1/13. Clinical features of sudden hearing loss associated with a high signal in the labyrinth on unenhanced T1-weighted magnetic resonance imaging.We report on five patients with high signals in the labyrinth on unenhanced magnetic resonance imaging who developed sudden hearing loss and vertigo. Weissman et al. (1992) suggested the possibility that such high signals were caused by hemorrhage. We assessed these patients using audiograms, caloric tests, and auditory brainstem responses to investigate the possibility of inner ear hemorrhage. Most of the patients were found to have severe and irreversible impairment of both cochlear and vestibular function. These findings were consistent with the hypothesis that their symptoms were caused by inner ear hemorrhage.- - - - - - - - - - ranking = 1keywords = caloric test, caloric (Clic here for more details about this article) |
2/13. Caloric-eye tracking pattern test: I. Visual suppression and the possibility of simplified differential diagnosis between peripheral and central vertigo.During the examination of patients who complain of vertigo or who have equilibrium disorders, it is often difficult to determine the etiology of the disorders, that is, to determine whether it is dependent on a peripheral or central vestibular disorder. To attempt to guess the etiology in these cases, we devised a new method: the caloric eye-tracking pattern test. In normal subjects and in patients with peripheral disorders, as is well known, caloric nystagmus has little influence on the eye-tracking pattern. In contrast, in patients with central vestibular disorders, caloric nystagmus evoked abnormalities on the eye-tracking pattern, either superimposed or saccades, in spite of the fact that the eye-tracking pattern before the caloric stimulation is normal. These findings result from the visual suppression mechanism to the vestibular nystagmus. We can say that the visual suppression to the vestibular nystagmus is evoked more strongly bu pursuing a moving visual stimulus than by gazing at a stationary target. These results are interesting, not only form the physiological view point, but also from the clinical view point. There is a possibility of the differential diagnosis between peripheral and central vertigo.- - - - - - - - - - ranking = 0.25089793186898keywords = caloric (Clic here for more details about this article) |
3/13. Labyrinthine anomalies with normal cochlear function.Three cases of labyrinthine anomaly confirmed by polytomography and CT scan are reported. They showed similar dysplasia of the bony labyrinth: dilation and fusion of the lateral semicircular canal (SCC) and of the vestibule with a normally shaped cochlea and other SCCs. One side was involved in 2 cases and both sides in 1 case. The 1st case showed normal hearing levels with markedly reduced response to caloric stimulation in the affected ear. The 2nd case showed conductive hearing loss due to cholesteatoma with normal bone conduction hearing levels and normal caloric response. The 3rd case showed bilateral conductive hearing loss of unknown cause. The classification of labyrinthine anomalies and labyrinthine functions is discussed. Labyrinthine anomaly detected by CT scan and polytomography can be present in patients with normal cochlear and/or vestibular function.- - - - - - - - - - ranking = 0.12544896593449keywords = caloric (Clic here for more details about this article) |
4/13. Retro-labyrinthine disorders detected by galvanic body sway responses in routine equilibrium examinations.Galvanic stimulation applied to the head provides important information for differential diagnosis between inner ear and retro-labyrinthine disorders of the vestibular system. So far, galvanic stimulation has been difficult to introduce in routine practice because of side effects such as severe pain around the electrode area. We have developed a new method to record fine body sway elicited by low current stimulation of less than 0.4 mA and to quantitatively evaluate the responses by Fourier transform. During the past 5 years, 502 patients, showing uni- or bilateral canal paresis in the caloric test or findings of central disequilibrium, were tested by this method without producing any side effects. In 122 patients (24.8%), such as sudden deafness, acoustic tumour, vascular disorders of the CNS system and so on, findings of retro-labyrinthine disorders were detected. It has been concluded that this method was easy to perform and very useful for differential diagnosis of diseases of the vestibular system.- - - - - - - - - - ranking = 1keywords = caloric test, caloric (Clic here for more details about this article) |
5/13. Acute vestibular paralysis in herpes zoster oticus.A case of herpes zoster oticus is presented in which the lateral and superior semicircular canals of the labyrinth were affected unilaterally. The results of several electronystagmographic examinations are described and correlated with the patient's description of symptoms. This case study indicates that disease affecting the lateral semicircular canal is reliably detected by the conventional caloric test. However, the fact that the posterior semicircular canal remained intact could not be inferred from the results of the caloric test in this case. Also the appearance of nystagmus upon eye closure appears to have been a more sensitive index of the state of the disease process than was the caloric test.- - - - - - - - - - ranking = 3keywords = caloric test, caloric (Clic here for more details about this article) |
