Phantom limb pain after unilateral arm amputation is associated with decreased heat pain thresholds in the face

Pain Pressure Threshold as a Non-Linear Marker of Neural Adaptation in Amputees: Evidence from the DEFINE Cohort

BACKGROUND

Amputation poses significant physical, psychological, and emotional challenges, with chronic pain being one of the most debilitating outcomes. Pain Pressure Threshold (PPT), a measure of nociceptive sensitivity, is a valuable tool for assessing changes in pain perception. Understanding PPT modulation in amputees is crucial for uncovering the mechanisms underlying pain and developing targeted interventions for pain management.

OBJECTIVE

This study aimed to evaluate PPT in amputees and identify factors associated with PPT variation in this population.

METHODS

This cross-sectional study analyzed neurophysiological, clinical, and demographic data from 86 amputee patients. PPT was assessed as the primary outcome, and its associations with demographic and clinical predictors were examined using both linear and quadratic regression models.

RESULTS

Multivariate analysis identified a significant association between PPT and biological sex, with females exhibiting lower PPT values than males. Quadratic regression analyses revealed inverted U-shaped associations between PPT and age, BMI, and duration since amputation. PPT increased with age, peaking at 45.8 years, followed by a decline. Similar patterns were observed for BMI, peaking at 27.0 kg/m2, and for amputation duration, peaking at 26.6 months.

CONCLUSIONS

Our findings indicate that sex, age, BMI, and time since amputation are significant factors influencing PPT in amputees, with nonlinear relationships observed for age, BMI, and amputation duration. These results suggest that physiological and disease-related factors (such as age, BMI, and duration of injury) have specific peaks for optimal PPT, highlighting their role in the brain's compensatory system and potential implications for targeted pain management strategies.

Advances in targeting central sensitization and brain plasticity in chronic pain

Maladaptation in sensory neural plasticity of nociceptive pathways is associated with various types of chronic pain through central sensitization and remodeling of brain connectivity. Within this context, extensive research has been conducted to evaluate the mechanisms and efficacy of certain non-pharmacological pain treatment modalities. These include neurostimulation, virtual reality, cognitive therapy and rehabilitation. Here, we summarize the involved mechanisms and review novel findings in relation to nociceptive desensitization and modulation of plasticity for the management of intractable chronic pain and prevention of acute-to-chronic pain transition.