High prevalence of primary focal dystonia in the Faroe Islands

OBJECTIVE

There are no previous studies undertaken about primary focal dystonia in the Faroe Islands. The aim of this study was to establish the prevalence of these diseases in the Faroese population.

METHODS

Patients were ascertained and registered prospectively from January 1, 1994, through 2013 when they were examined at the Neurological Clinic of the Faroese National Hospital or at a private neurological practice, which together constitutes all the available neurological services in the Faroe Islands.

RESULT

On January 1, 2014, there were 29 individuals within the entire Faroese population of 48,100 with primary focal dystonia: 23 with torticollis, four with writer's cramp, one with oromandibular dystonia, and one with laryngeal dystonia; no one had blepharospasm. The prevalence of primary focal dystonia was 602 per million (395-873) (95% confidence limit). The most common subtype was cervical dystonia with a prevalence of 478 (332-728) per million.

CONCLUSION

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.

Myasthenia gravis incidence in a general North Atlantic isolated population

OBJECTIVE

There are no previous studies undertaken about myasthenia gravis in the Faroe Islands. The aim of this study was to establish the incidence of onset of this disease in the Faroese population.

METHOD

Patients were ascertained and registered prospectively from 1986 to 2013 when they were examined at the Neurological Clinic of the Faroese National Hospital or at a private neurological practice, which constitutes all the available neurological services in the Faroe Islands.

RESULT

Twelve new diagnoses were made over a 27-year period, providing an incidence density rate of 9.4 per million person-years (95% confidence limit 4.9-16.5). At presentation, nine of 12 patients had generalized myasthenia gravis and two patients had pure ocular disease, and in one patient, the symptoms were restricted to the bulbo-facial muscles. The sex ratio was 2:1, F/M. In nine of the cases, a positive result of acetylcholine receptor antibody assay was documented. In all patients, there was a beneficial response to anticholinesterase administration.

CONCLUSION

The result yielded no strong evidence of a difference in incidence between that found in the Faroe Islands and those in most European studies, apart from recent studies from London, UK; Norway; Spain, and Italy in which incidences from 21 to 30 per million person-years had been reported.

Incidence of amyotrophic lateral sclerosis in the Faroe Islands

OBJECTIVES

The establishment of variations in the incidence of amyotrophic lateral sclerosis (ALS) in the Faroese population from that found in other general populations may point to risk factors for the development of this disease among the Faroese. The aim of this study was to estimate the annual incidence of ALS during the period 1987-2009 and to compare the occurrence of ALS in the Faroe Islands with data from three European countries.

METHOD

All Faroese patients diagnosed with ALS in this period are documented in the current longitudinal prospective study.

RESULTS

The incidence of ALS in the Faroe Islands during the period 1987-2009 is 2.6 (1.7-3.7) per 100,000 annually. The results yielded no strong evidence of a difference (P = 0.09) in the incidence of ALS between Faroe Islands and Europe. The sample population is small, and this, of course, impacts the statistical precision of the findings.

CONCLUSION

The data clearly suggest, however, that the Faroese population is probably not subject to an increased risk of ALS, even though certain risk factors are present in the general population: (i) a fish-based diet contaminated with mercury and polychlorinated biphenyl; (ii) the high occurrence of the recessive carnitine transporter genetic defect; and (iii) the anticipated high degree of inbreeding at the fifth generation.

Prevalence and incidence of Parkinson's disease in The Faroe Islands

OBJECTIVE

A study in The Faroe Islands in 1995 suggested a high prevalence of idiopathic Parkinson's disease (IPD) and total parkinsonism of 187.6 and 233.4 per 100,000 inhabitants respectively.

METHODS

Detailed case-finding methods 10 years later were used and a neurologist has verified the diagnosis.

RESULTS

The crude prevalence of IPD and total parkinsonism was 206.7 per 100,000 and 227.4 per 100,000 respectively. The age-adjusted prevalence is twice as high as data from Norway and Denmark. Age at initiation of treatment and the fatality rate did not explain the increased prevalence. During 1995-2005, the average annual incidence was 21.1 per 100,000 persons for Parkinson's disease, and 22.9 per 100,000 persons, if including atypical parkinsonism.

