Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.

A phantom limb is the sensation that an amputated limb is still attached to the body and is moving together with other body parts. Phantom limb phenomenon is often described on the basis of the patient's subjective sense, for example as represented using a visual analog scale (VAS). The aim of...

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Main Authors: Noritaka Kawashima, Tomoki Mita
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2016-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC4882045?pdf=render
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author Noritaka Kawashima
Tomoki Mita
author_facet Noritaka Kawashima
Tomoki Mita
author_sort Noritaka Kawashima
collection DOAJ
description A phantom limb is the sensation that an amputated limb is still attached to the body and is moving together with other body parts. Phantom limb phenomenon is often described on the basis of the patient's subjective sense, for example as represented using a visual analog scale (VAS). The aim of this study was to propose a novel quantification method for behavioral aspect of phantom limb by psychophysics. Twelve unilateral forearm amputees were asked to perform phantom wrist motion with various motion frequencies (60, 80, 100, 120, 140, 160, 180, 200, 220, 240% of preferred speed). The attainment of phantom limb motion in each session was rated by the VAS ranging from 0 (hard) to 10 (easy). The relationship between the VAS and motion frequency was mathematically fitted by quadric function, and the value of shift and the degree of steepness were obtained as evaluation variables for the phantom limb movement. In order to test whether the proposed method can reasonably quantify the characteristics of phantom limb motion, we compared the variables among three different phantom limb movement conditions: (1) unilateral (phantom only), (2) bimanual, and (3) bimanual wrist movement with mirror reflection-induced visual feedback (MVF). While VAS rating showed a larger extent of inter- and intra-subject variability, the relationship of the VAS in response to motion frequency could be fitted by quadric curve, and the obtained parameters based on quadric function well characterize task-dependent changes in phantom limb movement. The present results suggest the potential usefulness of psychophysical evaluation as a validate assessment tool of phantom limb condition.
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spelling doaj.art-5858a1bf98a84c65a2d405b979123ae62022-12-22T00:16:28ZengPublic Library of Science (PLoS)PLoS ONE1932-62032016-01-01115e015634910.1371/journal.pone.0156349Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.Noritaka KawashimaTomoki MitaA phantom limb is the sensation that an amputated limb is still attached to the body and is moving together with other body parts. Phantom limb phenomenon is often described on the basis of the patient's subjective sense, for example as represented using a visual analog scale (VAS). The aim of this study was to propose a novel quantification method for behavioral aspect of phantom limb by psychophysics. Twelve unilateral forearm amputees were asked to perform phantom wrist motion with various motion frequencies (60, 80, 100, 120, 140, 160, 180, 200, 220, 240% of preferred speed). The attainment of phantom limb motion in each session was rated by the VAS ranging from 0 (hard) to 10 (easy). The relationship between the VAS and motion frequency was mathematically fitted by quadric function, and the value of shift and the degree of steepness were obtained as evaluation variables for the phantom limb movement. In order to test whether the proposed method can reasonably quantify the characteristics of phantom limb motion, we compared the variables among three different phantom limb movement conditions: (1) unilateral (phantom only), (2) bimanual, and (3) bimanual wrist movement with mirror reflection-induced visual feedback (MVF). While VAS rating showed a larger extent of inter- and intra-subject variability, the relationship of the VAS in response to motion frequency could be fitted by quadric curve, and the obtained parameters based on quadric function well characterize task-dependent changes in phantom limb movement. The present results suggest the potential usefulness of psychophysical evaluation as a validate assessment tool of phantom limb condition.http://europepmc.org/articles/PMC4882045?pdf=render
spellingShingle Noritaka Kawashima
Tomoki Mita
Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.
PLoS ONE
title Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.
title_full Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.
title_fullStr Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.
title_full_unstemmed Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.
title_short Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees.
title_sort psychophysical evaluation of the capability for phantom limb movement in forearm amputees
url http://europepmc.org/articles/PMC4882045?pdf=render
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