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

A pseudocaloric nystagmus is, in its strict sense, a spontaneous nystagmus activated by the unspecific stimulus of syringing the auditory canal. 40 patients with a unilateral, peripheral-vestibular defect were examined electronystagmographically. With most patients the 30 degrees caloric stimulation gave an incorrect result of the degree of hypoexcitability with all parameters (duration, maximum frequency and maximum intensity). This incorrect result was most pronounced with patients after neurectomy of the vestibular nerve, who frequently had a heavily reduced reaction of the healthy ear. For quantitative measurement of genuine pseudocaloric effects, by a special method of examination (as for instance by consideration of the "maximum spontaneous nystagmus"), the "real" vestibular excitability was calculated. Data exceeding this value were regarded as genuine pseudocaloric nystagmus. At stimulation temperatures of 44 degrees to 17 degrees C they were so low as to be negligible. They were only found with 5 of the 40 patients and amounted to only 10-20% of the reaction of the healthy ear. However, with ice water there frequently were considerable pseudocaloric reactions. So testing with ice water is not appropriate.
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PMID:[Pseudocaloric nystagmus (author's transl)]. 13 67

Spontaneous and experimental vestibular activity in 84 patients after total resection of neurinomas of the acoustic nerve is analysed. In the immediate postoperative period the frequency of marked manifestations of spontaneous vestibular activity reduced sharply, but spontaneous nystagmus persisted in 97.5% of patients. In some patients spontaneous nystagmus to the side from which the tumor had been removed become more conspicuous. In the remote postoperative period spontaneous nystagmus was unilateral in 45.5% of patients, bilateral in 40.3%, and not recorded at all in 14.2% of patients. In the early postoperative period vestibular hyperreflexia was recorded in 93.7% of cases, in the remote period it was found in 76.6% of cases. Data obtained by comparing the results of caloric tests with cold and hot water in these patients are also analysed.
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PMID:[Spontaneous and experimental vestibular activity following total removal of neurinomas of the auditory nerve]. 30 20

A mathematical model is proposed to explain the induction of nystagmic eye movements in response to thermal stimulation of the ear by air and water. Laplace-transformed equations are set up to describe heat flow in the meatus lumen to the ear-drum and heat transmission into meatus wall. Heat transport to the lateral semicircular canal, resulting in convective endolymph flow, and the induction of reflectory eye movements are included in the mathematical description. Input of the model is the time-course of temperature at the irrigating tip, output is the time-course of eye position (in correspondence to experimental nystagmogramms). The predicted nystagmus is in good agreement with experimental results, thus supporting our assumptions on the thermal effects of air and water irrigations.
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PMID:A mathematical model of air and water caloric nystagmus. 31 Jun 91

Serial Thermal Vestibulometry with the application of increasing caloric stimuli (corresponding to decreasing temperature of water at successive irrigration of the ears) was performed on normal subjects and patients with lesions in the central nervous system involving the statoacoustic subsystem. The normal values and 'slope' values (i.e.increase in degrees of velocity of slow component of nystagmus in response to each 4 degrees C change in water temperature) were computed to yield values of the normal vestibulogram. The values obtained in patients were compared with those of the Normograms and the following diagnostic patterns observed: (a) Hypograms, (b) Hypergrams, (c) Central Vestibular Decruitment. Central Vestibular Recruitment has been explained on the basis of the locus of the lesion leading to involvement of the nystagmogenic area in the lower part of the reticular formation, suprasegmental neurones in the vicinity of the vestibular nuclear complex, and partial destruction of the complex itself, each being responsible alone or in combination. Hypergrams presumably result from suprasegmental lesions, e.g. in cerebrum and stem components. Central decrittment follows neural lesions in the vestibular subsystem. Hypograms are found in vestibular nuclear pathology. Furthermore, it helps in charting a plan for therapy, viz. head and balance exercise, in particular, in the sense that his exercise is not helpful in cases with central decruitment but is in peripheral one. An explanation for this has been put forward.
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PMID:Vestibular recruitment and decruitment. 31 50

