The decision to treat patients with essential tremor (ET) is based primarily on the functional impact of the tremor. Correlates of functional disability, apart from the severity of the tremor itself, have not been studied. The objective of this work was to study correlates of functional disability in ET, and to present data on the extent of functional disability in community-dwelling ET cases. ET cases and age-matched control subjects were ascertained from a tertiary referral center at Columbia-Presbyterian Medical Center and a community in northern Manhattan, N.Y. Subjects underwent a 2.5-hour evaluation, including a tremor disability questionnaire, a videotaped tremor examination rated by a neurologist, a performance-based test of function, quantitative computerized tremor analysis, the Hamilton Anxiety Rating Scale, and the depression module of the Structured Clinical Interview for DSM-IV. Seventy-six (85.4%) of 89 cases reported disability on > or =1 item on the disability questionnaire. In multivariate linear regression analyses, current major depression, Hamilton Anxiety Rating Scale score, age, and tremor severity were independently correlated with performance-based test scores. Twenty-seven (73.0%) of 37 community cases reported disability on > or =1 (mean = 8.4) item on the questionnaire, and 25 (67.6%) demonstrated moderate or greater difficulty on > or =1 (mean = 4.2) task in a performance-based test. Depression, anxiety, and age, independent of the severity of tremor, were associated with greater functional disability in ET, so that these factors must be considered when assessing the impact of new treatments in ET. Among a group of community-dwelling cases, approximately three-quarters reported disability, suggesting that the number of individuals who might receive some benefit from advances in the treatment of ET is probably a great deal larger than previously thought.

Essential tremor (ET) is a common condition that is present in as many as 23% of elderly individuals. Our objective was to determine the risk of ET and to study the impairment resulting from ET among relatives of ET cases compared to relatives of controls. ET cases and matched controls from the Washington Heights-Inwood community, New York, and their first- and second-degree relatives underwent a standardized tremor examination. The risk of having ET in relatives of cases vs relatives of controls was compared using Cox proportional hazards models. Five hundred ninety-one subjects were examined (59 ET cases, 72 controls, 234 case relatives, and 226 control relatives). ET was present in 25 (22.5%) of the 111 first-degree relatives of cases compared to 6 (5.6%) of 107 first-degree relatives of controls [relative risk (RR) = 4.67, 95% confidence interval (CI) = 1.90-11.49, p = 0.0008]. RRs were higher in relatives of cases with onset < or =50 years than in those with later onset (RR = 10.38 vs 4.82). Sixteen (64%) of twenty-five affected first-degree case relatives exhibited moderate tremor while performing tasks such as writing, drinking, or pouring. Relatives of ET patients are five times more likely to develop the disease than are members of the population and ten times more likely if the proband's tremor began at an early age. The majority of the affected relatives can expect to experience impairment resulting from tremor.

Teaching videotapes, developed to aid in the evaluation of several movement disorders, have not been used in essential tremor research. As part of the Washington Heights‐Inwood Genetic Study of Essential Tremor (WHIGET), we developed a reliable and valid tremor rating scale. Because this rating scale is currently being used by investigators at other centers, we developed a teaching videotape to aid in the consistent application of this scale. OBJECTIVE To develop a teaching videotape for a revised version of the WHIGET Tremor Rating Scale and to assess the interrater agreement among raters who used this videotape to rate tremor. METHODS The revised WHIGET Tremor Rating Scale was used to rate action tremor from 0 to 4 during six tests: arm extension, pouring, drinking, using a spoon, finger‐to‐nose, and drawing spirals. A 22‐minute teaching videotape was developed that includes a 29‐item educational section and a self‐assessment section consisting of 20 examples of tremor ratings chosen by the two WHIGET study neurologists. Eight raters, including senior movement disorder specialists, movement disorder fellows, general neurologists, and a movement disorder nurse practitioner, independently viewed the videotape and rated tremor during the self‐assessment section. Interobserver reliability was assessed with weighted kappa statistics (κw). RESULTS Eight raters each rated 20 items (160 ratings total). Total κw was 0.97 (nearly perfect agreement). Interrater reliability was as follows: κw = 0.99 (movement disorder specialists), κw = 0.98 (movement disorder fellows), and κw = 0.97 (general neurologists); all κw were nearly perfect. CONCLUSIONS This teaching videotape may be used to improve the uniform application of the revised WHIGET Tremor Rating Scale by raters with various levels of experience in movement disorders. Mov. Disord. 16:89–93, 2001. © 2001 Movement Disorder Society.

Essential tremor is not a homogeneous condition. There are differences in age of onset, anatomic distribution of tremor, and rate of progression. The ET in several groups of patients in this study (those with age of onset >60 years and those without head tremor) progressed more rapidly, suggesting that these ET cases may define distinct clinical subtypes. These subtypes should be further assessed for etiologic and genetic heterogeneity as well as differences in responsiveness to therapeutic agents. Arch Neurol. 2000;57:1194-1198

A number of tremorogenic β-carboline alkaloids have been found in common plant-derived foodstuffs, beverages, and inhaled substances. Because of their natural presence in the food chain, there is a growing concern regarding the potential risks of certain essen tial tremors associated with the long-term low-level dietary exposure to these alkaloids. The purpose of this study was to develop an effective analytical method to determine blood levels of two major β-car boline derivatives, harmane and harmine. Human blood was extracted with ethyl acetate and methyl-tbutyl ether (2:98) under an alkaline condition. After evaporation of organic solvent, the samples were re-constructed in methanol. The samples were fraction ated on a 250 × 4.6-mm C18 reversed-phase column with an isocratic mobile system consisting of 17.5 mM potassium phosphate buffer (ph 6.5) and methanol (30: 70), followed by an on-line fluorescence detection. The method had the detection limit to determine 206 and 81 pg/ml of harmane and harmine, respectively, in 10 ml of human blood. The intraday precision (C.V.) at 25 ng/ml was less than 6.7 and 3.4% for harmane and harmine, respectively. The interday precision was 7.3% for harmane and 5.4% for harmine. The method has proven sensitive, reproducible, and thus useful for both laboratory and clinical studies of β-carboline toxicities.A number of tremorogenic β-carboline alkaloids such as harmane, harmine, harmaline, and ibogaine have been found in common plant-derived foodstuffs (wheat, rice, corn, barley, soybeans, rye, grapes, mushrooms, vinegar). plant -derived beverages (wine. beer. whisky. brandy, sake). and plant-derived inhaled substances (tobacco) (1, 6). These substances are also endogenous to animal tissue (6, 9) and have been isolated in beef and sardines (1). Laboratory animals exposed to these chemicals result in an acute action tremor (5). Because of their natural presence in the food chain, it is conceivable that the route of exposure in humans would be from dietary sources, smoking. and consumption of alcoholic beverages. In fact, the occurrence of β-carbo-lines in human blood under normal physiological Copyright © 2000 by Academic Press All rights of reproduction in any form reserved. Rommelspacher et al. employed thin-layer gel-plate separation and mul tiple extraction followed by high-performance liquid chromatography (HPLC) to detect 6-0H-tetrahydronorharmane (6-0H-THN) in rat and human sam ples (9). The substantial precolumn preparation in that study limited its application to clinical monitoring of this and other β-carbolines. Moncrieff also reported an HPLC method for tissue harmane, harmine, and harmaline (4). However, the quantitation of three compounds required three different mobile phases and three separate HPLC runs. A better HPLC method was developed by Adachi et al.(1) for determination norharmane and harmane in foodstuffs. Nevertheless, the adaptability of this method to biological remains uncertain. Moreover, to the best of our knowledge, there has been no report ...

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