title: Assessing the perception of trunk movements in military personnel with chronic non-specific low back pain using a virtual mirror.
abstract: Chronic pain, including chronic non-specific low back pain (CNSLBP), is often associated with body perception disturbances, but these have generally been assessed under static conditions. The objective of this study was to use a "virtual mirror" that scaled visual movement feedback to assess body perception during active movement in military personnel with CNSLBP (n = 15) as compared to military healthy control subjects (n = 15). Subjects performed a trunk flexion task while sitting and standing in front of a large screen displaying a full-body virtual mirror-image (avatar) in real-time. Avatar movements were scaled to appear greater, identical, or smaller than the subjects' actual movements. A total of 126 trials with 11 different scaling factors were pseudo-randomized across 6 blocks. After each trial, subjects had to decide whether the avatar's movements were "greater" or "smaller" than their own movements. Based on this two-alternative forced choice paradigm, a psychophysical curve was fitted to the data for each subject, and several metrics were derived from this curve. In addition, task adherence (kinematics) and virtual reality immersion were assessed. Groups displayed a similar ability to discriminate between different levels of movement scaling. Still, subjects with CNSLBP showed an abnormal performance and tended to overestimate their own movements (a right-shifted psychophysical curve). Subjects showed adequate task adherence, and on average virtual reality immersion was reported to be very good. In conclusion, these results extend previous work in patients with CNSLBP, and denote an important relationship between body perception, movement and pain. As such, the assessment of body perception during active movement can offer new avenues for understanding and managing body perception disturbances and abnormal movement patterns in patients with pain.
authors: Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS), Québec, Québec, Canada.
authors: Meyke
authors: M
authors: Roosink
authors: Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS), Québec, Québec, Canada; Department of Rehabilitation, Faculty of Medicine, Laval University, Québec, Québec, Canada.
authors: Bradford J
authors: BJ
authors: McFadyen
authors: Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS), Québec, Québec, Canada; Department of Rehabilitation, Faculty of Medicine, Laval University, Québec, Québec, Canada; Canadian Forces Health Services Group Headquarters, Directorate of Medical Policy (Physiotherapy), Valcartier Garrison, Québec, Québec, Canada; Department of Radiology, Faculty of Medicine, Laval University, Québec, Québec, Canada.
authors: Luc J
authors: LJ
authors: Hébert
authors: Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS), Québec, Québec, Canada; School of Psychology, Laval University, Québec, Québec, Canada.
authors: Philip L
authors: PL
authors: Jackson
authors: Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS), Québec, Québec, Canada; Department of Rehabilitation, Faculty of Medicine, Laval University, Québec, Québec, Canada.
authors: Laurent J
authors: LJ
authors: Bouyer
authors: Centre Interdisciplinaire de Recherche en Réadaptation et Intégration Sociale (CIRRIS), Québec, Québec, Canada; Department of Rehabilitation, Faculty of Medicine, Laval University, Québec, Québec, Canada.
authors: Catherine
authors: C
authors: Mercier
mesh_terms: D000328:Adult; D001416:Back Pain / Q000503:physiopathology*; D016022:Case-Control Studies; D025461:Feedback, Physiological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009039:Motion Perception; D009068:Movement; D011434:Proprioception; D060726:Torso / Q000502:physiology / Q000503:physiopathology; D014584:User-Computer Interface