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

This paper describes a new method and apparatus to induce nystagmus. Flow of fluid into the ear to induce nystagmus is eliminated by utilization of a closed-flow system. A probe adapted for insertion to a standardized depth into the ear, provides a flow-through path for nystagmus-inducing liquid while expanding in response to the pressurized liquid to conform to the contours of the external auditory canal and tympanic membrane. Thermal conductivity through the membrane-like probe material permits heat exchange between the flowing liquid, and the external auditory canal and/or tympanic membrane to induce nystagmus.At this time, the authors can state only that the quality of nystagmus produced is similar to that produced by current conventional methods. In the small number of patients tested, discomfort appeared to be almost negligible. The system appears to be a promising improvement dependent on the establishment of accurate parameters for diagnosis.
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PMID:A closed-flow water caloric system. 87 73

Administering intravenous sedation in conjunction with intraoperative monitoring to cataract surgery patients is a widely accepted technique. Numerous articles report local sedation techniques for cataract surgery that are, in essence, abbreviated general anesthetic techniques for insertion of the retrobulbar block (RBB). Because of variations in levels of consciousness, a number of complications have been encountered with this specific patient population, ie, movement upon insertion of the RBB, intraoperative patient movement, confusion, hypotension, respiratory depression, and respiratory arrest. In an attempt to meet the specific needs of this patient population, a study comparing propofol-fentanyl with midazolam-fentanyl was initiated. Seventy-five (ASA 1 to 3) patients were randomly assigned to two groups: propofol-fentanyl (P/F) or midazolam-fentanyl (M/F). The mean age of patients in the P/F group was 71.1 +/- 13 SD, and the mean age in the M/F group was 74.4 +/- 8.8 SD. All patients entered the operating room unpremedicated. Before the RBB, patients in both groups were given a single intravenous dose of 50 micrograms fentanyl. Propofol (mean dose, 24.7 mg) or midazolam (mean dose, 1.58 mg) was then titrated to slurred speech or nystagmus. Patients' responses to the RBB were evaluated and recorded by an objective observer. The amnestic properties of both agents were evaluated by patient questioning at 10 minutes and 24 hours. Levels of discomfort were evaluated on a scale of 1 to 5, with 1 being extremely uncomfortable and 5 being noticeable without pain. Respiratory depressant effects of both techniques was assessed via continuous pulse oximetry. Results were analyzed using the chi 2 test, rank t test, and SD.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Propofol-fentanyl versus midazolam-fentanyl: a comparative study of local sedation techniques for cataract surgery. 147 88

Treatment of a patient with otologic symptoms and associated migraine-like headache presents the otolaryngologist with formidable problems. Although clinical practice and scientific publications recognize their frequent association, relationships have yet to be well defined. This study seeks to add order to disarray by delineating symptoms and signs of a clearly identified group of migraine patients. Fifty patients with well-defined basilar migraine underwent a thorough neurotologic examination, as well as comprehensive auditory and vestibular testing. Patients were selected from 5880 patients seen over a 2-year period and were prospectively entered into the study after detailed questionnaires and testing were completed for each patient. The most common symptoms found were dysequilibrium, phonophobia, and head pressure. The most common signs were positional nystagmus, low-frequency hearing loss, abnormal loudness discomfort level, and an abnormality on caloric examination. Advanced vestibular testing showed abnormal amplitude scaling, abnormal toes-down pertubation, and an abnormal sway (condition 6) on dynamic posturography. There was frequently an asymmetry on computerized rotation. The author concludes that the majority of patients have subtle findings on testing, but a few have severe peripheral injury due to the basilar migraine. Findings are consistent with the theory that basilar migraine is a central nervous system maladaptation syndrome which creates otoneurologic symptoms and, in a small percentage of cases, may injure the peripheral end-organ.
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PMID:Neurotologic findings in basilar migraine. 198 61

