MEASUREMENT OF VIBRATORY THRESHOLD IN THE DIAGNOSIS OF DIABETIC NEUROPATHY

The usefulness of the quantitative measurement of vibration perception threshold (VPT) was assessed by a biothesiometer in the diagnosis of peripheral neuropathy in 36 patients with type I diabetes mellitus. Th e study included: a) clinical assessment (history and neurological exa mination); b) measurement of VPT at right metatarsus, right pretibial area and right metacarpus; c) electromiographical study (right peronea l, posterior tibial, right sural, right medial plantar); d) assessment of the autonomous nervous system (sympathetic and parasympathetic ind exes); e) metabolic assessment (HbA1c at study and mean HbA1c in the p revious year). The prevalence of peripheral neuropathy was 38%. VPT at metatarsal region in diabetic patients was higher than in controls (p <0.05) and a positive correlation with evolution time of disease at me tatarsal region (p<0.05) and tibia (p<0.05) was observed. Clinical sym ptoms and changes at examination correlated with VPT at. metatarsus (p <0.05) and tibia (p<0.05). No relatioship was observed between VPT and metabolic control. In conclusion, vibration threshold increases with evolution time in diabetes, but it was not influenced by metabolic con trol. Its measurement by a simple method, such as biothesiometer, coul d be useful in diagnosing peripheral neuropathy in clinically asymptom atic patients.