Physiotherapists need ways to measure the success of treatment. If pain is used as a measure, how much improvement is enough to say the treatment worked? In this study therapists used the standard numeric pain scale (NPS) with low back pain (LBP) patients to determine how much change was meaningful.

The NPS is used to measure pain by asking patients to rate their pain from zero (no pain) to 10 (worst pain). LBP patients at eight different clinics around the United States were included. Everyone rated their pain using the NPS before treatment was started. Other tools were used to measure function and disability.

Patients were put into one of two treatment groups. The first group received spinal manipulation and an exercise program. The second group just did lumbar stabilization exercises. Everyone was retested after one week of treatment and again after four weeks. The therapists also rated change in the patient since beginning treatment.

The results of this study show that a two-point change on the NPS is enough to be significant. It's not the result of some error in math. Therapists can use this scale to assess the results of treatment.

John D. Childs, PT, PhD, et al. Responsiveness of the Numeric Rating Scale in Patients with Low Back Pain. In Spine. June 1, 2005. Vol. 30. No. 11. Pp. 1331-1334.