The following is a summary of “Extensive Sensorimotor Training Predetermines Central Pain Changes During the Development of Prolonged Muscle Pain,” published in the June 2023 issue of Pain by Zamorano et al.
The overloading of musculoskeletal structures partially explains why repetitive movements (RM) are a significant risk factor for musculoskeletal discomfort. RM may also induce brain plasticity, resulting in maladaptive alterations in sensorimotor regions and altered pain processing. This study sought to determine whether musicians who engage in extensive RM exhibit changed brain processing in response to prolonged experimental muscle pain. About 19 healthy musicians and 20 non-trained controls participated in 3 sessions (Days 1-3-8). In each session, event-related potentials (ERPs) were recorded in response to non-nociceptive external and nociceptive intraepidermal electrical stimulation and reaction latencies, electrical detection thresholds, and pressure pain thresholds (PPTs); after Day 1, an intramuscular injection of nerve growth factor (NGF) into the right first dorsal interosseous muscle induced prolonged muscle pain in all participants.
On a numeric rating scale (NRS), the pain intensity of musicians was lower than that of non-musicians (P<.007). In addition, the greater the quantity of weekly training, the lower the NRS pain scores on Days 3 through 8 (P<.037). In comparison to Day 1, NGF decreased PPTs on Days 3 through 8 (P< .001) and non-nociceptive P200 and P300 ERP amplitudes on Day 8 (P<.044) in both groups. In comparison to controls, musicians demonstrated secondary hyperalgesia to electrical stimulation on Day 3 to 8 (P<.004) and decreased nociceptive P200 ERP amplitudes on Day 8 (P< .05). ERP components correlated with pain detection reaction times, sensitivity (PPTs and electrical detection thresholds), and severity (NRS) across all participants (all P <.043).
These findings demonstrate that repetitive sensorimotor training alters the brain’s chronic pain processing, biasing the cortical response to nociceptive inputs. Sensorimotor training may increase the sensitivity to nociceptive inputs during the development of chronic muscle pain. These novel findings demonstrate that repetitive sensorimotor practice is a source of interindividual variation in central pain processing.