Moving in an environment of induced sensorimotor incongruence does not influence pain sensitivity in healthy volunteers: a randomised within-subject experiment.
OBJECTIVE
It has been proposed that in the same way that conflict between vestibular and visual inputs leads to motion sickness, conflict between motor commands and sensory information associated with these commands may contribute to some chronic pain states. Attempts to test this hypothesis by artificially inducing a state of sensorimotor incongruence and assessing self-reported pain have yielded equivocal results. To help clarify the effect sensorimotor incongruence has on pain we investigated the effect of moving in an environment of induced incongruence on pressure pain thresholds (PPT) and the pain experienced immediately on completion of PPT testing.


METHODS
Thirty-five healthy subjects performed synchronous and asynchronous upper-limb movements with and without mirror visual feedback in random order. We measured PPT over the elbow and the pain evoked by testing. Generalised linear mixed-models were performed for each outcome. Condition (four levels) and baseline values for each outcome were within-subject factors.


RESULTS
There was no effect of condition on PPT (p = 0.887) or pressure-evoked pain (p = 0.771). A sensitivity analysis using only the first PPT measure after each condition confirmed the result (p = 0.867).


CONCLUSIONS
Inducing a state of movement related sensorimotor incongruence in the upper-limb of healthy volunteers does not influence PPT, nor the pain evoked by testing. We found no evidence that sensorimotor incongruence upregulates the nociceptive system in healthy volunteers.
School of Physiotherapy, The University of Notre Dame Australia, Fremantle, Western Australia, Australia.
Benedict Martin
BM
Wand
Floreat Physiotherapy, Floreat, Western Australia, Australia.
Lareina
L
Szpak
School of Physiotherapy, The University of Notre Dame Australia, Fremantle, Western Australia, Australia.
Pamela J
PJ
George
Institute for Health Research, The University of Notre Dame Australia, Fremantle, Western Australia, Australia.
Max K
MK
Bulsara
Centre for Research in Rehabilitation, School of Health Sciences and Social Care, Brunel University, Uxbridge, United Kingdom.
Neil Edward
NE
O'Connell
The Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia.
G Lorimer
GL
Moseley
D000293:Adolescent; D000328:Adult; D059350:Chronic Pain / Q000503:physiopathology*; D056228:Feedback, Sensory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009041:Motion Sickness / Q000503:physiopathology*; D034941:Upper Extremity / Q000503:physiopathology