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Slow Orthostatic Tremor: Review of the Current Evidence

BACKGROUND: Orthostatic tremor (OT) is defined as tremor in the legs and trunk evoked during standing. While the classical description is tremor of ≥13 Hz, slower frequencies are recognized. There is disagreement as to whether the latter represents a slow variant of classical OT, or different tremor...

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Autores principales: Hassan, Anhar, Caviness, John
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Columbia University Libraries/Information Services 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6886496/
https://www.ncbi.nlm.nih.gov/pubmed/31832265
http://dx.doi.org/10.7916/tohm.v0.721
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author Hassan, Anhar
Caviness, John
author_facet Hassan, Anhar
Caviness, John
author_sort Hassan, Anhar
collection PubMed
description BACKGROUND: Orthostatic tremor (OT) is defined as tremor in the legs and trunk evoked during standing. While the classical description is tremor of ≥13 Hz, slower frequencies are recognized. There is disagreement as to whether the latter represents a slow variant of classical OT, or different tremor disorder(s) given frequent coexistent neurological disease. METHODS: A systematic literature search of PubMed was performed in February 2019 for “slow orthostatic tremor” and related terms which generated 573 abstracts, of which 61 were included. RESULTS: Between 1970 and 2019, there were 70 cases of electrophysiologically confirmed slow OT. Two-thirds were female, of mean age 60 years (range 26–86), and mean disease duration 6 years (range 0–32). One-third of cases were isolated, and two-thirds had a coexistent disorder(s), including parkinsonism (30%), ataxia (12%), and dystonia (10%). Postural arm tremor was present in 34%. Median tremor frequency was 6–7 Hz (range 3–12). Tremor bursts ranged from 50 to 150 ms duration, and were alternating or synchronous in antagonistic and/or analogous muscles. Low and high coherences were reported. Five cases (7%) had coexistent classical OT. Clonazepam was the most effective medication across all frequencies, and levodopa was effective for 4–7 Hz OT with coexistent parkinsonism. Two cases resolved with the treatment of Graves’ disease. Electrophysiology and imaging predominantly support a central tremor generator. DISCUSSION: While multiple lines of evidence separate slow OT from classical OT, clinical and electrophysiological overlap may occur. Primary and secondary causes are identified, similar to classical OT. Further exploration to clarify these slow OT subtypes, clinically and neurophysiologically, is proposed.
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spelling pubmed-68864962019-12-12 Slow Orthostatic Tremor: Review of the Current Evidence Hassan, Anhar Caviness, John Tremor Other Hyperkinet Mov (N Y) Reviews BACKGROUND: Orthostatic tremor (OT) is defined as tremor in the legs and trunk evoked during standing. While the classical description is tremor of ≥13 Hz, slower frequencies are recognized. There is disagreement as to whether the latter represents a slow variant of classical OT, or different tremor disorder(s) given frequent coexistent neurological disease. METHODS: A systematic literature search of PubMed was performed in February 2019 for “slow orthostatic tremor” and related terms which generated 573 abstracts, of which 61 were included. RESULTS: Between 1970 and 2019, there were 70 cases of electrophysiologically confirmed slow OT. Two-thirds were female, of mean age 60 years (range 26–86), and mean disease duration 6 years (range 0–32). One-third of cases were isolated, and two-thirds had a coexistent disorder(s), including parkinsonism (30%), ataxia (12%), and dystonia (10%). Postural arm tremor was present in 34%. Median tremor frequency was 6–7 Hz (range 3–12). Tremor bursts ranged from 50 to 150 ms duration, and were alternating or synchronous in antagonistic and/or analogous muscles. Low and high coherences were reported. Five cases (7%) had coexistent classical OT. Clonazepam was the most effective medication across all frequencies, and levodopa was effective for 4–7 Hz OT with coexistent parkinsonism. Two cases resolved with the treatment of Graves’ disease. Electrophysiology and imaging predominantly support a central tremor generator. DISCUSSION: While multiple lines of evidence separate slow OT from classical OT, clinical and electrophysiological overlap may occur. Primary and secondary causes are identified, similar to classical OT. Further exploration to clarify these slow OT subtypes, clinically and neurophysiologically, is proposed. Columbia University Libraries/Information Services 2019-11-26 /pmc/articles/PMC6886496/ /pubmed/31832265 http://dx.doi.org/10.7916/tohm.v0.721 Text en © 2019 Hassan A, Caviness J. https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution–Noncommercial–No Derivatives License, which permits the user to copy, distribute, and transmit the work provided that the original authors and source are credited; that no commercial use is made of the work; and that the work is not altered or transformed.
spellingShingle Reviews
Hassan, Anhar
Caviness, John
Slow Orthostatic Tremor: Review of the Current Evidence
title Slow Orthostatic Tremor: Review of the Current Evidence
title_full Slow Orthostatic Tremor: Review of the Current Evidence
title_fullStr Slow Orthostatic Tremor: Review of the Current Evidence
title_full_unstemmed Slow Orthostatic Tremor: Review of the Current Evidence
title_short Slow Orthostatic Tremor: Review of the Current Evidence
title_sort slow orthostatic tremor: review of the current evidence
topic Reviews
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6886496/
https://www.ncbi.nlm.nih.gov/pubmed/31832265
http://dx.doi.org/10.7916/tohm.v0.721
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