title: Factors associated with the modulation of pain by visual distortion of body size.
abstract: Modulation of pain using visual distortion of body size (VDBS) has been the subject of various reports. However, the mechanism underlying the effect of VDBS on pain has been less often studied. In the present study, factors associated with modulation of pain threshold by VDBS were investigated. Visual feedback in the form of a magnified image of the hand was provided to 44 healthy adults to examine changes in pain. In participants with a higher pain threshold when visual feedback of a magnified image of the hand was provided, the two-point discrimination threshold decreased. In contrast, participants with a lower pain threshold with visual feedback of a magnified image of the hand experienced unpleasant emotions toward the magnified image of the hand. Interestingly, this emotional reaction was strongly associated with negative body consciousness in several subjects. These data suggested an analgesic effect of visual feedback in the form of a magnified image of the hand is only when tactile perception is vivid and the emotional reaction toward the magnified image is moderate. The results also suggested that negative body consciousness is important for the modulation of pain using VDBS.
authors.affiliation: Department of Neurorehabilitation, Graduate School of Health Science, Kio University Nara, Japan ; Neurocognitive Rehabilitation Center, Setsunan General Hospital Osaka, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Osumi
authors.affiliation: Department of Neurorehabilitation, Graduate School of Health Science, Kio University Nara, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Imai
authors.affiliation: Department of Neurorehabilitation, Graduate School of Health Science, Kio University Nara, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Ueta
authors.affiliation: Department of Neurorehabilitation, Graduate School of Health Science, Kio University Nara, Japan ; Japan Society for the Promotion of Science Tokyo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakano
authors.affiliation: Department of Neurorehabilitation, Graduate School of Health Science, Kio University Nara, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nobusako
authors.affiliation: Department of Neurorehabilitation, Graduate School of Health Science, Kio University Nara, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Morioka
keywords: body consciousness; body representation; distortion of body size; illusion; mirror visual feedback; pain