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

Abstract

Background: 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.

Objective: To investigate the relationship between motor imagery and phantom limb painful and nonpainful sensations.

Method: 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.

Results: 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.

Conclusions: 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.