We used several case-findings methods and strict criteria for case ascertainment to diagnose parkinsonism and idiopathic Parkinson's disease (PD) in the Faroe Islands. In the last few years before the prevalence date of July 1, 1995, we searched various registries from pharmacies, hospitals, and general practices, and found 195 patients with suspected parkinsonism out of 43,709 inhabitants. After excluding those who died before the prevalence date or were treated with levodopa (LD) for other diseases, a total of 124 patients remained for study, of whom 122 participated. We found 102 patients with parkinsonism and 82 with PD versus the expected 53 (p < 0.001, age-specific prevalences in the county of Rogaland, Norway). The overall prevalence of PD was estimated to be 187.6 and the age-adjusted prevalence to be 183.3 versus 110.9 per 100,000 inhabitants in the county of Rogaland. Compared to the study from Rogaland, the mean age at onset of PD symptoms, the mean age at the prevalence date, and the duration of PD indicated that the higher prevalence was not due to either an early onset nor to a longer duration of PD. A lower proportion of definite PD, a lower mean score on the Hoehn-Yahr scale, and a lower average dose of LD suggest that the high prevalence may be due to early diagnosis and a higher ascertainment of cases with mild disease. However, a high incidence cannot be excluded.

In a retrospective study covering 11 years (1970-80) the annual incidence of epilepsy in the isolated population of the Faroes (approx. 43,000 inhabitants) was found to be 42 per 100,000. The prevalence of all types of epileptic seizures has been found to be 763 per 100,000 on prevalence day, December 31, 1980. The relative frequency of different types of epilepsy in accordance with the International Classification of Epilepsies (1969) is reported.

The study yielded that (i) the prevalence of primary focal dystonia of 602 (395-873) per million is far higher in the Faroe Islands than that revealed in most other regions studied and (ii) the prevalence of the cervical dystonia subtype is far more common than elsewhere with the highest prevalence of 478 (332-728), which is higher than described in any previously published survey. As the study is serviced-based, the result may underestimate actual occurrence; thus, prevalence rates may be even higher.