Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recordings of horizontal nystagmus were obtained on 16 male subjects exposed to repeated patterns of horizontal angular acceleration, constant velocity rotation, and sudden-stop deceleration in the laboratory and in the free-fall and high-force periods of parabolic flight. Nystagmus intensity was a clear function of gravitoinertial force level: slow phase velocity and beat frequency increased during exposure to high force levels and decreased in free-fall compared to values obtained at I G. These findings indicate that the gain of the vestibulo-ocular reflex decreases in free-fall. This fact likely accounts for the disorientation and dizziness sometimes experienced by astronauts when moving their heads in the early phases of orbital flight and again after splashdown. The implications of the present findings, both for the etiology and for the treatment of space motion sickness, are discussed.
 ...
PMID:Variations in gravitoinertial force level affect the gain of the vestibulo-ocular reflex: implications for the etiology of space motion sickness. 697 38

Nystagmus after rapid head-shaking (post-headshake nystagmus) is often seen in patients with vestibulopathy. Post-headshake nystagmus is transient and is frequently associated with symptoms of dizziness, dysequilibrium, or vertigo. The phenomenon presumably reflects headshake-induced asymmetry in vestibulo-ocular reflex pathways, which persists after head-shaking stops. We postulated that the same vestibular imbalance that underlies post-headshake nystagmus might produce an equivalent in postural instability. To test this hypothesis, we investigated the effect of headshake on postural control and eye movements in patients who exhibited post-headshake nystagmus, vestibulopathy, or both. Postural instability was quantified with a dynamic platform device, whereas eye movements were recorded with electrooculography. Ten normal controls and 21 patients with a history of post-headshake nystagmus or unilateral vestibulopathy were evaluated. Subjects were tested for 20 seconds before and immediately after passive horizontal headshake (+/- 30-degree amplitude) at 2 Hz for 20 seconds. Postural stability was assessed while subjects stood with eyes closed, and the floor was modulated proportionally with sway. The difference in normalized peak-to-peak sway (equilibrium score) before and after headshake was assessed in all subjects and compared between groups. Post-headshake nystagmus was documented by electro-oculography recorded during posturography. Results for normal controls and vestibulopathic subjects without post-headshake nystagmus showed only a small transient decline in postural stability after headshake. Those with post-headshake nystagmus (regardless of caloric asymmetry) showed a robust decline in postural stability.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Nystagmus and postural instability after headshake in patients with vestibular dysfunction. 787 Apr 39

Much attention has been paid to hearing results after stapes surgery, but the risks of vestibular disturbance has not been extensively studied. Postoperative spontaneous nystagmus was measured daily at bedside by portable ENG in order to evaluate the vestibular damage from stapes surgery. Thirteen patients underwent primary stapedotomy or stapedectomy from August 1, 1992 to June 30, 1993. Nystagmus toward the operated ear was observed in 3 cases, that toward the opposite ear in 2 cases, that changing from toward the operated ear to toward the opposite ear in 2 cases, that changing from toward the opposite ear to toward the operated ear in 2 cases and no nystagmus in 4 cases. There was no relationship between duration of nystagmus and that of dizziness. Nystagmus was thought to be due to the following: i) inner ear damage by operation, ii) postoperative perilymphatic fistula, iii) floating footplate, and iv) stimulation of hair cells by high potassium ion in the perilymph due to blood flow into the inner ear.
 ...
PMID:Nystagmus measured by ENG after stapes surgery. 874 33

Vertigo and dizziness are common complaints encountered in clinical practice. The patient's history and a thorough otoneurological evaluation are essential for identifying the specific pathology behind the patient's complaints. If the patient reports an illusion of movement (vertigo), this most likely indicates an imbalance within the vestibular system. A sensation of rotatory movement together with a spontaneous nystagmus suggests a lesion involving the semicircular canals, while an illusion of linear movement indicates a disturbance of the otoliths. Nystagmus of central origin or caused by a peripheral vestibular lesion can usually be distinguished by other features in the history or on clinical examination. While peripheral vestibular lesions usually lead to a mixed horizontal-torsional or vertical-torsional nystagmus, a pure vertical or pure torsional nystagmus is always caused by a central lesion. With simple bedside tests such as head-shaking nystagmus and rapid head impulses deficits in labyrinthine function can clearly be detected. For a more thorough investigation of vestibular function at the level of individual semicircular canals and the otoliths, modern techniques are now available such as three-dimensional eye movement vector analysis for the evaluation of individual semicircular canal function, measurement of the subjective visual vertical for utricular, and click-evoked myogenic potentials for saccular testing.
 ...
PMID:Assessing vestibular function: which tests, when? 1089 64

