Meniere's disease in Finland : an epidemiological and clinical study on occurrence, clinical picture and policy
1University of Oulu, Faculty of Medicine, Department of Otorhinolaryngology
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|Persistent link:|| http://urn.fi/urn:isbn:9514271130
|Publish Date:|| 2003-10-17
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic Dissertation to be presented with the assent of the Faculty of Medicine, University of Oulu, for public discussion in the Auditorium 7 of the University Hospital of Oulu, on October 17th, 2003, at 12 noon.
Professor Iain W. S. Mair
Docent Hannu Valtonen
The symptom complex originating from the inner ear, known as Meniere's disease, was studied especially from the epidemiologic point of view. A total of 442 patients' charts were retrospectively analysed in several hospital districts of Finland. The period of 1992-1996 was covered. The main focus was on the epidemiological assessment of the disease in Finland. To clarify the epidemiological figures, the validity of the diagnostic assessment was examined using the latest guidelines (1995) of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS) as a gold standard.
The diagnostic tools used in the different hospitals were documented and evaluated, and diagnostic accuracy at the different levels of the health care system was evaluated. The clinical picture of Meniere's disease was characterised, and the therapeutic modalities used were evaluated. The audiometric configurations were classified according to two principles. The prognosis of hearing impairment was specified by creating a multivariable model.
Half of the patients (N = 221) fulfilled the AAO-HNS criteria for definite disease. The prevalence and incidence of definite cases of Meniere's disease appeared to be lower in Finland than could be expected based on previous international studies. A prevalence of at least 43 per 100,000 and an average annual incidence of 4.3 per 100,000 were obtained. The prevalence rates in the catchment areas of the university and central hospitals did not differ statistically, but a significant (p < 0.001) difference was found between the average prevalences in the northern and southern Finnish hospital districts.
Fluctuation of hearing in repeated audiometric measurements appeared to be a highly sensitive (94%) diagnostic test to detect definite Meniere's disease. According to the multivariable model created in this study, the hearing impairment in Meniere's disease affects equally males and females, and the deterioration is about 1 dB per year due to the duration of the disease and 0.5 dB per year due to aging. The disease was controlled conservatively in 69% of the cases. A gently sloping high-frequency audiometric pattern was most prevalent according to the EU Work Group classification and a flat pattern according to the mid-frequency-based classification.
The variability of diagnostic criteria, diagnostic tools and therapeutic modalities shows an evident need for up-to-date therapy recommendations for Meniere's disease in Finland.
Acta Universitatis Ouluensis. D, Medica
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