Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Visually evoked potentials (VER) were studied in 16 patients over 3 months of age with congenital or very early loss of vision in one eye. Seven patients (group I) developed an oculomotor syndrome in the sound eye characterized by jerky nystagmus in abduction, adduction fixation preference, and head-turn toward the side of the fixating eye. The other nine patients (group II) failed to develop the above-described syndrome. In group I, VER response asymmetry was found in six cases, with crossed predominance in four and direct predominance in two. The 7th patient showed a symmetric response. In group II, eight of the nine patients showed symmetric VER responses, and one showed asymmetric response with crossed predominance. Recorded VER asymmetries seem to correlate with oculomotor disturbances.
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PMID:Oculomotor disturbances and VER findings in patients with early monocular loss of vision. 336 Mar 33

Two cases of myasthenic pseudointernuclear ophthalmoplegia are reported. The diagnosis of this rare peripheral oculomotor syndrome is established on the variability of the clinical signs, their improvement by pharmacological testing, the combined impairment of convergence, the usual association of ptosis, and in some cases the presence of specific electromyographic signs. The nystagmus of the abducting eye could result from a selective damage to the tonic muscle fibres mediating fixation, the phasic fibres (performing saccades) being spared.
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PMID:[Myasthenic internuclear pseudo-ophthalmoplegia]. 664 6

Vestibular compensation for the postural and oculomotor deficits induced by unilateral labyrinthectomy is a model of post-lesional plasticity in the central nervous system. Just after the removal of one labyrinth, the deafferented, ipsilateral vestibular nucleus neurons are almost silent, and the discharge of the contralateral vestibular nucleus neurons is increased. The associated static disorders disappear in a few days, as normal activity is restored in both vestibular nuclei. In this study, we searched for traces of vestibular compensation in isolated whole brains taken from adult guinea-pigs. The electrophysiological responses evoked in control brains were compared to those evoked in brains taken from animals that had previously been labyrinthectomized. Guinea-pigs compensated for an initial labyrinthectomy within three days. In vivo, subsequent deafferentation of vestibular nucleus neurons on the intact side triggered "Bechterew's phenomenon": a new postural and oculomotor syndrome appeared, similar to the one induced by the first lesion, but directed to the newly deafferented side. These disturbances would be caused by the new imbalance between the discharges of neurons in the two vestibular nuclei triggered by the second deafferentation. Experiments were designed to search for a similar imbalance in vitro in brains taken from labyrinthectomized animals, where the intact vestibular nerve is cut during the dissection. Isolated whole brains were obtained from young guinea-pigs at various times (one to seven days) following an initial labyrinthectomy. An imbalance between the resting activities of medial vestibular nucleus neurons on both sides of the brainstem was revealed in brains taken more than three days after the lesion: their discharge was higher on the compensated, initially lesioned side than on the newly deafferented side. In some cases, an oscillatory pattern of discharge, reminiscent of the spontaneous nystagmus associated in vivo with Bechterew's syndrome, appeared in both abducens nerves. These data demonstrate that most of the changes underlying vestibular compensation persist, and can thus be investigated in the isolated whole brain preparation. Brains removed only one day after the lesion displayed normal commissural responses and symmetric spinal inputs to vestibular nucleus neurons. However, an unusually large proportion of the neurons recorded on both sides of the preparation had very irregular spontaneous discharge rates. These data suggest that the first stages of vestibular compensation might be associated with transient changes in the membrane properties of vestibular nucleus neurons. Brains taken from compensated animals displayed a significant, bilateral decrease of the inhibitory commissural responses evoked in the medial vestibular nucleus by single-shock stimulation of the contralateral vestibular nerve. The sensitivity of abducens motoneurons on the initially lesioned, compensated side to synaptic activation from the contralesional vestibular nucleus neurons was also decreased. Both changes may explain the long-term, bilateral decrease of vestibular-related reflexes observed following unilateral labyrinthectomy. Spinal inputs to vestibular nucleus neurons became progressively asymmetric: their efficacy was increased on the lesioned side and decreased on the intact one. This last modification may support a functional substitution of the deficient, vestibular-related synergies involved in gaze and posture stabilization by neck-related reflexes.
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PMID:Plastic changes underlying vestibular compensation in the guinea-pig persist in isolated, in vitro whole brain preparations. 1046 24