Learning processes in the persistence behavior of chronic low back pain patients with repeated acute pain stimulation.

Twenty-one chronic low back pain (CLBP) patients and 20 control subjects participated in 8 successive cold pressor tests (CPT). The hypotheses were that: (1) CLBP patients would demonstrate poorer acute pain tolerance and report higher acute pain, and (2) CLBP patients would become sensitized during 8 successive CPT trials, while control subjects would habituate, resulting in increasing differences in test behavior between both groups. The results show that the first hypothesis was confirmed. The second hypothesis requires modification, as the control group both habituated and became sensitized, while within the CLBP group no learning or training effect was found. These findings lead one to conclude that the deviant acute pain behavior of CLBP patient may be regarded either as a consequence of CLBP or as an important risk factor in the development of CLBP. Patients with relatively high CLBP levels performed poorly on the CPT as compared with patients with relatively low CLBP levels.