During the past 14 years from 1975 to 1989, two-nation-wide surveys of Meniere's disease have been carried out by the Vestibular Disorders Research Comittee of Japan, supported by the Ministry of Health and Welfare of Japan. However, an epidemiological case-control-study including normal subjects has not yet been performed by this committee.In this third survey, therefore, 148 patients with definite Meniere's disease, 138 with non-Meniere vertigo, 113 with rhinolaryngological disorders, and 165 normal control subjects were collected by the 16 mem-bers of the Research Committee from June 1990 to November 1990. The controls were selected to match as closely as possible the sex, age and location of the Meniere's disease patients.The characteristic epidemiological features of Meniere's disease in Japan were :1) Sex-ratio : 63 males to 85 female.2) Age-distribution : Peak at 40-49 years for males and 30-39 years for females.3) Season and Time of Onset : Often initial vertigo attacks occurred in the afternoon or in the morning.4) Occupational Distribution : There was a higher incidence of Meniere's disease among technicians or white-collar workers than among farmers, laborers engaged in blue-collar work, as in the 1st and 2nd surveys. However, the number of house-wives was lower in this 3rd survey.5) Personal characteristics : In patients with Meniere's disease, precisionism and neurosis were more frequently observed than in non-Meniere's vertigo.6) Preceding Events : Mental and physical fatigue before vertigo attacks was frequent in Meniere's disease patients.These epidemiological features reconfirm that the occurrence of vertigo attacks in Meniere's disease is influenced much more by individual factors than by environmental factors, as was found in the 1st and 2nd Nation-wide surveys. However, a marked difference in sex ratio with female preponderance was found in the 3rd survey.The incidence of bilateral Meniere's disease was 16.2% (24/148), higher than in the 1st and 2nd surveys.
Objective tinnitus is defined as tinnitus that is audible to others and is caused by myogenic or vascular diseases, etc. We report two cases of objective tinnitus caused by soft palatal myoclonus and dural arteriovenous fistula (DAVF). Case1: A 43-year-old man who presented with objective tinnitus caused by palatal myoclonus after subarachnoid hemorrhage. The objective tinnitus of clicking sounds could be heard through an otoscope His objective tinnitus could be heard synchronously with the soft palatial myoclonus. After conservative treatment with counseling, he tried consciously not to move his larynx, which led to improvement. The objective tinnitus caused by soft palatal myoclonus is considered to arise from the desorption sound between the soft palate and the posterior wall of the pharynx and desorption sound of the lumen of the eustachian tube. Case2: A 68-year-old man who complained of pulsating tinnitus; the tinnitus was synchronized with the cardiac pulsation, and auscultation of the temporal region revealed the pulsating tinnitus. MRI and MRA findings suggested an intracranial vascular lesion.
We have introduced a computer system to control and analyze equilibrium examinations in the clinical routine. An algorithm to analyze caloric responses, the usefulness of this system and parameters to evaluate the responses by computer analysis are reported. Caloric stimulation is given by 24°C cold and 50°C hot air at a 61/min. flow rate for one minute. Nystagmus waves elicited by the calorization are automatically identified, and the amplitude and velocity of nystagmus are calculated by on-line real time process. After all equilibrium examinations of a patient are completed, the caloric responses are computed and the results are printed on an X-Y plotter along with the results of optokinetic nystagmus and rotatory test. The slow phase velocity of each nystagmus are plotted and the values of duration, the number of nystagmus, maximum slow phase velocity and total amplitude in each calorization are indicated on the graph. The percentage of canal paresis (CP) and directional preponderance (DP) of each parameter are also printed on the graph. We can qualitatively observe caloric responses by the graph of the slow phase velocity and quantitatively evaluate disorders of the responses by the indicated values. Computer analysis of caloric nystagmus is very useful to evaluate responses correctly, particularly in cases showing such complicated responses as both CP and DP are combined or those are influenced by spontaneous nystagmus. We concluded that the maximum slow phase velocity is the best parameter to evaluate caloric test in the computer analysis.
We performed the Schellong test and measured the RR intervals on the ECGs of patients with equilibrium disorders to determine whether or not the autonomic nervous system was effected. The RR intervals were analyzed by a microcomputer to obtain two parameters, “CV%” (the static function of the autonomic nervous system while standing) and “A-B” (the dynamic function of the autonomic nervou system when changing from the supine to the standing position). The blood pressure was measured with an automatic sphygmomanometer. Both parameters (CV% and A-B) were outside the normal range more definitly in patients with central nervous system disorders than in those with peripheral vestibular disorders. This tendency was more marked for A-B.Furthermore, as the age of the patients increased, the incidence of abnormal A-B also increased in patients with peripheral vestibular disorders and in those with CNS disorders, especially the latter. The results of the Schellong test corresponded fairly well with the A-B findings. Therefore, it appears that disorders of the dynamic function of the autonomic nervous system cause an impairment of autoregulation originating in CNS disorders in elderly patients.
