1/5. Abnormal vestibular evoked myogenic potentials in the presence of normal caloric responses.OBJECTIVE: Combined use of vestibular evoked myogenic potential (VEMP) and caloric response testing has enabled us to examine the function of the inferior and superior vestibular nerves separately. Although results of VEMP testing and caloric response testing have been reported for many diseases, a clinical entity showing abnormal VEMP responses but normal caloric test responses has rarely been reported. The aim of the study was to investigate clinical features of diseases showing abnormal VEMP responses with normal caloric test responses. STUDY DESIGN: Retrospective. SETTING: University hospital. patients: Eight hundred eleven patients with balance problems who had undergone both caloric response and VEMP testing were included in the study. MAIN OUTCOME MEASURES: The amplitudes and latencies of the first positive-negative peak of the VEMP (p13-n23) were measured. RESULTS: Forty of the 811 patients (5%) were found to have abnormal VEMP responses with normal caloric test responses. Clinical diagnoses of these patients were Meniere's disease (n = 12), acoustic neuroma (n = 8), sudden deafness with vertigo (n = 6), and other diseases (n = 6). Eight patients could not be diagnosed as having a disease already recognized. Clinical manifestations of these eight patients were rotatory vertigo in six patients and non-rotatory dizziness in two. None of these patients showed abnormalities other than VEMP responses on neurologic or neurotologic examinations. CONCLUSION: Apart from Meniere's disease, acoustic neuroma, and sudden deafness with vertigo, which are already known as diseases with abnormal VEMP responses but normal caloric test responses, some patients might be diagnosed as having a disease that involves only the inferior vestibular nerve region.- - - - - - - - - - ranking = 1keywords = caloric (Clic here for more details about this article) |
2/5. Diffential diagnosis of the caloric nystagmus.Diagnostic considerations based upon the nystagmogram are limited. Quantitative assessment of horizontal canal sensitivity is available through the use of culmination frequency or culmination slow phase velocity. Qualitative characteristics of nystagmometry have been sought but with no satisfactory results. Three distinctive features of the caloric nystagmus were evaluated and were found to be suggestive or outrightly pathognomonic for retrolabyrinthine or central nervous system abnormalities. These are: (1) Vestibular decruitment. The disproportionate caloric responsiveness when a weak stimulus elicits a more intense nystagmic reaction than a strong stimulus is capable of creating. (2) Hyperactive vestibular responsiveness (3) Ocular fixation reversal phenomenon. Contrary to the normal behaviour, the elimination of fixation decreases the nystagmus intensity instead of facilitating the evoked nystagmus. The assessment of these qualitative features of the caloric nystagmus in addition to the quantitative measurements widens the scope of our diagnostic capabilities.- - - - - - - - - - ranking = 0.63636363636364keywords = caloric (Clic here for more details about this article) |
3/5. electronystagmography in neurological diagnosis.electronystagmography (ENG) is a technique for recording nystagmus and other eye movements; our technique, based on the utilization of a bioelectrical potential which exists between the retina and the cornea, has been reported in detail elsewhere in a monograph [29]. ENG has been used particularly by otologists to record caloric nystagmus and study labyrinthine function [2, 4, 16, 19]. This technique should have even greater applications in the diagnosis of neurological disease, since nystagmus and abnormalities of ocular and vestibular functions are symptoms frequently encountered by the neurologist. This paper illustrates this point with three case reports.- - - - - - - - - - ranking = 0.090909090909091keywords = caloric (Clic here for more details about this article) |
4/5. 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 = 0.090909090909091keywords = caloric (Clic here for more details about this article) |
5/5. multiple sclerosis presented acute hearing loss and vertigo.A case of multiple sclerosis with acute deafness and dizziness as initial symptoms was reported. The pure-tone audiometry showed a high-frequency sensorineural hearing loss; in the auditory evoked brain stem response (ABR), the left side had a normal peak I with an absence of subsequent peaks. In the equilibrium test, Bruns' nystagmus was present, and the caloric test demonstrated CP on the left side. MRI disclosed a high-intensity lesion in the cerebellar peduncle (T2-weighted image). With steroid therapy, the deafness and dizziness improved within 10 days, although, after 20 days, the findings of the ABR and caloric test remained unchanged.- - - - - - - - - - ranking = 0.18181818181818keywords = caloric (Clic here for more details about this article) |