A modified visual analogue scale for the assessment of chronic pain.

The present common evaluation of pain is scored through the use of visual analogue scale (VAS) to assess the intensity of pain and, sometimes, an additional table in which the frequency of pain attacks during the day is reported. We propose a modified 2D-VAS to assess both the intensity and the frequency (expressed by the percentage of the time in which pain is experienced during the day). Thus with only one scale and graphic representation, we can have a clear picture of the patient's condition before and during any treatment to relieve his pain.