Lack of complex motor imagery ability and phantom limb pain: A surrogate for motor cortex plasticity reserve?

Abstract

Individuals with amputation have a high prevalence of painful (PLP) and nonpainful limb sensations over a lifetime, and it has been suggested that phantom limb phenomena interfere with motor imagery ability because of loss of afferent information and brain reorganization. To investigate the relationship between motor imagery and phantom limb painful and nonpainful sensations. Detailed data from 15 transradial amputees evaluated in the MeganePro project were acquired. The data collected were the motor imagery ability scores assessed using the Vividness of Movement Imagery Questionnaire-2 and PLP and painful limb sensations measures. A significant positive correlation was found between total external visual imagery score and phantom pain magnitude (r = 0.60, p = 0.01). In particular, a larger and stronger significant positive correlation was observed between the external visual imagery of the complex tasks, running (r = 0.57, p = 0.02), jumping sideways (r = 0.55, p = 0.03), and running downhill (r = 0.65, p = 0.001). In addition, a significant positive correlation was found between external and internal visual imagery scores corresponding to the activity "swinging on a rope" and phantom limb sensation average. Our findings suggest a potential protective effect against PLP in subjects with the ability for more complex types of motor imagery, thus suggesting this modality of imagery may be a surrogate for better motor engagement and plasticity that would be protective against PLP, indicating that subjects with stronger motor cortex plasticity reserve would be protected against PLP.