Background: No studies of the prevalence of one of the most common movement disorders, essential tremor (ET), have been undertaken in the Faroe Islands. Given the potential for founder effects in the Islands, and the highly genetic nature of ET, the Faroe Islands provide a particularly interesting setting in which to study the prevalence of ET. Objective: To estimate the prevalence of ET and study its characteristics. Methods: We used a 2-phase, population-based design, screening 1,328 randomly selected Faroese individuals aged ≥40 years. A subsample of 282 individuals who had returned the spirals and questionnaire was selected to participate in an in-person clinical evaluation. Tremor was systematically quantified by a senior movement disorder neurologist with particular specialization in tremor using a reliable and valid clinical rating scale followed by the application of rigorous diagnostic criteria used by tremor investigators internationally. Results: The overall crude prevalence was 2.9%. The age-adjusted prevalence was 3.1%. There was an age-associated rise in prevalence; by age ≥70, prevalence reached 4.8%. Twenty six of 27 (96.2%) were previously undiagnosed. Conclusions: This is the first population-based study of the prevalence of ET in the Faroe Islands. The estimated prevalence was similar to studies using the same or comparable methodologies.

Background: There are fewer than five population-based studies of dystonia worldwide. Only one utilized a movement disorders neurologist. Given the potential for founder effects, and the highly genetic nature of dystonia, the Faroe Islands provide a particularly interesting setting to study the prevalence of dystonia. Objective: To estimate the prevalence of dystonia. Methods: We used a two-phase, population-based design, screening 1,334 randomly-selected Faroese individuals aged ≥40 years from which a subsample of 227 participated in an in-person clinical evaluation. Dystonia was assessed by two movement disorder neurologists using videotaped examinations. Results: Two of 227 (0.88%, 95% confidence interval [CI] −0.33%-2.09%) were diagnosed with cervical or segmental dystonia. An unusual form of thumb flexion dystonia was noted in 75 more, yielding a combined prevalence of 33.92% (95% CI 27.73%-40.11%). Conclusions: The prevalence of cervical or segmental dystonia was as high as in one prior population population-based study using similar methods. Furthermore, an unusual form of thumb flexion dystonia was uncovered, which yielded an extraordinarily high prevalence of dystonia in this population. Although our methods likely contributed to more complete capture of subtle

Background: Essential tremor (ET) is among the most prevalent neurological diseases. Its environmental determinants are poorly understood. Harmane (1-methyl-9H-pyrido[3, 4-b]indole), a dietary tremor-producing neurotoxin, has been linked to ET in a few studies in New York and Madrid. Mercury, also a tremor-producing neurotoxin, has not been studied in ET. The Faroe Islands have been the focus of epidemiological investigations of numerous neurological disorders. Objective: In this population-based, case-control study, we directly measured blood harmane concentrations (HA) and blood mercury concentrations (Hg) in ET cases and controls. Methods: In total, 1,328 Faroese adults were screened; 26 ET cases were identified whose (HA) and (Hg) were compared to 197 controls. Results: Although there were no statistically significant differences between diagnostic groups, median (HA) was 2.7× higher in definite ET (4.13 g -10 /mL) and 1.5× higher in probable ET (2.28 g -10 /mL) than controls (1.53 g -10 /mL). Small sample size was a limitation. For definite ET versus controls, p = 0.126. (Hg) were similar between groups. Conclusions: We demonstrated marginally elevated (HA) in definite and probable ET. These data are similar to those previously published and possibly extend etiological links between this neurotoxin and ET to a third locale. The study did not support a link between mercury and ET.

There are virtually no population-based data on tremor in normal individuals. Using a populationbased sample of 1,158 normal adults ages 40-98 years in the Faroe Islands, we characterized the extent of normal action tremor across age and gender strata. Participants drew two Archimedes spirals with each hand, and tremor was systematically quantified by a senior movement disorder neurologist using a reliable and valid ordinal rating scale (ratings = 0-3). Tremor was nearly universal-1,145 (98.9%) participants had a total mean spiral score >0. Older age was associated with more tremor (p<0.001) and spiral scores were higher in males than females (p<0.001). The proportion of individuals with a spiral rating ≥1.5 (i.e., more than mild tremor) was low (1.8%-8.5%); however, this value reached 19.6% in left-hand spirals of males >70 years old. In this

A 69-year-old man presented with acute vertigo, nausea, and vomiting. The patient had leftbeating nystagmus and an abnormal vestibulo-ocular reflex with corrective saccades on right head impulse (video 1). He had impaired pursuits to the left but no other cerebellar/neurologic findings (skew/hearing loss). MRI showed an acute stroke affecting the left cerebellar flocculonodular region (figure). Prior research has shown that an abnormal head impulse test (HIT) strongly predicts a peripheral process, and is inversely associated with posterior fossa stroke. 1 Our case illustrates the limited specificity of this clinical test. Nine percent of patients with a positive HIT have cerebellar strokes. 2 Author contributions Jens Witsch: clinical care of the patient, study concept, acquisition of data, revision of the manuscript for intellectual content. Monica Ferrer: acquisition of data, drafting of the manuscript. Dhasakumar Navaratnam: clinical care of the patient, study concept, acquisition of data, revision of the manuscript for intellectual content. Figure Brain MRI (A) Left cerebellar lesion, hyperintense on the diffusion-weighted imaging sequence (arrows in A and C). (B) Hypointense apparent diffusion coefficient sequence correlate of lesion shown in A. (C, D) Caudal extension of the lesion shown in A and B (thickness of cuts 5 mm).