The Thermocross: a simple tool for rapid assessment of thermal sensation thresholds

Abstract

We have developed the Thermocross, a simple device for rapid assessment of thermal sensitivity, tested it on healthy subjects and diabetic patients and evaluated its use in identifying patients whose sensation loss may expose them to the risk of neuropathic foot injury. Thermal discrimination deteriorated with age (P less than 0.001) in healthy subjects, but all the controls could detect a temperature difference less than or equal to 10 degrees C. In diabetic patients, the deficit in thermal sensation detected by the Thermocross paralleled the decline of nerve conduction. Thermocross thermal sensation was impaired in 87% of 38 ulcerated feet of 26 diabetic patients. We conclude that the Thermocross is a suitable tool for screening for sensation loss and that diabetic patients with impaired thermal sensation are vulnerable to ulceration. The Thermocross could also serve a useful educational purpose, the implications of reduced thermal sensation probably being more meaningful to patients and health care personnel than those of a reduction in the traditionally tested vibration sensation.