The effect of biofeedback training on temperature control in reflex sympathetic dystrophy patients with sympathectomy

The most commonly prescribed treatments for reflex sympathetic dystrophy are aimed at blocking the effects of sympathetic hyperactivity. However, because the mechanisms that underlie its symptoms are difficult to explain there is a risk that some of the treatments that are directed at the sympathetic nervous system might do more harm than good. Therefore, the purpose of this study was to investigate temperature regulation through a programme of biofeedback-assisted relaxation techniques in a small group of patients who had undergone sympathectomies but little pain relief. Four subjects with diagnosed chronic reflex sympathetic dystrophy had baseline thermographic recordings taken before a 14-week training programme in relaxation techniques. Follow-up thermograms were obtained immediately following the training programme and again 3 months after training had been completed to assess the long-term effects of training. Biofeedback training had no detectable effect on temperature control between one side of the body and the other but did within regional areas of the same side. Three of the four patients were cooler on the sympathectomized side and with training two of the four achieved symmetry between the sides by cooling the unaffected side. Since the sympathectomized side would be expected to be warmer, these findings raise questions about the relationship between skin temperature and activity in sympathetic neurones and the temperature abnormality of the reflex sympathetic dystrophy syndrome.