positional nystagmus


Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to positional nystagmus: rotary nystagmus, spontaneous nystagmus

nystagmus

 [nis-tag´mus]
involuntary, rapid, rhythmic movement (horizontal, vertical, rotatory, or mixed, i.e., of two types) of the eyeball. adj., adj nystag´mic.
amaurotic nystagmus nystagmus in the blind or in those with defects of central vision.
amblyopic nystagmus nystagmus due to any lesion interfering with central vision.
aural nystagmus labyrinthine nystagmus.
caloric nystagmus rotatory nystagmus in response to caloric stimuli in the ear, seen during the caloric test.
Cheyne's nystagmus a peculiar rhythmical eye movement resembling Cheyne-Stokes respiration in rhythm.
congenital nystagmus (congenital hereditary nystagmus) nystagmus usually present at birth, usually horizontal and pendular, but occasionally jerky and pendular; the nystagmus may be caused by or associated with optic atrophy, coloboma, albinism, bilateral macular lesions, congenital cataract, severe astigmatism, and glaucoma.
dissociated nystagmus that in which the movements in the two eyes are dissimilar.
end-position nystagmus that occurring only at extremes of gaze.
fixation nystagmus that occurring only on gazing fixedly at an object.
gaze nystagmus nystagmus made apparent by looking to the right or to the left.
labyrinthine nystagmus vestibular nystagmus due to labyrinthine disturbance.
latent nystagmus that occurring only when one eye is covered.
lateral nystagmus involuntary horizontal movement of the eyes.
optokinetic nystagmus nystagmus induced by looking at objects moving across the visual field.
pendular nystagmus nystagmus in which the oscillations of the eyes have an equal rate, amplitude, direction, and type of movement.
positional nystagmus that which occurs, or is altered in form or intensity, on assumption of certain positions of the head.
retraction nystagmus (nystagmus retracto´rius) a spasmodic backward movement of the eyeball occurring on attempts to move the eye; a sign of midbrain disease.
rotatory nystagmus involuntary rotation of the eyes about the visual axis.
secondary nystagmus nystagmus occurring after the abrupt cessation of rotation of the head, caused by the labyrinthine fluid continuing to move.
spontaneous nystagmus that occurring without specific stimulation of the vestibular system.
vertical nystagmus involuntary up-and-down movement of the eyes.
vestibular nystagmus nystagmus due to disturbance of the labyrinth or of the vestibular nuclei; the movements are usually jerky.

po·si·tion·al nys·tag·mus

nystagmus occurring only when the head is in a particular position.

po·si·tion·al nys·tag·mus

(pŏ-zish'ŏn-ăl nis-tag'mŭs)
Ocular disorder occurring only when the head is in a particular position.
References in periodicals archive ?
Aw ST, Todd MJ, Aw GE, McGarvie LA, Halmagyi GM, 2005, Benign positional nystagmus. A study of its three-dimensional spatiotemporal characteristics.
[9], the indication for ET in case of SHL is progressive hearing loss, acute hearing loss with vertigo, acute hearing loss with the presence of positional nystagmus in a spinal position, or unresponsiveness to CS therapy.
Persistent positional nystagmus and positional nystagmus (12 [right arrow] 28%) [2, 34]
Nystagmus was persistent, one-directional and pluri-positional during bedside examination, while paroxysmal positional nystagmus was not evoked.
(2,12) ENG may detect directional preponderance, reduced caloric response, spontaneous nystagmus, positional nystagmus, or no abnormalities at all.
Electronystagmography revealed no spontaneous or positional nystagmus. The alternate binaural bithermal test revealed a 68% reduced vestibular response (RVR) on the right with no significant directional preponderance, and the simultaneous binaural bithermal test showed a type 2 response, confirming the RVR on the right.
The typical history of BPPV and the characteristic torsional positional nystagmus were identified in all patients.
Electronystagmography (ENG) elicited no spontaneous or positional nystagmus; there was ocular fixation suppression of calorically induced nystagmus.
No spontaneous or positional nystagmus was evident on electronystagmography.
Electronystagmography elicited no spontaneous or positional nystagmus. The alternate binauralbithermal stimulus yielded a 35% reduced vestibular response left and a 29% directional preponderance right.