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

Warm air caloric stimulation in an ear with tympanic membrane perforation or mastoidectomy cavity often causes contralateral nystagmus. Secondary nystagmus is common. Our evidence with squirrel monkeys and patients indicates that the primary "inversion" results from endolymph cooling due to evaporative cooling due to evaporative cooling of the mucus lining the middle ear cavity, by the dry air stimulus. Disconjugate horizontal nystagmus was found in a patient with large eardrum perforation, after cold air caloric stimulation. The effect probably resulted from stimulation of the anterior or posterior vertical semicircular canal. Inverted or disconjugate caloric nystagmus after air stimulation is much more frequently due to tympanic membrane perforation, or moisture in the external ear, than to central nervous system disease.
 ...
PMID:Air caloric stimulation with tympanic membrane perforation. 9 78

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.
 ...
PMID:Three-dimensional analysis of caloric nystagmus in the rhesus monkey. 148 61

It is well known that inverted caloric nystagmus is seen during air caloric testing in cases of chronic otitis media. The mechanism of inversion and its clinical significance are discussed here. Temperature changes in the tympanic cavity and external ear canal were measured with a microthermister and a digital tester in seventeen ears with tympanic membrane perforation, during bithermal air caloric testing. The tympanic cavity mucosa was cooled by hot stimulation because of the evaporation of heat. When the perforation was closed or humidified air was used, the tympanic cavity mucosa was not cooled by hot stimulation and the inverted caloric nystagmus changed to a normal response. Inverted caloric nystagmus occurred in 30.4% of 335 ears affected by chronic otitis media with perforation. Inverted caloric nystagmus occurred in 90 ears with hot stimulation and in 12 ears with cold stimulation. Inverted caloric nystagmus turned to normal response after myringoplasty in all of 10 ears. The cooling effect caused by evaporation of water from the moist middle ear mucosa during dry air blowing and direct thermal conduction to the vestibulum through a perforation of the ear drum and inversion of the endolymphatic convection seemed to cause the inversion.
 ...
PMID:[Inverted caloric nystagmus of perforated ears upon air caloric stimulation]. 204 Sep 15

Two patients with sudden progressive profound hearing loss resulting from Ramsay Hunt syndrome are reported. Case 1: A 63-year-old woman was admitted to Jichi Medical School Hospital with sudden, progressing deafness of the left ear, vertigo, sore throat, and hoarseness. An otoscopic examination revealed the external ear and the tympanic membrane to be normal. Pure-tone audiometry revealed profound deafness in the left ear. A horizontal nystagmus in the non-affected direction was observed by gaze nystagmus test. An endoscopic examination revealed herpetic vesicles and shallow ulcers on the left side of the pharynx and the larynx. There was complete paralysis of the left recurrent nerve. Hearing acuity of the left ear did not recover at all with steroid hormone therapy. Case 2: A 75-year-old man was referred to the ENT Clinic by a dermatologist for hearing evaluation in Ramsay Hunt syndrome. The man had noticed severe otalgia and sudden progressive deafness of the right ear approximately 2 weeks prior to admission. Physical examination revealed herpetic vesicles and ulcers in the right external ear and lateral neck. Complete paralysis of the right facial nerve was noted. Profound hearing loss in the affected ear was observed by pure-tone audiometry. A gaze nystagmus test revealed a horizontal nystagmus in the non-affected direction. No recovery of the cochlear function was noted following administration of antiviral drug. The pertinent literature is briefly reviewed.
 ...
PMID:Acute profound deafness in Ramsay Hunt syndrome. Two case reports. 285 31

Vestibular function tests were performed on a series of 57 children between the ages of 1 and 16 years. Inattention and immaturity of eye movement control created difficulties in the analysis of the electronystagmography traces in some instances. With the eyes closed, spontaneous and positional nystagmus occurred in 20% of asymptomatic children and this was thought to be physiological. Changes in external ear pressure (fistula test) enhanced this spontaneous nystagmus. Smooth pursuit ataxia and optokinetic abnormalities were common in the children with reading disabilities and those with congenital deafness, and were thought to be soft neurological signs of brainstem dysfunction. The torsion swing chair test was acceptable and gave easily readable responses. Caloric abnormalities were very common in children with reading disabilities and provided useful information in those with congenital and acquired disorders of hearing and balance. It was concluded that normal data were required for children of all ages in order to improve our understanding of electronystagmography in children.
 ...
PMID:Vestibular function tests in children. 687 45

