Extensor digitorum brevis in diabetic neuropathy: a controlled evaluation in diabetic patients aged 15-50 years

A reduction in the bulk of the extensor digitorum brevis muscle (EDB) may be a sign of diabetic neuropathy. We devised a semi-quantitative scale (normal, reduced or absent) for assessing the bulk of the EDB muscle, and judged it to be a sign of neuropathy in 375 of 395 diabetic patients aged 15-50 years in the county of Umeå, 79% of whom had Type 1 diabetes mellitus (DM), and in 100 healthy controls. Reduced or absent EDB was significantly more common in patients with Type 1 and Type 2 DM than in controls (44 and 48 vs. 12%; P less than 0.001). In patients with Type 1 DM, reduced or absent EDB was significantly correlated with age, longer duration of DM, smoking, dry feet, and foot ulcers, but not with fallen forefoot arch, hammer toes or callosities. Reduced or absent EDB was also associated with skin and nail lesions, including Melin's shin spots, purpura and yellow toenails, but not with necrobiosis. Sensory thresholds for vibration, perception and pain were all significantly elevated in Type 1 diabetic patients with impaired EDB, compared to Type 1 diabetics with normal EDB. In controls, impaired EDB was only significantly correlated with smoking. We conclude that the EDB test is easy to perform, and may be used to screen for neuropathy in Type 1 diabetic patients.