Most of the previous literature concerning otologic problems in compressed gas environments has emphasized middle ear barotrauma. With recent increases in commercial, military, and sport diving to deeper depths, inner ear disturbances during these exposures have been noted more frequently. Studies of inner ear physiology and pathology during diving indicate that the causes and treatment of these problems differ depending upon the phase and type of diving. Humans exposed to simulated depths of up to 305 meters without barotrauma or decompression sickness develop transient, conductive hearing losses with no audiometric evidence of cochlear dysfunction. Transient vertigo and nystagmus during diving have been noted with caloric stimulation, resulting from the unequal entry of cold water into the external auditory canals, and with asymmetric middle ear pressure equilibration during ascent and descent (alternobaric vertigo). Equilibrium disturbances noted with nitrogen narcosis, oxygen toxicity, hypercarbia, or hypoxia appear primarily related to the effects of these conditions upon the central nervous system and not to specific vestibular end-organ dysfunction. Compression of humans in helium-oxygen at depths greater than 152.4 meters results in transient symptoms of tremor, dizziness, and nausea plus decrements in postural equilibrium and psychomotor performance, the high pressure nervous syndrome. Vestibular function studies during these conditions indicate that these problems are due to central dysfunction and not to vestibular end-organ dysfunction. Persistent inner ear injuries have been noted during several phases of diving: 1) Such injuries during compression (inner ear barotrauma) have been related to round window ruptures occurring with straining, or a Valsalva's maneuver during inadequate middle ear pressure equilibration. Divers who develop cochlear and/or vestibular symptoms during shallow diving in which decompression sickness is unlikely or during compression in deeper diving, should be placed on bed rest with head elevation and avoidance of maneuvers which result in increased cerebrospinal fluid and intralabyrinthine pressure. With no improvement in symptoms after 48 hours, exploratory tympanotomy and repair of a possible labyrinthine window fistula should be considered. Recompression therapy is contraindicated in these cases...
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PMID:Diving injuries to the inner ear. 40 82

Pursuing the problem whether and why the pneumatization of mastoid bone has any influence on caloric nystagmus, we examined 15 large or extensively (L.P.) and 15 poorly (P.P.) pneumatized subjects. Following water irrigation (44 degrees and 30 degrees C, 30 sec) we checked the parameters maximum SPV, max. frequency, latency, duration and time of max. response by ENG recordings. Both groups differed significantly for all parameters except duration (p less than 0.001). On comparing these findings with an earlier proposed model (Bock & Bromm, 1977) we could show a good correspondence for the P.P. group by doubling the parameter 'thermal diffusivity of mastoid bone'. An even better correspondence could be found by diminishing the parameter 'coefficient of temperature changes by perfusion'. The theoretical and practical implications and conclusions of our findings are discussed.
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PMID:The influence of pneumatization of mastoid bone on caloric nystagmus response. A clinical study and a mathematical model. 47 8

After caloric stimulation with water at 30 degrees C for 30 sec an electronystagmogram (ENG) was registered. Simultaneously with the ENG the test person's nystagmus was observed by Frenzel's glasses. If the evaluation is limited to the frequency of the nystagmus and if it is possible to neglect the velocity of the slow phase, the simple observation through Frenzel's glasses and its plotting on a time chart recorder is no less effective than an ENG for measuring the difference between the right and left labyrinth.
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PMID:Caloric nystagmus: ENG in comparison with observation by Frenzel's glasses. 48 46

On the basis of our own experiences and the current literature, the following guidelines were established for the evaluation of scubadivers: 1. The ENT physical examination must include otoscopy and the valsalva manoeuver. The scubadiver should be able to promptly and symmetrically inflate his middle ear spaces. A central perforation is a relative contraindication, while a marginal ear drum perforation is an absolute contraindication for scubadiving. 2. Recommendations to the diver: Ear pressure equalibration should be performed continuously with increasing and decreasing water depth. Ear plugs should never be used. 3. Management of diving injuries: Barotitis should be treated in a manner similar to acute otitis media. Transient vertigo while ascending (alternobaric vertigo) without nystagmus or hearing impairment needs no further vestibular examination. A middle ear exploration is indicated when there is suspicion of a perilymphatic fistula.
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PMID:[Middle and inner ear barotrauma caused by scubadiving (author's transl)]. 52 29

An electro-nystagmographic study of postural effects on the nystagmus response has been performed in 40 patients with adolescent idiopathic scoliosis aged from 10 to 16 years. The control group comprised 29 healthy children of the same age. Caloric labyrinthine stimulation was done in the supine and erect position. The results were analysed with the aim of finding out whether an increased scoliotic deformity might influence the labyrinthine response. For comparison of the nystagmus response in the two different positions a quotient of the values (degrees/second) obtained from cold water stimulation in the erect and supine position was calculated. In the control children the labyrinthine response in erect posture was half of the response in supine posture. In erect posture the scoliotic deformity increased. This obvious change in the spine did not increase the caloric response from the convex side labyrinth. The predominance of the convex side labyrinth observed in the supine position was thus not seen in the erect position. The results of this study did not support the assumption that a postural deformity in the spine can influence a calorically induced labyrinthine response.
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PMID:Postural effects on nystagmus response during caloric labyrinthine stimulation in patients with adolescent idiopathic scoliosis. II. An electro-nystagmographic study. 53 84

A new air caloric testing method is described in which the temperature of a continuous aural irrigation is switched hot and cold values at times calculated to control the intensity of the resulting vestibular stimulation. Applications of low or high caloric stimulus intensities to normal subjects were well tolerated and reliably produced appropriate low or high intensity nystagmic responses. Nystagmus intensity values obtained from this study were compared with predicted intensity values from a computerized simulation of the actual test conditions, and also with values obtained when using biphasic water irrigations. As a result, further improvements in our methodology have been effected.
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PMID:Results of new air caloric testing method among normal subjects. I. Biphasic testing. 64 96


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