Quantitative Evaluation of Pain during Electrocutaneous Stimulation using a Log-Linearized Peripheral Arterial...

Area of Science:

• Biomedical Engineering
• Neuroscience
• Pain Research

Background:

• Current subjective pain scales (e.g., visual analogue scale, numeric rating scale) have limitations in detecting inaccurate reports and are unsuitable for anesthetized or cognitively impaired patients.
• Peripheral sympathetic nerve activity is a physiological response to pain, offering a potential objective measure.

Purpose of the Study:

• To propose and validate a novel method for evaluating pain sensation (intensity, sharpness, dullness) using the arterial stiffness index.
• To establish a reliable, objective pain assessment tool applicable across diverse patient populations.

Main Methods:

• Collected electrocardiogram, blood pressure, and photoplethysmograms.
• Applied an arterial viscoelastic model to estimate arterial stiffness.
• Examined and modeled relationships between arterial stiffness index, self-reported pain, and electrocutaneous stimuli.

Main Results:

• The arterial stiffness index demonstrated a strong correlation with subjective pain sensations.
• Sigmoid function modeling showed high determination coefficients (R² ≥ 0.88 for intensity, R² ≥ 0.89 for sharpness, R² ≥ 0.84 for dullness).
• The model was particularly effective when stimuli evoked dull pain.

Conclusions:

• The arterial stiffness index can reliably quantify pain intensity, sharpness, and dullness.
• This objective method provides a promising alternative to subjective pain evaluations, enhancing clinical applicability.
• Further research can explore its utility in specific clinical scenarios, including anesthesia and dementia care.