Kanemasa Mizukoshi

Epidemiological Studies on Benign Paroxysmal Positional Vertigo in Japan

In 1980, the Research Committee of Peripheral Vestibular Disorders in Japan, which is supported by the Ministry of Health and Welfare, was founded by 24 members, from several districts in Japan. The Committees first task was to draft the diagnostic criteria for several peripheral vestibular disorders, such as benign paroxysmal positional vertigo (BPPV), and vestibular neuronitis. For the national epidemiological survey, they then collected the data on 101 cases of BPPV out of some 783 vestibular disorder patients. In addition, data on 103 patients of BPPV out of 559 vestibular disorder patients were also collected from the Neuro-otological Clinic of the Toyama Medical and Pharmaceutical University Hospital. From these epidemiological surveys, the incidence of BPPV in Japan was estimated at 10.7 per 100,000 population, while that of BPPV in Toyama was estimated at 17.3 per 100,000 population. The ratio of BPPV was higher in female than male patients in both surveys. The age at the onset of BPPV peaked in the fourth decade in both males and females. Compared with the other epidemiological features of Menieres disease and sudden deafness with vertigo in the same surveys, it appeared that the characteristic features of BPPV are epidemiologically similar to those of Menieres disease, but different from those of sudden deafness.

Epidemiological and Clinical Characteristics of Meniere's Disease in Japan

From 1975 to 1990, nationwide surveys on Menières disease were performed three times by the Research Committee of Menières disease (1975-76) and the Research Committee of Peripheral Vestibular Disorders (1982-84 and 1990) in Japan. Nine hundred and fifty-eight definite Menière cases, 520 in the 1st, 230 in the 2nd and 148 in the 3rd survey, were sampled by the members of the Committees. The epidemiological and clinical characteristics of Menières disease were analyzed and compared with such control cases as other vertiginous patients, ENT patients without vertigo, and healthy subjects. In Menières disease, the male to female ratio has changed from even to female predominance over the 15 years the study ran. The age distribution at onset peaked in the forties for males and thirties for females. Significant epidemiological results are summarized as follows: Definite Menières disease has a higher incidence in married persons and in people with a nervous and precise character, whereas the incidence is lower in obese people. Physical and mental fatigue induced the onset of attacks. Menières disease happened in day time in many cases, especially during the afternoon. As these epidemiological findings were commonly observed in all the surveys, the results are considered to be universal epidemiological characteristics of Menières disease in Japan. In the same period, regional investigations were performed by Toyama Medical Association and our University. The male to female ratio in Toyama indicated a more significant female predominance than in the nationwide surveys. The prevalence of Menières disease in Toyama Prefecture has been almost constant in all surveys, about 17/100,000 since 1974.(ABSTRACT TRUNCATED AT 250 WORDS)

The contribution of proprioception to posture control in normal subjects.

In order to investigate the contribution of proprioceptive input to maintaining an upright position, stabilometry via 100-Hz vibratory stimulation applied to the Achilles tendon was studied and analyzed with respect to area, length and power spectra according to the method of fast Fourier transform (FFT). Twenty-one young medical students were analyzed in this study. When vibration was applied, the body sway was significantly greater than that of control in area and length with both eyes open and closed. There was a significant increase of total power in both the lateral (X) and antero-posterior (Y) directions with the eyes closed. With the eyes open, an increase was found only in the antero-posterior direction. The frequency band indicating the maximum spectrum did not shift. Significant increases in power spectra were found in the frequency range of more than 2 Hz in both two directions with the eyes closed. It was concluded that a vibration given to the Achilles tendon provoked a pronounced high frequency body sway especially in the antero-posterior direction when visual information was nullified, and that proprioceptive information may have a minor role compared with visual information.