Typical Paroxysmal Positional Nystagmus (PPNy) is a highly specific clinical finding that indicates the existence of a specific peripheral lesion: Paroxysmal Positional Vertigo (PPV). However, besides this typical nystagmus of high topodiagnostic significance, atypical PPNy's are also frequently found. Such atypical findings can lead one to suspect a central vestibular system pathology and often require additional diagnostic testing. Of 1805 patients with complaints of vertigo, 305 proved affected by PPV. The present study evaluated how patients affected by the posterior semicircular canal PPV (278/305, 91.2%) responded to canalith repositioning maneuvers. In 246 patients (88.5%) the Semont maneuver was performed as simplified by Toupet, while the remaining 32 subjects (11.5%) were treated with the Epley maneuver as modified by Herdman. The Semont maneuver provides the relief of symptoms in 96% of patients while the Epley maneuver resolved 78% of cases. The patients that did not respond to the maneuvers, even after several attempts, were subsequently treated using "habituation"-based rehabilitation techniques (the Brandt-Daroff technique and Vestibular Habituation Training). The presence of atypical PPNy was found in 57 subjects. Of these, the liberatory maneuver always resolved the PPV. In the present study, the choice to perform a neuroradiological study was based on the lack of response to physical therapy, whether performed with liberatory maneuvers or with habituation techniques. In 2 of the 3 cases of PPV which remained unchanged despite treatment, imaging revealed a severe expansive CNS pathology. In these patients the dizziness complaints disappeared after neurosurgery: this fact appears to confirm the central origin of these PPNy cases. These data clearly indicate that the results of PPV treatment must be carefully evaluated. In cases of PPV of the PSC, when either typical or atypical PPNy persists one month after diagnosis, with no appreciable period of remission, neuroradiological tests should be performed in order to rule out any CNS pathology.
 ...
PMID:[Therapeutic maneuvers in the treatment of paroxysmal positional vertigo: can they indicate a central genesis?]. 1206 74

A 50 year old woman experienced an episode of vertigo and nystagmus about 10 minutes after receiving her first treatment with acupuncture for shoulder pain. The nystagmus was confirmed by several health professionals. She had no previous history of nystagmus, and the symptom was not associated with feelings of faintness. Her blood pressure was 90/50 at the onset of symptoms but returned to normal while the symptoms continued. She recovered spontaneously after about five hours. Nystagmus after acupuncture has not been unequivocally reported before, though dizziness associated with hypotension is common. In this case the association may be coincidental, or a focal neurological response to needling; if the latter, then it should be regarded as an unavoidable idiosyncratic reaction.
 ...
PMID:Nystagmus following acupuncture--a case report. 1661 47

Dizziness is one of the most common reasons patients visit their physicians. Balance control depends on receiving afferent sensory information from several sensory systems: vestibular, optical and proprioceptive. Bioelectric signals, generated by body movements in the semicircular canals and in the otolithic apparatus, are transported via the vestibular nerve to the vestibular nucleus. All four vestibular nuclei, located bilaterally in medial longitudinal fasciculus, are linked with central nervous system structures. These central nervous system structures are involved in maintaining visual stability, spatial orientation and balance control. Nystagmus is a result of afferent signals balance disorders. Nystagmus due to peripheral lesions is conjugate nystagmus, because there is a bilateral central connection. Lesions above the vestibular nuclei induce deficits in synchronization and conjugation of eye movements, thus the nystagmus is dissociated. This paper shows that in peripheral vestibular disorders spontaneous nystagmus is rhythmic, associated, horizontal-rotatory or horizontal, with subjective sensation of dizziness which decreases with time and harmonic signs whose direction coincides with the slow phase of nystagmus and it is associated with mild disorders during pendular stimulation with statistically significant vestibular hypofunction. Spontaneous nystagmus in central vestibular lesions is severe, dissociated, horizontal, rotatory or vertical, without changes related to optical suppression; if vestibular symptoms are present, they are non-harmonic. In central disorders, findings after thermal stimulation are either normal or pathological, with dysrhythmias and inhibition in pendular stimulation. This paper deals with differential diagnosis of vertigo based on anamnesis and clinical examination, as well as objective diagnostic tests.
 ...
PMID:Initial evaluation of vertigo. 1763 3

Peripheral and central vestibular syndromes are characterized by the combination of the four symptoms such as: vertigo, nystagmus, imbalance and nausea. Vertigo is the disturbance of the cortico-spatial orientation. Nystagmus is regarded as a secondary symptom caused by direction specific disequilibrium of the vestibulo-ocular reflex. Imbalance is caused by the abnormal activation of vestibulo-spinal pathways. Nausea is due to the activation of the medullary vomiting center. It is important that clinicians can establish an adequate diagnosis and differentiate vertigo and dizziness. The author--without the aim of completeness--discusses the types of vertigo caused by the most important disorders of the central nervous system, emphasizing the role of general practitioners in the diagnostic and therapeutic algorhytm.
 ...
PMID:[Vertigo in neurological diseases]. 1922 6

Nystagmus can be associated with strong discomfort due to oscillopsia, blurry vision and dizziness. Since generally no curative treatment methods exist, studies focus on potential pharmaceuticals to dampen the nystagmus. An overview is given on which forms of nystagmus can be treated with what kind of pharmacological substances and their possible mechanism of nystagmus dampening. Controlled studies found gabapentin and memantine to be effective in acquired pendular nystagmus and early-onset idiopathic nystagmus, and an efficacy of 4-aminopyridine in downbeat nystagmus.
 ...
PMID:[Pharmacological treatment of nystagmus]. 2125 46

Linear scleroderma is a kind of disease that can cause complication of the central nervous system. Sometimes, ipsilateral intracerebral or white matter lesions in the brain magnetic resonance imaging are noted. Nystagmus is important for the differential diagnosis of dizziness. Positional nystagmus was classified into regular direction nystagmus, direction changing positional nystagmus (DCPN) and irregular nystagmus by their character. DCPN is defined as a nystagmus that changes its direction with different head and body positions, and it can be the sign of lesion in the central vestibular system. Recently, we experienced a 17-year-old woman who had a scalp linear scleroderma, treated for about 10 years and showed DCPN induced by positional nystagmus test. We report a case of linear scleroderma accompanied by cerebellar lesion with a brief review of literature.
...
PMID:A case of linear scleroderma involving cerebellum with vertigo. 2465 78


1 2 Next >>