PainVision PS-2100

PV was developed as a medical device that evaluates the strength of pain using a numerical value⁴⁶. The measurement principle of the system is to compare a unique electrical stimulation with the pain experienced by the patient^19,37. A painless electrical stimulation whose intensity is equivalent to the intensity of the pain experienced by the patient is applied, and the current value of this electrical stimulation is defined as “pain-compatible electrical current.” The patient’s threshold for the electrical stimulation is defined as the “current perception threshold” which is intended to eliminate inter-individual variability. With these two values, pain intensity is defined by the following equation:

An electrode is mounted on the inside surface of the forearm. An electrical current is made to flow (50 Hz; 0–150 µA RMS; pulse width: 0.3 ms), and the stimulation is strengthened^19,22. The patient is instructed to press a button the first time she/he perceives this stimulus; the current at this point is defined as the “minimum perceived current” value. As the stimulation current is increased, the patient is instructed to press the switch when they feel that the intensity of the stimulation current is equivalent to the intensity of the pain they are experiencing. The current is defined at this point as the “pain-equivalent current” value. Using the obtained values, “pain intensity” is calculated using the above formula. In the absence of pain, the value is 0 and increases according to the degree of pain. There is no upper limit. Each measurement is easily completed in a few minutes. PV was used to assess symptoms related to chronic CIPN subjectively before each cycle of chemotherapy.