Vibratory and thermal thresholds in diabetics with and without clinical neuropathy

Vibration and thermal detection threshold and heat pain threshold were determined in 34 diabetics scrutinized for clinical neuropathy using a standardized questionnaire and examination form. On the basis of the clinical grading patients were classified as having either no neuropathy or a neuropathy of increasing severity. As expected thermal and vibratory detection threshold increased with increasing severity of neuropathy. Comparison between diabetics without symptoms and signs of neuropathy and a corresponding non-diabetic control group showed that a warm sensibility index (WSI = the range in which non-noxious heat is perceived) was significantly lower on feet in diabetics than in their matched non-diabetic controls. The findings show that quantitative assessment of thermal sensitivity may be of value to detect early small nerve fiber dysfunction even in patients without symptoms or signs of a clinical neuropathy.