A CLINICAL STUDY OF ELECTROCOCHLEOGRAPHY IN MENIERE'S DISEASE

Electrocochleography (ECochG) of 168 ears with definite Menieres disease was studied. The results were compared with recordings from 29 normal ears and 444 ears with other types of sensorineural hearing loss. It is shown that the SP/AP ratio is much more useful than SP amplitude for detecting endolymphatic hydrops. There was little difference in the mean values of SP/AP from those proposed by many other investigators; the mean values all being near 0.25. From 0.30 to 0.40 of SP/AP was considered adequate as the upper limit. Following intravenous administration of glycerol, a significant decrease in SP/AP was found in 21 Menieres ears. However, there was no change of SP/AP after oral administration of glycerol and isosorbide. This difference may be due to the fact that a larger oral than intravenous administration is necessary to affect SP/AP. Although a postoperative decrease of 10% or more in SP/AP was observed in 5 patients, 10 patients followed up for 2 years or more after surgery did not show a statistically significant change of SP/AP and pure tone threshold. ECochG should be repeatedly recorded to be useful as a monitor for the presence of hydrops. It is discussed whether biochemical or mechanical changes in endolymph may cause a decrease in SP/AP after the use of dehydrating agents and endolymphatic sac surgery.

Epidemiologic characteristics of definite Ménière's disease in Japan : A long-term survey of toyama and niigata prefectures

To identify epidemiologic characteristics of definite cases of Ménière’s disease (DMD), we conducted retrospective surveys of the period 1990–2004 of the Nishikubiki district and of the period 1980–2004 of Toyama Medical and Pharmaceutical University. Three hundred and seventy-five patients (50 from Nishikubiki, 325 from Toyama) were diagnosed with DMD according to the diagnostic criteria proposed by the Japanese Society for Equilibrium Research. There was a slight increase in the prevalence of DMD during the period 1990–2004. However, incidence did not change significantly over time. The average annual prevalence and incidence were 34.5 and 5.0, respectively, per 100,000 population. Incidence and prevalence predominated in females. With respect to age at disease, the incidence in elderly patients was increased when we corrected for age distribution in the overall population.

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.

Clinical Features of Cisplatin Vestibulotoxicity and Hearing Loss

Patients treated with cisplatin were observed in an otoneurological study with special reference to cochlear and vestibular toxicity. Toxicity-related symptoms appeared to be almost all transient. As with leukopenia, hearing loss and dizziness often occurred after several weeks of administration. In the equilibrium examinations, some abnormal findings such as spontaneous nystagmus and positional nystagmus were seen. Caloric tests and body sway tests detected abnormal findings in the early stages of cisplatin-related vestibulotoxicity.

Facial nerve palsy as a complication of parotid gland surgery and its prevention

The incidence of postoperative facial palsy in 73 patients who had under-gone surgery for parotid gland tumor is reported. Slight facial palsy occurred in 9 (14%) of 66 benign tumors but recovered completely within 3 months following surgery. However, in 7 patients with malignant tumors, 3 (43%) developed permanent palsy and 1 (14%) temporary palsy. The incidence of benign tumors depends on the tumor size and localization. However, the incidence decreased considerably in the last 6 years compared to the first 6 years. This is considered to be due to routine use of computed tomography with sialography and microsurgery during parotidectomy.

Nasal septal neurinoma.

A case of nasal septal neurinoma is presented. The patient was a 71-year-old male who complained of nasal obstruction and epistaxis. Results of the physical examination showed a giant mass filling the nasal cavity and the nasopharynx. A biopsy taken from its tissue surface showed histological features of neurofibroma. The lesion was completely resected with the patient under general anesthesia. The tumor completely occupied the right nasal cavity and the nasopharynx, partially penetrated the nasal septum and extended to the left nasal cavity. After the operation, the final pathological diagnosis was not neurofibroma but neurinoma in which Antoni type A and type B cells were mixed. The postoperative course was uneventful, and no recurrence has been observed to date.

Epidemiological Survey of Definite Cases of Meniere’s Disease Collected by the Seventeen Members of the Meniere’s Disease Research Committee of Japan in 1975–19761

Between Aril 1975 and December 1976, the second nationwide survey of Menieres disease in Japan was made by the 17 members of the Menieres Disease Research Committee of Japan. The epidemiological data from 520 patients with definite Menieres disease were analyzed in comparison with those from the 126 patients in the non-Meniere vertiginous group (Control A) and the 228 patients in the rhinolaryngological group (Control B). The male:female ratio of definite cases of Menieres disease was almost the same, and the age distribution peaked at the age group of 40--49 years for males, while the peak for females was at the age group of 30--39 years. 5.8% of the 520 patients had a close relative who also suffered from Menieres disease. From the epidemiological features, it may appear that the occurrence of vertiginous attacks in Menieres disease is influenced much more by individual than by environmental factors. However, this feature can be considered as another evidence of the psychosomatic disorders involved in Menieres disease.