cases (8.5% of the entire study group) of dissociated nystagmus (which was always associated with one or more other central signs), 5 cases (3.0%) of bidirectional semi-spontaneous nystagmus, 4 cases (2.4%) of vestibular decruitment (torsion swing responses smaller in amplitude than caloric responses, 3 cases (1.8%) of semi-spontaneous nystagmus in different directions of the gaze, 3 cases of spontaneous nystagmus that did not influence the torsion swing and caloric tests, 2 cases (1.2%) of vertical spontaneous nystagmus, 2 cases of alternating spontaneous nystagmus, and 1 case each (0.6%) of absent fixation effect with eyes open, perverted nystagmus, and inverted nystagmus.
The patients' subjective ratings and the physicians' global impressions of change were strongly supported by the objective findings from clinical neurootological examinations: swaying in the Romberg test and rotation in Unterberger's stepping test were decreased considerably and spontaneous nystagmus was no longer found in half of the patients who had nystagmus before treatment.
In the infant that has poor or absent behavioural visual responsiveness without spontaneous nystagmus, and which cannot be explained by ophthalmoscopy, the differential diagnoses are delayed visual maturation, cerebral visual impairment, and saccade initiation failure (ocular motor apraxia).
The authors constructed a spike detection algorithm also usable for extraneous saccades, but since this computed the mean square error between eye movement and stimulation signals, such a procedure would not be possible for our spontaneous nystagmus without any stimulation signal.
Parkinson's Disease); (3) a medical diagnostic hypothesis of central dizziness and/ or vertigo; (4) a decrease in visual acuity, of whatever nature, that could not be corrected using lenses; and (5) the presence of the following changes in VENG: irregular calibration, spontaneous nystagmus or semi-spontaneous nystagmus with open eyes, or of congenital nystagmus with closed eyes that had an angular velocity greater than 7 degrees per second.
With the vHIT we were able to record a very low gain for head impulses towards the affected side with covert and overt refixation saccades as a response to the vestibular deficit and because of the spontaneous nystagmus beating towards the normal ear as well as anticompensatory quick eye movements for head movements towards the nonaffected side (Figure 2).
Gaze-induced nystagmus (27%) and spontaneous nystagmus (11%) [4]
The patients with history of dizziness, light-headedness, aural fullness or imbalance are subjected to thorough ENT Clinical examination, Neuro-otological tests (Head shaking test, Head-Thrust test and Spontaneous nystagmus, Dix-Hallpike test).
The investigated parameters included spontaneous nystagmus, head-shaking nystagmus, positional nystagmus during the Dix-Hallpike and head-roll maneuvers, nystagmus with the Valsalva maneuver, the Tullio phenomenon after hyperventilation and exposure to 3 kHz at 110 dB, and eye movements after mastoid vibration at 100 Hz.
On admission, clinical ear, nose, and throat examination revealed horizontal spontaneous nystagmus toward the right side (unaffected ear) with a rotational component visible with and without Frenzel glasses.
At that time, no spontaneous nystagmus was observed (with and without vision suppression), not even after head-shaking.

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