Thermal biofeedback and periodic movements in sleep: patients' subjective reports and a case study.

Periodic movements in sleep (PMS) is a sleep disorder characterized by repetitive leg kicks accompanied by arousals. In our clinical experience, many patients with PMS anecdotally report that they suffer from cold feet. This study explored whether there is an increased incidence of cold feet complaints in patients with periodic movements in sleep. Results indicated that, indeed, significantly more patients with leg kicks complain of cold feet as compared to patients without leg kicks. A case study was then conducted to determine whether foot thermal biofeedback training would alleviate symptoms of periodic movements in sleep. The number of leg kicks decreased from a mean of 536 per night before biofeedback training to a mean of 19.5 after training. These data lend support to our hypothesis that poor circulation may be contributing to the severity of periodic movements in sleep and that thermal biofeedback may afford an alternative treatment strategy.