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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A quantitative test of optokinetic nystagmus was proposed. Horizontal nystagmus was examined by a large rotating cylinder with vertical stripes. Nystagmus responding to the cylinder rotation with an acceleration of 2 degrees/sec2 for 90 seconds was recorded with an electronystagmograph. On the records, the number of beats, average eye-speed, and average amplitude per each 10 seconds were calculated. This method was suitable for testing the nature of optokinetic nystagmus which indicates the ability of the eyes to adapt to objects moving through the visual field. Moreover, in order to save trouble in hand-scoring of each parameter of nystagmus, computer processing of electronystagmographic data was introduced. The results were printed numerically on the teletypewriter, and displayed graphically on a cathode ray tube and X-Y recorder. By displaying measured values on the form already printed with the normal ranges, the evaluation of the results was performed readily and objectively.
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PMID:A quantitative test of optokinetic nystagmus and its data processing by computer. 105 16

The aim of this study was to investigate whether caloric nystagmus contains response components that can be attributed to a stimulation of the vertical semicircular canals. Three dimensional eye movement recordings with a dual search coil technique revealed important horizontal, vertical and torsional nystagmus components following irrigation of the external ear canal with cold water in various head positions relative to gravity. Horizontal nystagmus components, i.e. lateral semicircular canal vectors, followed a cosine function of both the pitch and yaw angle of the head relative to gravity, confirming a mainly thermovective mechanism for stimulation of the horizontal canals. Vertical and torsional nystagmus components behaved differently following left and right ear irrigations. Right-left symmetrical vectors emerged only when the vertical and torsional components were transposed into vectors of single semicircular canal directions. The intensity of these vertical semicircular canal vectors as a function of the position of the corresponding canal relative to gravity, however, excludes important thermovective mechanisms acting at the vertical canals. It remains an open question whether these vertical canal vectors represent a non-thermovective caloric stimulation of vertical canal afferents.
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PMID:Three-dimensional analysis of caloric nystagmus in the rhesus monkey. 148 61

A case of paroxysmal tinnitus and nystagmus, accompanied by facial spasm, in which neurovascular decompression was performed, is reported. The paroxysmal tinnitus and nystagmus were synchronous with each other. Horizontal nystagmus with a rotary component was found to be counterclockwise during the brief attack of tinnitus, whereas its direction became clockwise while free of tinnitus. The patient has been postoperatively relieved not only of the facial spasm, but also of the tinnitus and nystagmus. The mechanism of the occurrence of the syndrome and the significance of the neurootologic examination are discussed.
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PMID:Paroxysmal tinnitus and nystagmus accompanied by facial spasm. 396 14

A study of the brainstem of the rat during horizontal nystagmus using the quantitative 2-deoxy-D-glucose technique reflected changes in the functional activity of cell groups based on their glucose utilization rates. Horizontal nystagmus was induced by unilateral crista ampullectomy of the horizontal canal. Comparisons of glucose utilization rates were made between experimental and control groups as well as from side to side within each group. There was a decrease of the ipsilateral medial and superior vestibular nuclei with a concomitant increase in the contralateral medial vestibular nucleus when compared to control. The medial rectus motor division of the ipsilateral oculomotor nucleus showed an increase whereas the ipsilateral abducens and the ipsilateral nucleus prepositus hypoglossi exhibited a decline in their utilization rates. The extra ocular motor nuclei responsible for the excitatory fast phase of nystagmus utilizes more substrate than those involved in the slow phase. An increase was also measured in the ipsilateral lobule of the cerebellar nodulus. The lateral reticular nucleus showed a bilateral decrease in its glucose utilization rate when compared to control.
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PMID:A quantitative [14C]-2-deoxy-D-glucose study of brain stem nuclei during horizontal nystagmus induced by lesioning the lateral crista ampullaris of the rat. 405 67

Bilateral disruption, or one-sided transection of the basal optic root with a partial injury of this tract of retinal fibres on the other side, abolished vertical, but spared horizontal optokinetic head-nystagmus. Horizontal nystagmus could not be evoked when the ventral part of the pretectum was injured and the basal optic root was transected on the same side. The lesions were checked by the cobalt-filling technique. It is concluded that the basal optic nucleus mediates stimuli which evoke vertical optokinetic head-nystagmus in frogs.
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PMID:Transection of the basal optic root in the frog abolishes vertical optokinetic head-nystagmus. 660 69

Eye movements were studied quantitatively using electro-oculography in seven patients with rod monochromacy. Attention was given to eye movement abnormalities that could help to differentiate rod monochromacy from other forms of congenital nystagmus. Horizontal nystagmus in center gaze had pendular and jerk waveforms with much lower amplitude than that in patients with other forms of congenital nystagmus and visual acuity of 20/200-20/400. Slow build-up of slow component velocity over many seconds and directional asymmetry of optokinetic nystagmus (OKN) were observed during monocular optokinetic stimulation. The directional asymmetry of OKN was characterized by a higher OKN gain (eye velocity/OKN drum velocity) during rotation of the OKN drum in the temporal-to-nasal direction in the visual field, than that during drum rotation in the nasal-to temporal direction. Similar directional asymmetry and slow build-up are found in afoveate animals, such as the rabbit, during monocular optokinetic stimulation, but are not found in normal human subjects or in patients with other forms of congenital nystagmus.
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PMID:Eye movement abnormalities in rod monochromacy. 697 56

A female infant with horizontal nystagmus and normal ophthalmic examination had isolated absence of the optic chiasm on magnetic resonance imaging. Eye movements were recorded on video and reviewed. Horizontal nystagmus without see-saw nystagmus was observed. Visual evoked potential showed inter-hemispheric asymmetry compatible with the absence of crossing chiasmal fibers. Systemic abnormalities in this patient included cleft lip, preauricular skin tags, broad thumbs, and an anteriorly positioned anus, suggestive of Townes-Brock syndrome.
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PMID:Absent optic chiasm presenting with horizontal nystagmus. 2050 4

Unlike brainstem strokes, small cerebellar strokes can cause isolated dizziness/vertigo with horizontal nystagmus mimicking vestibular neuritis or direction-changing apogeotropic positional nystagmus mimicking benign paroxysmal positional vertigo. Horizontal nystagmus caused by cerebellar strokes were directed toward the side of the lesion, and enhanced when the patient lie on the non-affected side; the enhanced nystagmus were apogeotropic at this position. Direction-changing apogeotropic positional nystagmus, caused by similar cerebellar lesions, were also enhanced when the patient lie on the non-affected side. A possible mechanism of this enhancement of the two nystagmus may be a disinhibition of the otolich-ocular responses.
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PMID:[Dizziness/vertigo caused by small cerebellar/brainstem strokes]. 2227 91