THE EPIDEMIOLOGY OF PARKINSONS-DISEASE IN THE COUNTY OF ROGALAND, NORWAY

The objective of this investigation was to clarify the epidemiology of idiopathic Parkinson's disease (PD) in the county of Rogaland, Norway . Total case ascertainment and a high diagnostic accuracy were attempt ed through a detailed community study and the use of a new clinical di agnostic classification. The study population comprised 220,858 inhabi tants, and a total of nearly 400 patients was interviewed and examined by a neurologist. On prevalence day, January 1, 1993, 245 patients we re included in the study, The diagnostic classification revealed 135 p atients with clinically definite, 74 with probable, and 36 with possib le PD. The crude prevalence rate was shown to be 110.9 per 100,000 inh abitants. The total age-adjusted prevalence was calculated to be 102.4 per 100,000 and to 120.9 per 100,000 men and 89.8 per 100,000 women. Among the 245 patients, 28 patients had a tremor-dominant disease, 50 patients an akinetic-dominant disease, and 167 patients a mixed clinic al pattern of PD. Age-adjusted prevalence figures were slightly higher for rural compared to urban areas. About 50% of the PD patients were in need of public help, 15% had complaints about pain related to their parkinsonism, and after similar to 6 years of levodopa treatment, 20% were suffering from clinical fluctuations. The study showed that 40% of the patients had some degree of thought disorder. The prevalence fi gures for PD in this study are slightly lower than those reported from most previous prevalence studies with a comparable study design for c ase finding. This may be due to a careful diagnostic evaluation with t he use of specified diagnostic criteria, excluding patients with other parkinsonian syndromes.