Six cases of the CHARGE association are described that were encountered consecutively at an institute for the deaf. Five of them showed external ear anomalies and according to expectations all of them showed some degree of hearing impairment: two had moderate mixed hearing loss; three had severe to profound sensorineural hearing loss; and one was completely deaf. In addition, they all had vestibular areflexia and the five cases examined with computer tomography of the petrosal bones showed aplasia of the semicircular canals. One case with poor visual acuity also showed subnormal optokinetic responses and horizontal pendular nystagmus during visual fixation. All these children were initially diagnosed as having severe psychomotor retardation, because of their failure to acquire speech and their delayed motor skill development. Given the fact that (mild) mental retardation was found in only one case, the delayed development could at least in part have been caused by vestibular areflexia. The vestibular findings support previously reported temporal bone findings that indicate dysplasia or aplasia of the superior part of the labyrinth. Early detection of the full extent of (multiple) sensory deficits is necessary in children with the CHARGE association who have similar abnormalities, because aggressive intervention and special educational support are likely to be of great benefit to sensorimotor development.
 ...
PMID:Vestibular areflexia as a cause of delayed motor skill development in children with the CHARGE association. 915 48

In patients with perilymphatic fistula (PLF), nystagmus may sometimes be elicited by application of pressure to the external ear canal. The extent to which the normal population also exhibits such 'pressure sensitivity' is presently unknown. Our goal was to determine the limits of normal pressure sensitivity and to quantify the performance of the fistula test. Our subjects consisted of 13 normal controls and 7 patients with a history of pressure sensitivity who later underwent exploratory tympanotomy. We measured nystagmus prior to and following pressurization of the external ear canal. Pressure was applied manually over 60 s with a pneumatic otoscope bulb. In normal subjects, change in nystagmus between prepressure and postpressure tests ranged from -1.3 to 0.9%s. In patients, change in nystagmus greater than the 95th percentile limits of normal was not a reliable indication of PLF.
 ...
PMID:Limits of normal for pressure sensitivity in the fistula test. 939 Aug 42

Positron emission tomography (PET) was used to demonstrate temporary down-regulation of visual cortex activities associated with eye movements. The aim of the present study was to test this paradigm with visual evoked potentials (VEPs) in the visual cortex of 7 healthy human subjects during caloric nystagmus. Caloric stimulation was performed by irrigating the right or left external ear canals with 100 ml of warm water at 44 degrees C for 50 s with a head position of 60 degrees tilted backward in order to stimulate the horizontal semicircular canal. The subjects kept their eyes closed during and after caloric stimulation. For recording the VEPs, the flashlight was used for activating the visual cortex with the subject's eyes closed. In the 7 subjects, no significant difference was detected between the VEPs induced with and without caloric stimulation.
 ...
PMID:Visual-vestibular interaction--an evoked potential study in normal human subjects. 961 36

A patient with a postoperative fistula of the left posterior semicircular canal is presented. Negative pressure in the external ear canal produced upbeat-torsional nystagmus, which was recorded in three dimensions using binocular scleral search coils. The nystagmus was conjugate, without skew deviation, and its trajectory corresponded to the anatomic axis of the left posterior canal. The current study helps validate Ewald's first law in humans: the axis of nystagmus should match the anatomic axis of the semicircular canal that generated it. This law is clinically useful in diagnosing pathology of the vestibular end-organ, such as benign paroxysmal positional vertigo or the superior semicircular canal dehiscence syndrome.
 ...
PMID:Posterior semicircular canal nystagmus is conjugate and its axis is parallel to that of the canal. 1082 50

We describe the association of auricular abnormalities and cleft lip with or without cleft palate in two siblings. One sibling has postauricular pits, profound myopia, nystagmus and retinal pigment abnormalities. The second sibling was a fetus of 23 weeks gestation with severe cleft lip, cleft palate and external ear abnormalities. As this constellation of features has not been described together before, we believe this is a new syndrome.
 ...
PMID:Description of a new syndrome: auricular abnormalities and cleft lip in two sibs, in association with cleft palate and unusual opthalmological findings. 1631 5


1 2 Next >>