Faulty proprioceptive information disrupts motor imagery – an experimental study

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McCormick K(a), Zalucki N(a), Hudson ML(a), Moseley GL(a,b)
(a) Univ Queensland, St Lucia, Qld 4067 Australia
(b) Univ Oxford, Dept Physiol Anat & Genet, Oxford OX1 3QX, England

Question: Does faulty proprioceptive input disrupt the internal model of the body that the brain uses to control movement?

Design: Randomised, within-participant experimental study.

Participants: Twenty-two (13 F) healthy adults.

Intervention: Participants performed a motor imagery task that involved making left/right judgements of pictured right and left hands in 16 different postures under five conditions involving stimuli being applied to the experimental (L) hand. The five conditions were: vibration (of the wrist extensor tendons to elicit the illusion of wrist flexion), sham (vibration of the ulna styloid), active flexion, passive flexion, and control (no stimulus).

Outcome measures: Accuracy and response time of the control (R) hand in making left/right judgements of the pictures.

Results: Response time during vibration was longer for those who reported the illusion of wrist flexion (n = 18) than for those who did not (p < 0.01) whereas accuracy was unaffected (p = 0.71). In those who reported the illusion, accuracy was unaffected by condition, hand or picture (p > 0.21). Response time during vibration was 910 ms longer (95% CI 730 to 1090) for pictures of the experimental (L) hand (mean 2731 ms, 95% CI 2543 to 2918) than it was for pictures of the control (R) hand (mean 1822 ms, 95% CI 1634 to 2009), and similar to 580 ms longer (95% CI 380 to 785) for pictures of either hand during any other condition (p <0.025).

Conclusion: Faulty proprioceptive input disrupted this motor imagery task, which suggests it can disrupt the model of the limb that the brain uses for movement.

See full article at Aus J Physioth 53: 41-5