Eight epileptic patients receiving anticonvulsants had recurrent visual disturbances in the form of diplopia and oscillopsia in the horizontal or vertical planes. The symptoms could be ascribed to impaired vergence mechanisms, vertical nystagmus, or abnormalities of the vestibulo-ocular reflex. Other eye movements, such as pursuit and gaze-holding, were also affected, but did not lead to complaints. Episodes of visual disturbance were often preceded by prodromes of ocular or systemic discomfort, after which oscillopsia or diplopia evolve rapidly. The symptomatology was stereotyped but unique for each patient and may reflect idiosyncratic susceptibility to the ocular motor side effects of anticonvulsants. Six of the 8 patients were taking carbamazepine and phenytoin in combination, which have similar effects on the ocular motor system.
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PMID:The characteristics and mechanisms of visual disturbance associated with anticonvulsant therapy. 233 Jan 6

A prospective neuro-otological study concerning 30 cases of fibrositis syndrome (psychogenic rheumatism, PR) and 30 age-matched normal controls was made and a retrospective study concerning 33 cases of Meniere's disease (MD) diagnosed and followed-up, examined between 1965 and 1982. Results showed: sensorineural hearing loss at low frequencies in all early stages of MD and in 10/30 of PR; hyperacusis (pain threshold below 100 dBHL bilaterally for all frequencies) without other sign of recruitment in 73.3% of PR and in 3/4 cases of MD where it was measured (discomfort or vertigo due to noise was noted retrospectively in 16/33 of early stages of MD); hyperreactivity of per-rotatory nystagmus in 53.3% of PR without neurological or peripheral vestibular lesions and, with or without vestibular unilateral lesions, in 39.9% of MD. None of the controls showed hyperacusis, hyperreactivity of per-rotatory nystagmus or deafness at low frequencies.
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PMID:Meniere's disease and fibrositis syndrome (psychogenic rheumatism). Relationship in audiometric and nystagmographic results. 659 16

Much can be learned about the brain's function in pain processing through electrical stimulation. The spinothalamic tract which is conceived to be the chief pathway for nociceptive pain and whose interruption induces dissociated sensory loss can be recognized from the anterolateral columns of the spinal cord to the posterior thalamus by the induction of feelings of chiefly contralateral, somatotopographically organized, warm, cool, or cold sensations, less often burning and rarely pain. The spinoreticulothalamic tract, whose function in normal pain processing is controversial and whose interruption produces no clinically detectable sensory loss, is normally silent to stimulation. However, in patients with deafferentation pain, it appears to become sensitive to electrical stimulation, both in the anterolateral columns and in midbrain and medial thalamus, giving rise to chiefly contralateral, non-somatotopographically organized, burning or painful sensations which often reproduce fairly accurately the patient's pain. This phenomenon, which does not appear to occur in patients with nociceptive pain, may reflect denervation neuronal hypersensitivity which is a possible pathophysiological mechanism explaining deafferentation pain. The dorsal column/lemniscal system can be recognized by electrical stimulation from the spinal cord to the somatosensory cortex by the induction of paraesthesiae. Its chronic stimulation at the level of the dorsal column, the ventrocaudal nucleus or the internal capsule appears capable of suppressing deafferentation pain. The arc of neuronal tissue extending from the septal area through hypothalamus and periventricular grey to the periaqueductal grey, which acts as a receptor area for opiates and endorphins, thereby exerting an inhibitory effect on access to the spinothalamic tract, can also be exploited through chronic stimulation for the control of pain. Stimulation of the periventricular area gives rise to feelings of warmth, comfort and relaxation, of the hypothalamus, horror and autonomic effects while that of the periaqueductal grey induces discomfort, distress, anxiety and weeping, and of the septal area flushing, paraesthesiae, nausea, nystagmus and a feeling of warmth. Thus four brain systems involved in pain signalling can be recognized by electrical stimulation, one which conveys nociceptive pain to consciousness, another that suppresses it, one that may undergo denervation neuronal hypersensitivity and bring deafferentation pain into consciousness, possibly by establishing novel connectivity and one that is presumably capable of suppressing that hyperactivity.
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PMID:Identification of pain processing systems by electrical stimulation of the brain. 718 96

