Consensus Statement on the classification of tremors. from the task force on tremor of the International Parkinson and Movement Disorder Society

Abstract

Background Consensus criteria for classifying tremor disorders were published by the International Parkinson and Movement Disorder Society in 1998. Subsequent advances with regard to essential tremor, tremor associated with dystonia, and other monosymptomatic and indeterminate tremors make a significant revision necessary. Objectives Convene an international panel of experienced investigators to review the definition and classification of tremor. Methods Computerized MEDLINE searches in January 2013 and 2015 were conducted using a combination of text words and MeSH terms: “tremor”, “tremor disorders”, “essential tremor”, “dystonic tremor”, and “classification” limited to human studies. Agreement was obtained using consensus development methodology during four in‐person meetings, two teleconferences, and numerous manuscript reviews. Results Tremor is defined as an involuntary, rhythmic, oscillatory movement of a body part and is classified along two axes: Axis 1—clinical characteristics, including historical features (age at onset, family history, and temporal evolution), tremor characteristics (body distribution, activation condition), associated signs (systemic, neurological), and laboratory tests (electrophysiology, imaging); and Axis 2—etiology (acquired, genetic, or idiopathic). Tremor syndromes, consisting of either isolated tremor or tremor combined with other clinical features, are defined within Axis 1. This classification scheme retains the currently accepted tremor syndromes, including essential tremor, and provides a framework for defining new syndromes. Conclusions This approach should be particularly useful in elucidating isolated tremor syndromes and syndromes consisting of tremor and other signs of uncertain significance. Consistently defined Axis 1 syndromes are needed to facilitate the elucidation of specific etiologies in Axis 2. © 2017 International Parkinson and Movement Disorder Society

Deep brain stimulation in uncommon tremor disorders: indications, targets, and programming

“…Tremor, defined as an involuntary, rhythmic, oscillatory movement of a body part [1] is a key semeiological feature of Parkinson disease (PD) and essential tremor (ET) [2, 3], as well as the cardinal symptom of less common but equally disabling movement disorders, namely Holmes tremor (HT), orthostatic tremor (OT), and fragile X–associated tremor/ataxia syndrome (FXTAS) [1, 4]. In addition, tremor represents a secondary yet disabling feature of immune-mediated neurological disorders such as multiple sclerosis (MS) and demyelinating peripheral neuropathies [1].…”

“…In addition, tremor represents a secondary yet disabling feature of immune-mediated neurological disorders such as multiple sclerosis (MS) and demyelinating peripheral neuropathies [1]. …”

“…HT is a rest, postural, and intention low frequency (<5 Hz) tremor [1] usually associated with an ischemic or demyelinating lesion of the cerebello-thalamo-cortical or dentate-rubro-olivary pathways, with superimposed nigrostriatal dysfunction [1, 5, 6]. OT is a 13-18 Hz tremor affecting the weight-bearing limbs and resulting in a sensation of unsteadiness and imbalance when standing [1, 4, 7]. Although the exact location of its generator remains unclear, available evidence suggests the involvement of the cerebellum and pons [7, 8].…”

Changes in Midline Tremor and Gait Following Deep Brain Stimulation for Essential Tremor

“…Seven persons with ET and 17 persons with ET plus (due to the presence of ET and tandem gait impairment 14 ) participated (mean±standard deviation age: 68 ± 6 years, sex: 16M/8F). ET diagnosis was confirmed by standardized criteria 14 and evaluation by a fellowship-trained movement disorders neurologist.…”

Tracking the central and peripheral origin of tremor

“…This notion might help to explain some degrees of clinical heterogeneity of ET (Bhatia et al, 2018) based on the preferential involvement of central vs. peripheral components. In addition, different interventions have diverse effects on each tremor component.…”