Does a screening questionnaire for essential tremor agree with the physician's examination?

Abstract

In research studies of essential tremor (ET), monetary and geographic factors often necessitate diagnosis by interview rather than by examination. Few attempts have been made to determine the validity of a screening instrument for ET. A total of 242 subjects (33 definite or probable ET, 54 possible ET, and 155 normal) were part of a community-based family study of ET in northern Manhattan. Subjects underwent a tremor interview and videotaped tremor examination. The interview included 12 screening questions for ET. Two neurologists rated the severity of tremor on videotape and assigned diagnoses. The subjects' responses to the 12 screening questions were compared with the neurologic examination and the neurologists' diagnoses. There was an association between the number of affirmative responses on the 12-item screen and the severity of tremor during the videotaped tremor examination (r = 0.66, p < 0.01). Including those with probable and definite ET and defining a positive screen result as an affirmative response to at least 1 of 12 screening questions, the sensitivity of the screening questionnaire was 73%, the specificity was 96%, and the positive predictive value was 80%. The responses to the questionnaire closely correlated with the severity of tremor on neurologic examination. The questionnaire had moderate validity for subjects with probable or definite ET; subjects with mild ET often screened negative. Hence, in population-based studies and family studies of ET, it is important to examine all subjects for the presence of mild asymptomatic ET.

Senile Tremor

“…The 12-item screen demonstrated moderate validity in terms of distinguishing normal subjects from those with probable or definite ET (sensitivity = 73%, specificity = 96%, positive predictive value = 80%) [10]. In addition, the interviewer collected demographic information, and information by the patient's report on the presence of concurrent medical conditions (including arthritis, hypertension, heart disease, thyroid disease, emphysema, diabetes mellitus, kidney failure), medications, distribution and severity of tremor, effects of alcohol, cigarettes and caffeine, effectiveness of tremor medications, change in tremor with activity or rest, and specific functional impairments resulting from tremor [7,8].…”

“…Diagnostic criteria have been published previously [7,8,10]. Briefly, diagnoses of definite ET required: (1) postural tremor rated as +2; (2) kinetic tremor rated as +2 during four tests, and (3) tremor that by history interfered with at least one activity of daily living.…”

Elevated blood harmane (1-methyl-9H-pyrido[3,4-b]indole) concentrations in essential tremor

“…The diagnosis of ET was confirmed by Dr. Louis using published diagnostic criteria (moderate or greater amplitude tremor during three activities or a head tremor in the absence of PD, dystonia or another neurological disorder) (Louis et al, 1998a;Louis et al, 1997;Louis et al, 2002b). None of the cases or control subjects had PD or dystonia.…”

Blood harmane concentrations and dietary protein consumption in essential tremor

“…The tester videotaped a tremor examination in all participants, 29,30 and each of 12 videotaped action tremor items was rated (E.D.L.) on a scale from 0 to 3, resulting in a total tremor score (range = 0 to 36 [maximum]).…”

“…The diagnosis of ET was confirmed by the rater using published diagnostic criteria (moderate amplitude tremor during three activities or a head tremor) and diagnostic gradations of possible, probable, and definite ET. 29,30 None of the patients or control subjects had PD or dystonia.…”