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Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor
BACKGROUND: Drawing Archimedes spirals is a popular and valid method of assessing action tremor in the upper limbs. We performed the first blinded comparison of Fahn–Tolosa–Marín (FTM) ratings and tablet measures of essential tremor to determine if a digitizing tablet is better than 0–4 ratings in d...
Autores principales: | , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Columbia University Libraries/Information Services
2017
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618112/ https://www.ncbi.nlm.nih.gov/pubmed/28966878 http://dx.doi.org/10.7916/D89S20H7 |
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author | Elble, Rodger J Ellenbogen, Aaron |
author_facet | Elble, Rodger J Ellenbogen, Aaron |
author_sort | Elble, Rodger J |
collection | PubMed |
description | BACKGROUND: Drawing Archimedes spirals is a popular and valid method of assessing action tremor in the upper limbs. We performed the first blinded comparison of Fahn–Tolosa–Marín (FTM) ratings and tablet measures of essential tremor to determine if a digitizing tablet is better than 0–4 ratings in detecting changes in essential tremor that exceed random variability in tremor amplitude. METHODS: The large and small spirals of FTM were drawn with each hand on two consecutive days by 14 men and four women (age 60±8.7 years [mean±SD]) with mild to severe essential tremor. The drawings were simultaneously digitized with a digitizing tablet. Tremor in each digitized drawing was computed with spectral analysis in an independent laboratory, blinded to the clinical ratings. The mean peak-to-peak tremor displacement (cm) in the four spirals and mean FTM ratings were compared statistically. RESULTS: Test–retest intraclass correlations (ICCs) (two-way random single measures, absolute agreement) were excellent for the FTM ratings (ICC 0.90, 95% CI 0.76–0.96) and tablet (ICC 0.97, 95% CI 0.91–0.99). Log(10) tremor amplitude (T) and FTM were strongly correlated (logT=αFTM + β, α≈0.6, β≈–1.27, r=0.94). The minimum detectable change for the tablet and FTM were 51% and 67% of the initial assessment. DISCUSSION: Digitizing tablets are much more precise than clinical ratings, but this advantage is mitigated by the natural variability in tremor. Nevertheless, the digitizing tablet is a robust method of quantifying tremor that can be used in lieu of or in combination with clinical ratings. |
format | Online Article Text |
id | pubmed-5618112 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Columbia University Libraries/Information Services |
record_format | MEDLINE/PubMed |
spelling | pubmed-56181122017-09-29 Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor Elble, Rodger J Ellenbogen, Aaron Tremor Other Hyperkinet Mov (N Y) Brief Reports BACKGROUND: Drawing Archimedes spirals is a popular and valid method of assessing action tremor in the upper limbs. We performed the first blinded comparison of Fahn–Tolosa–Marín (FTM) ratings and tablet measures of essential tremor to determine if a digitizing tablet is better than 0–4 ratings in detecting changes in essential tremor that exceed random variability in tremor amplitude. METHODS: The large and small spirals of FTM were drawn with each hand on two consecutive days by 14 men and four women (age 60±8.7 years [mean±SD]) with mild to severe essential tremor. The drawings were simultaneously digitized with a digitizing tablet. Tremor in each digitized drawing was computed with spectral analysis in an independent laboratory, blinded to the clinical ratings. The mean peak-to-peak tremor displacement (cm) in the four spirals and mean FTM ratings were compared statistically. RESULTS: Test–retest intraclass correlations (ICCs) (two-way random single measures, absolute agreement) were excellent for the FTM ratings (ICC 0.90, 95% CI 0.76–0.96) and tablet (ICC 0.97, 95% CI 0.91–0.99). Log(10) tremor amplitude (T) and FTM were strongly correlated (logT=αFTM + β, α≈0.6, β≈–1.27, r=0.94). The minimum detectable change for the tablet and FTM were 51% and 67% of the initial assessment. DISCUSSION: Digitizing tablets are much more precise than clinical ratings, but this advantage is mitigated by the natural variability in tremor. Nevertheless, the digitizing tablet is a robust method of quantifying tremor that can be used in lieu of or in combination with clinical ratings. Columbia University Libraries/Information Services 2017-07-07 /pmc/articles/PMC5618112/ /pubmed/28966878 http://dx.doi.org/10.7916/D89S20H7 Text en © 2017 Elble et al. http://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution–Noncommerical–No Derivatives License, which permits the user to copy, distribute, and transmit the work provided that the original author and source are credited; that no commercial use is made of the work; and that the work is not altered or transformed. |
spellingShingle | Brief Reports Elble, Rodger J Ellenbogen, Aaron Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor |
title | Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor |
title_full | Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor |
title_fullStr | Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor |
title_full_unstemmed | Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor |
title_short | Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor |
title_sort | digitizing tablet and fahn–tolosa–marín ratings of archimedes spirals have comparable minimum detectable change in essential tremor |
topic | Brief Reports |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618112/ https://www.ncbi.nlm.nih.gov/pubmed/28966878 http://dx.doi.org/10.7916/D89S20H7 |
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