CONCLUSION

The high prevalence was verified and linked to a high incidence. The cause of the high prevalence is unknown, but neurotoxic contaminants in traditional food may play a role in the pathogenesis in this population, perhaps jointly with genetic predisposition.

High prevalence of Parkinson's disease in the Faroe Islands

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.

Danish very-low-dose aspirin after carotid endarterectomy trial

The effect of very-low-dose aspirin as an antithrombotic agent was evaluated blindly in 301 patients who had recently undergone carotid endarterectomy. After randomization, 150 patients received aspirin and 151 received placebo. The two groups were comparable with regard to age, sex, blood pressure, previous cerebrovascular events, and smoking habits. The effect of the study medication on platelet aggregation was measured twice in each patient during the first 2 months and at each follow-up visit; the dose was individually adjusted. In 76% of the patients receiving aspirin, 50 mg/day gave satisfactory platelet inhibition, 13% needed 60 mg/day, 8% needed 70 mg/day, and 3% needed 100 mg/day. Platelet aggregation was found to be inhibited in only 1.2% of the measurements in the patients receiving placebo. Observation during treatment averaged 21 months; total intention-to-treat follow-up averaged 25 months. For the combined outcome events of transient ischemic attack, stroke, acute myocardial infarction, and vascular death, aspirin reduced risk by 11% (95% confidence limits: -38% to 48%, p greater than 0.1). Thus, there was no significant effect of very-low-dose aspirin in our trial.

Prevalence, incidence, and classification of epilepsy in the Faroes

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.

Subarachnoid hemorrhage in an isolated population. Incidence on the Faroes during the period 1962-1975

In a retrospective study of a 14-year period (1962-1975) the annual incidence of subarachnoid hemorrhage (SAH) was found to be 7.4 per 100,000 in an isolated population of about 40,000. The age-specific incidences in the age groups from 15-25 to 60 years are on the same level as found in Sweden, Rochester USA, England, and Iceland, but lower than the findings in Finland. The age-specific incidence among persons over 60 years of age was far lower than in Sweden, Rochester USA, and Finland. The possible causes of the lower incidence in all age groups than reported in the above-mentioned studies are discussed. Forty patients had a history of SAH. Two months after the episode 38% had died and at the end of 5 years 53%. The recurrence rate at 5 years was 24%.

Chronic paroxysmal hemicrania: continued remission of symptoms after discontinuation of indomethacin

Discontinuation of indomethacin in chronic paroxysmal hemicrania (CPH) usually causes relapse of symptoms within a few days. A patient with characteristic symptoms of CPH is reported. The patient had daily attacks of unilateral headache accompanied by ipsilateral lacrimation and conjunctival injection, a frequency of attacks between four and fourteen per day, and never a headache-free day. He was treated with indomethacin, and all symptoms disappeared within 24 h. After three months indomethacin was discontinued. Six months after that the patient was still symptom-free.

Clonazepam (Rivotril) and carbamazepine (Tegretol) in psychomotor epilepsy: a randomized multicenter trial

The antiepileptic properties of carbamazepine (Tegretol) and clonazepam (Rivotril) were compared in a double-blind randomized study comprising 36 patients with newly diagnosed, untreated psychomotor epilepsy (partial seizures with complex symptomatology). No significant differences were found between the two drugs during the 6 months of treatment. Measurements of concentrations in plasma confirmed that the patients exceeded the accepted lower limit for therapeutic range of the drugs.

Incidence of primary intracranial neoplasms in an isolated population (the Faroese) during the period 1962-1975

In a retrospective analysis covering a 14-year-period (1962-1975) the annual incidence of primary intracranial neoplasms in an isolated population of about 40,000 (the Faroese) was found to be 9.9 in 100,000. Out of the 52 patients with intracranial neoplasms 20 were alive, while 32 had died when the study was closed on 31st December 1979. Eighteen out of the 34 patients with supratentorial tumours and one patient with acoustic neurinoma had epilepsy.