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Illusory resizing of the painful knee is analgesic in symptomatic knee osteoarthritis

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posted on 2018-09-06, 15:12 authored by Tasha R. Stanton, Helen R. Gilpin, Louisa Edwards, G. Lorimer Moseley, Roger NewportRoger Newport
Background. Experimental and clinical evidence support a link between body represen- tations and pain. This proof-of-concept study in people with painful knee osteoarthritis (OA) aimed to determine if: (i) visuotactile illusions that manipulate perceived knee size are analgesic; (ii) cumulative analgesic effects occur with sustained or repeated illusions. Methods. Participants with knee OA underwent eight conditions (order randomised): stretch and shrink visuotactile (congruent) illusions and corresponding visual, tactile and incongruent control conditions. Knee pain intensity (0-100 numerical rating scale; 0 = no pain at all and 100 D worst pain imaginable) was assessed pre- and post- condition. Condition (visuotactile illusion vs control) × Time (pre-/post-condition) repeated measure ANOVAs evaluated the effect on pain. In each participant, the most beneficial illusion was sustained for 3 min and was repeated 10 times (each during two sessions); paired t -tests compared pain at time 0 and 180s (sustained) and between illusion 1 and illusion 10 (repeated). Results. Visuotactile illusions decreased pain by an average of 7.8 points (95% CI [2.0-13.5]) which corresponds to a 25% reduction in pain, but the tactile only and visual only control conditions did not (Condition × Time interaction: p = 0:028). Visuotactile illusions did not differ from incongruent control conditions where the same visual manipulation occurred, but did differ when only the same tactile input was applied. Sustained illusions prolonged analgesia, but did not increase it. Repeated illusions increased the analgesic effect with an average pain decrease of 20 points (95% CI [6.9-33.1])-corresponding to a 40% pain reduction. Discussion. Visuotactile illusions are analgesic in people with knee OA. Our results suggest that visual input plays a critical role in pain relief, but that analgesia requires multisensory input. That visual and tactile input is needed for analgesia, supports multisensory modulation processes as a possible explanatory mechanism. Further research exploring the neural underpinnings of these visuotactile illusions is needed. For potential clinical applications, future research using a greater dosage in larger samples is warranted.

Funding

Tasha R. Stanton was supported by a Canadian Institute for Health Research Postdoctoral Training Fellowship (ID223354) and a National Health & Medical Research Council Early Career Fellowship (ID1054041). G. Lorimer Moseley was supported by a National Health and Medical Research Council Research Fellowship (ID1061279). This work was supported by a University of South Australia Internal Research Grant.

History

School

  • Sport, Exercise and Health Sciences

Published in

PeerJ

Volume

2018

Issue

7

Citation

STANTON, T.R. ... et al, 2018. Illusory resizing of the painful knee is analgesic in symptomatic knee osteoarthritis. PeerJ, 6, e5206.

Publisher

PeerJ © Stanton et al.

Version

  • VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Acceptance date

2018-06-20

Publication date

2018

Notes

This is an Open Access Article. It is published by PeerJ under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

eISSN

2167-8359

Language

  • en