Introduction. Distal symmetric polyneuropathy (DSP) is the most common form of diabetic neuropathy. Material and Methods. We have performed a study in adult patients with diabetes mellitus (DM) type 1, where the disease duration < 5 yrs and the age of patients < 40 yrs were inclusion criteria. Totally 61 patients (31 women and 30 men) with an average age of 25 ± 5.7 yrs were studied. Median duration of the disease was 12 (3, 24) months. Nerve conduction velocity (NCV), distal latency and amplitude of sensory nerve action potential (SNAP) of sensitive nerves (plantar medial – PM, and sural nerves) were evaluated by electromyography (EMG). The presence of risk factors of DSP (age, body height, serum lipid levels and hypertension) as well as an indicator of metabolic compensation – HbA1c were assessed. Results. There were found decreased NCV 32.6 ± 7.6 m.s-1 (P<0.001) and prolonged latency 5.3 ± 1.3 ms (P<0.05) in the PM nerve, reduced SNAP in sural nerve 11 (7, 17) µV (P<0.05). Only poor correlations were revealed between EMG findings, somatometric parameters, duration and compensation of DM, and serum lipid levels. Electrophysiological parameters in the PM nerve were changed and thus fulfilled criteria for subclinic stage of DSP in 34 patients (55.7 %). Out of these, 30 patients (88.2 %) had decreased NCV of the PM nerve of 27.4 ± 5.1 m.s-1. Pathological EMG findings (i.e. prolonged distal latency and/or reduced SNAP and/or decreased NCV) in the PM nerve correlated neither with age, duration and compensation of DM, nor with serum lipid levels. Conclusion. The PM nerve seems to be the first affected in the course of DSP as assessed by EMG studies.

        Key words: diabetic polyneuropathy, electromyography, nerve conduction velocity