6/13. Floccular inhibition of the vestibulo-ocular reflex in man.The vestibulo-ocular reflex (VOR) plays a major role in ocular motility. Stimulation of each semicircular canal produces excitation of a specific extraocular muscle and inhibition of its antagonist in each eye. Floccular inhibition of the VOR has been extensively studied in the rabbit. Inhibitory projections from floccular purkinje cells reach the ipsilateral vestibular nucleus via the restiform body and selectively control certain VORs. We examined the ocular functions in a patient with a lateral lower pontine infarct that included the restiform body. The patient exhibited unilateral, selective disinhibition of the VOR manifested by disconjugate upward rotatory drift of the eyes at the end of lateral eye movement towards the side of the lesion. He had marked directional preponderance on caloric testing. The same underlying mechanism which produced the biased VOR also appeared to affect target position determination in fast eye movements, resulting in lateropulsion of saccades and asymmetric OKNs. This is the first clinical case supporting the theory of selective cerebellar inhibition of the VOR.- - - - - - - - - - ranking = 1keywords = caloric test, caloric (Clic here for more details about this article) |
7/13. An algorithm for neurotologic disorders.In the evaluation of patients with complaints of dizziness, hearing loss, and/or tinnitus, the primary objective is to determine the site of the lesion. An accurate localization of the lesion is important for selecting the most appropriate radiologic study. The information obtained from the vestibular and audiometeric evaluations identifies the site of the lesion accurately. For the vestibular evaluation we use photoelectric nystagmography (PENG) and the Torok monothermal differential caloric test. The initial audiometeric evaluation consists of a pure-tone audiogram and speech discrimination scores. Additional audiometric site-of-lesion tests and ABR are used selectively as the diagnostic yield of these tests does not significantly add to the information already obtained from the vestibular evaluation. If the lesion is suspected to lie in the middle ear or internal auditory canals, we use pluridirectional tomography. For further delineation of lesions confined to the internal auditory canal we use pneumo-CT. For suspected morphologic lesions of the posterior fossa we use thin-section CT with enhancement. review has proved useful in defining petrous apex and skull base lesions. CT-rBBC studies have proved valuable in objectively demonstrating a deficient perfusion of the brain. The vascularity of certain lesions such as glomus tumors can be satisfactorily confirmed by this technique.- - - - - - - - - - ranking = 1keywords = caloric test, caloric (Clic here for more details about this article) |
8/13. dizziness in childhood.dizziness in childhood is not an infrequent symptom. Accurate history taking and close co-operation between otologist, paediatrician and neurologist are necessary in the approach to the dizzy child. Most cases of childhood dizziness settle in time and investigations should be carefully selected; those with severe and persistent dizziness or ataxia should be thoroughly investigated including: EEG, ENG, calorics and CT scan. The conditions causing dizziness in children are discussed and are illustrated with case histories from our series of 27 children. dizziness of unknown aetiology, serous otitis media and benign paroxysmal vertigo were the most common diagnostic labels applied to our patients. Treatment is rarely necessary but dimenhydrinate or a labyrinthine sedative in those with troublesome vertigo, or the adjustment of the medical regime in those epileptics on phenytoin, may be beneficial. Surgical intervention is only required in those with an operable lesion.- - - - - - - - - - ranking = 0.062724482967245keywords = caloric (Clic here for more details about this article) |
9/13. Inner ear histopathology in patients treated with cis-platinum.temporal bone histopathology was studied in five patients (aged 51-67) who received cis-diamminedichloroplatinum (DDP) chemotherapy for head and neck squamous cell carcinoma. In each case, sensorineural hearing loss occurred during the course of treatment and temporal bones were acquired 3-5 hours postmortem for anatomical study. Scanning electron microscopy revealed acute degenerative changes in cochlear hair cells that appeared to be the result of drug treatment. However, the presence of age-related degeneration made it difficult to unequivocally identify hair cell loss due solely to ototoxicity. In one patient, a decrement in vestibular function was observed during DDP treatment. Postmortem examination showed severe degeneration of the maculae and cristae which could be correlated with the absence of caloric response seen after chemotherapy.- - - - - - - - - - ranking = 0.062724482967245keywords = caloric (Clic here for more details about this article) |
10/13. Diagnostic advantages of the Torok monothermal differential caloric test.In the Torok monothermal differential caloric test, each ear is irrigated with 10 ml and 100 ml of water at 20 degrees C in 5 and 20 sec., respectively. The intensity of the induced nystagmus is expressed in terms of frequency at culmination. The ratio between the weak and strong caloric responses may be normal of disproportionately large or small. When large, the ratio exceeds 3.5 and is called vestibular decruitment, a sign of labyrinthine disease. A ratio of 1.1 or less is called vestibular decruitment, a sign indicative of posterior fossa abnormality. Of 54 patients showing decruitment, a central lesion was confirmed in 51, an identification rate of 94%. The test is thus valuable in differentiating labyrinthine from retrolabyrinthine lesions.- - - - - - - - - - ranking = 5.0627244829672keywords = caloric test, caloric (Clic here for more details about this article) |
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