What is Essential Tremor?

Abstract

Classic essential tremor is a clinical syndrome of action tremor in the upper limbs (at least 95% of patients) and less commonly the head, face/jaw, voice, tongue, trunk, and lower limbs, in the absence of other neurologic signs. However, the longstanding notion of that essential tremor is a monosymptomatic tremor disorder is being challenged by a growing literature describing associated disturbances of tandem walking, personality, mood, hearing and cognition. There is also epidemiologic, pathologic and genetic evidence that essential tremor is pathophysiologically heterogeneous. Misdiagnosis of essential tremor is common because clinicians frequently overlook other neurologic signs and because action tremor in the hands is caused by many conditions, including dystonia, Parkinson disease and drug-induced tremor. Thus, essential tremor is nothing more than a syndrome of idiopathic tremulousness, and the challenge for researchers and clinicians is to find specific etiologies of this syndrome.

Essential pitfalls in “essential” tremor

“…ET has been viewed as a single but heterogeneous disorder ( A , model adapted from Louis et al 60 ) and as an “isolated action tremor syndrome” encompassing other movement disorders ( B ; accounting for cases where “classic ET is too narrowly defined” 61 ). An alternative model ( C , brought to the fore in the reclassification effort for dystonia 53 ) relies on the phenomenological characterization of tremor as a movement presented in isolation or in combination with other movement disorders.…”

Non-Linear EMG Parameters for Differential and Early Diagnostics of Parkinson’s Disease

“…There is a large body of papers on comparative studies of PD and ET (5). However, a diagnostic tool to differentiate these two pathologies is yet to be elaborated (6). …”

Essential tremor versus Parkinson disease

“…Men and women are equally affected. 3,5 ■ Etiology and risk factors associated with ET The etiology of ET is unclear, but there is certainly a familial and genetic component. 4 Researchers estimate that 4% to 5% of the population is diagnosed between ages 40 to 60, while the rate increases for people over age 60.…”