Evaluation


Assessment using PainVision

Principle and Definition

PainVision is a device that compares the level of pain to the level of stimulating current (stimulation by pulse current). Pain is quantitatively assessed by measuring the stimulating current that is acknowledged by the patient as being equivalent in sensation to pain. Before evaluating pain, the baseline (Current Perception Threshold) is measured to eliminate individual variability due to various factors.

The pain level is a non-dimensional parameter at zero when no pain is felt, presenting the level of genuine pain in the rage of 2000+.

How to Take Measurements

PainVision takes measurements using electrical stimulation with a low-frequency current (50 Hz, 0 – 256 μA). A stimulating electrode needs to be placed on the inner side of the forearm, avoiding areas of pain. Current Perception Threshold and Pain Equivalent Current are measured three times by gradually increasing the stimulating current. The results will be recorded in the Software, and the pain level will be calculated.

How to Use

By measuring the degree of pain, PainVision allows quantitative assessment of the intensity of pain and the effect of treatment.

Conventional Pain Rating Methods

Since pain is essentially a patient’s subjective sense, assessment of pain is complicated by bias and psychological factors. Therefore, conducting an objective assessment of pain is associated with many difficulties. The followings are the methods that have been used traditionally. Combination of these methods with assessment using PainVision enables multifaceted assessment of pain:

Pain rating scales

  • Visual Analog Scale : VAS
  • Numerical Rating Scale : NRS
  • Verbal Rating Scale : VRS
  • Face Rating Scale : FRS

Pain rating scales including behavioral aspect

  • Prince Henry Pain Scale : PRS
  • Children’s Hospital Estarn Ontario Pain Scale : CHEOPS

Assessment of pain quality, behavior and QOL

  • McGill Pain Questionnaire : MPQ
  • SF-36 (Medical Outcome Study Short-Form 36-Item Health Survery)
  • PDAS (Pain Disability Assessment Scale)

Although it is difficult to quantify pain, it is possible to quantify the level or degree of pain.
(The information may be used for treatment or research)
Reference: Japan Medical Association Journal) 2009; 138(3): 572-573