Bringing the feet in from the cold: thermal biofeedback training of foot-warming in Raynaud's syndrome.

The biofeedback-assisted treatment of a case of Raynaud's syndrome was examined in order to determine the relationship between learning of the hand-warming response and the subsequent ability to produce foot-warming responses. It was found that fluctuations in dermal hand and foot temperatures were not significantly related, either within or across treatment sessions. The obtained hand-warming response was of high magnitude and rapidly learned, while the foot-warming response was more modest and took substantially more trials to learn. These results indicate that an easy generalization of the hand-warming response cannot be assumed.