Motor adaptation varies between individuals in the transition to sustained pain. Issue 9 (September 2019)

• Record Type: Journal Article
• Authors: Summers, Simon J.; Chipchase, Lucy S.; Hirata, Rogerio; Graven-Nielsen, Thomas; Cavaleri, Rocco; Schabrun, Siobhan M.
• Is Part Of: Pain. Volume 160:Issue 9(2019)
• Publication Date: 2019-09
• Subjects: Motor cortex plasticity -- Musculoskeletal pain -- Transcranial magnetic stimulation -- Motor variability -- Motor adaptation; Pain -- Periodicals; Douleur -- Périodiques; Anesthésie -- Périodiques; Pain; Electronic journals; Periodicals; Electronic journals; 616.0472
• DOI: 10.1097/j.pain.0000000000001604
• Languages: English
• ISSNs: 0304-3959

Abstract

Abstract : Abstract: Musculoskeletal pain is associated with altered motor control that, despite short-term benefit, is hypothesised to have long-term consequences, contributing to the development of chronic pain. However, data on how motor control is altered when pain is sustained beyond a transient event are scarce. Here, we investigated motor adaptation, and its relationship with corticomotor excitability, in the transition to sustained muscle pain. Twenty-eight healthy individuals were injected with nerve growth factor into the right extensor carpi radialis brevis muscle on days 0 and 2. Motor adaptation and corticomotor excitability were assessed on day −2, before injection on days 0 and 2, and again on days 4 and 14. Motor adaptation was quantified during a radial–ulnar movement as kinematic variability of wrist flexion–extension and pronation–supination, and as electromyographic (EMG) variability of extensor carpi radialis brevis activity. Pain, muscle soreness, and functional limitation were assessed from days 0 to 14. Pain, muscle soreness, and functional limitation were evident at days 2 and 4 ( P < 0.001). Electromyographic variability reduced at days 4 and 14 ( P < 0.04), with no change in kinematic variability ( P = 0.9). However, data revealed variation in EMG and kinematic variability between individuals: some displayed increased motor variability, whereas others a decrease. Individuals who displayed an increase in EMG variability after 4 days of pain also displayed an increase in corticomotor excitability ( r = 0.43, P = 0.034). These findings suggest individual adaptation of the motor system in the transition to sustained pain that could have implications for clinical musculoskeletal pain disorders. Abstract : The movement strategy adopted by an individual in the transition to sustained pain is related to his/her motor cortical strategy, but the strategy differs between individuals.