Comparison of fixed interval and visual analogue scales for rating chronic pain.

A visual analogue scale (VAS) and a 4-point scale (FPS) have been compared in patients suffering from prolonged constant pain due to chronic inflammatory or degenerative arthropathy. Each patient was treated with a constant low or high dose of paracetamol or dihydrocodeine throughout a four week period. The VAS was accurate, as reliable and more sensitive than the FPS in registering the intensity of chronic pain.