[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. The study included: a) clinical assessment (history and neurological examination); b) measurement of VPT at right metatarsus, right pretibial area and right metacarpus; c) electromiographical study (right peroneal, posterior tibial, right sural, right medial plantar); d) assessment of the autonomous nervous system (sympathetic and parasympathetic indexes); e) metabolic assessment (HbA1c at study and mean HbA1c in the previous 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 metatarsal region (p < 0.05) and tibia (p < 0.05) was observed. Clinical symptoms and changes at examination correlated with VPT at metatarsus (p < 0.05) and tibia (p < 0.05). No relationship was observed between VPT and metabolic control. In conclusion, vibration threshold increases with evolution time in diabetes, but it was not influenced by metabolic control. Its measurement by a simple method, such as biothesiometer, could be useful in diagnosing peripheral neuropathy in clinically asymptomatic patients.