A new technique was designed for vestibular testing with an air caloric stimulator. With this technique, the temperature threshold necessary to induce caloric nystagmus was measured as air temperature decreased at a constant rate (from 37 degrees C). As a pilot study, an air caloric test with continuous thermal change was done at 6 different rates of decrease: 0.01, 0.03, 0.05, 0.1, 0.15 and 0.2 degrees C/s. The rate of 0.05 degrees C/s gave the smallest standard deviation for temperature threshold in normal subjects. This deviation had the narrowest normal limits of all ordinary caloric tests when the coefficient of variation was compared (standard deviation/mean x 100). No discomfort was observed during or after the air caloric test with continuous thermal change at this rate.
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PMID:Air caloric test with continuous thermal change. 812 72

Fosphenytoin (Cerebyx), is a water soluble prodrug that is rapidly and completely converted to phenytoin. This study reports the injection-site tolerance and safety of intramuscular fosphenytoin (> 10 mg/kg doses) in 60 patients requiring a phenytoin loading dose. Patients received injections at single or multiple sites with volumes ranging from 4 to 30 ml per injection site. The majority of patients had no irritation (erythema, swelling, tenderness, bruising) or complaints of discomfort related to fosphenytoin injection either after injection (95%) or at follow-up (88%). Irritation, when reported, was mild in all cases. Forty of 60 patients (67%) reported transient side effects, primarily involving the central nervous system, such as nystagmus, dizziness or ataxia, which are commonly associated with phenytoin therapy. All patients received prescribed doses; no patient had an injection(s) stopped due to intolerance or side effects. No serious adverse events occurred with intramuscular fosphenytoin. In this study, intramuscular fosphenytoin was demonstrated to be a safe and well tolerated, and in many instances, a preferable alternative to other means of phenytoin loading.
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PMID:Intramuscular fosphenytoin (Cerebyx) in patients requiring a loading dose of phenytoin. 933 83

The ophthalmic, neurologic, and neuro-ophthalmic literature over the past year have included a wide variety of interesting case reports, patient series, and reviews involving eye movement abnormalities. This review highlights some of the more important articles and how they contribute to our understanding, diagnosis, and treatment of these disorders. A few topics will receive particular emphasis. In patients with sixth nerve palsies, botulinum toxin injection of the ipsilateral medial rectus muscle has been advocated. Recent results suggest that this treatment has no beneficial effect in acute sixth nerve palsies, but it may have a role in chronic cases. Two groups of authors, each supplying retrobulbar botulinum toxin injection for patients with acquired nystagmus and debilitating oscillopsia, obtained mixed results. One group of patients was moderately satisfied, whereas in the other group, no patients elected to repeat the treatment because of side effects such as ptosis, diplopia, or discomfort from keratitis. Finally, skew deviation is becoming a more recognized cause of vertical double vision from a central or peripheral basis. Articles published recently showed that cyclodeviation may be seen in skew deviation, and that binocular cyclotorsion distinguishes this motility abnormality from a fourth nerve palsy, which exhibits monocular excyclotorsion.
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PMID:Eye movement disorders. 1016 Apr 15

The purpose of the present investigation was to determine the effect of galvanic vestibular stimulation on visuo-spatial neglect without inducing nystagmus and associated discomfort. Fourteen patients with right-hemisphere stroke with neglect were assessed with two visuo-motor tasks ("Line crossing" and "Star cancellation") on three occasions. Seven of the subjects received galvanic vestibular stimulation during the second condition (Experiment 1), whereas the other seven received stimulation during the third assessment (Experiment 2). Between-group comparisons of stimulation effects were performed by analyzing change on visuo-spatial neglect from the first to the second condition in the two experimental groups. A significantly larger effect was demonstrated on the "Line crossing" task in Experiment 1. This finding suggests a stimulation effect beyond practice/spontaneous recovery, and may provide new possibilities in rehabilitation research because the stimulation can be given without discomfort.
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PMID:Reduction of visuo-spatial neglect with vestibular galvanic stimulation. 1038 Jul 28


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