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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.

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Background Remote assessment of essential tremor (ET) is unverified. Objectives To compare assigned tremor scores from a remote videotaped research protocol with those from an in‐person videotaped research protocol and assess the validity of remote and in‐person videotape‐based diagnoses when compared against the intake diagnosis (ET vs. control). Methods Participants with intake diagnoses of ET (11) or controls (15) completed a tremor examination that was filmed both remotely and in person. Results Agreement between the tremor ratings assigned during remote and in‐person videos was substantial (composite κw, 0.67; mean Gwet's AC2 score, 0.92; mean percent agreement, 63.7%). In ET cases with less severe tremor, agreement was lower (p = 0.008). Diagnostic validity was high for both remote and in‐person videos compared to the intake diagnosis. Conclusions Remote video is a reasonable alternative to in‐person video for the assessment of tremor severity and assignment of ET diagnoses. However, at low tremor amplitudes, agreement declines.