Clinical features of essential tremor
Dragasević, N.; Filipović, S.; Svetel, M.; Milanović, S.; Kostić, V.S.
Srpski Arhiv Za Celokupno Lekarstvo 127(9-10): 301-304
1999
ISSN/ISBN: 0370-8179 PMID: 10649898 Document Number: 511055
Essential tremor is a dominant hereditary disorder with incomplete penetration manifested in action, postural tremor with no signs of parkinsonism, cerebellar lesions or other neurological signs [1]. The diagnosis of essential tremor is established on the basis of the clinical picture, and is greatly variable and insufficiently defined [5]. The study concerned patients with the diagnosis of essential tremor established by the International Association for Tremor Studies in 1995 where tremor was classified into definite++, possible and probable [6]. All patients were subjected to a special questionnaire including demographic and clinical characteristics of tremor. Detailed neurological examinations focusing the presence of extrapyramidal signs were carried out. Fischer's Exact test was used for statistical analysis. The study comprised 107 patients (55 males, 41 females), aged 17-84 years (57.3 +/- 15.6) and 7-77 (46.3 +/- 17.9) at onset of the disease. Postural tremor was present in 36% of patients, postural tremor with intentional deterioration in 16%, statopostural tremor in 21% and continuous tremor in 17% of subjects. Extrapyramidal signs were present in 31% of patients, and clumsiness in fine alternating movements was present in 17 patients. The patients with longer duration of illness were significantly more clumsy in fine alternating movements (Fischer's Exact test; p = 0.507 < 0.05), but not in the presence of extrapyramidal signs (Fischer's Exact test; p = 0.507 > 0.05). Essential tremor is described as a dominant inherited postural tremor. Koller et al. [9] describe dominantly kinetic tremor occurring with movements, while Martinelli et al. [10] describe continuous tremor manifested at rest, posture and with movements. Static tremor was considered as a result of the disease progression [8]. In our patients those with longer duration of the disease were frequently more clumsy in fine alternating movements, but not in manifestation of extrapyramidal signs. Continuous tremor is probably a subgroup of essential tremor; suggests a more pronounced role of cerebellum in its genesis.