Neurological function was determined in diabetic patients with peripheral vascular disease and foot ulcers (n = 13). This was compared to that of diabetic patients without foot ulcers with (n = 23) and without (n = 13) symptoms of neuropathy. Diabetic patients with typical neuropathic ulcers (n = 13) and age-matched healthy controls (n = 20) were also studied. The beat-to-beat variation with deep breathing was 6.1 ± 1.0 beats/min in those with peripheral vascular disease and foot ulcers, less than 50% of that of diabetic patients without foot ulcers (p < 0.01) or normal controls (p < 0.005). Autonomic surface potentials in the soles were greatly diminished or absent in nearly all the patients with peripheral vascular disease and ulcers. Quantitative sensory testing revealed profound abnormalities in small fiber (heat and cold sensation) and large fiber (vibration sensation) function in diabetic patients with peripheral vascular disease and foot ulcers. Our results document the presence of advanced autonomic and somatosensory neuropathy in nearly all diabetic patients with peripheral vascular disease and foot ulcers.

There has been recent interest in measuring sympathetic sudomotor function by autonomic surface potential analysis. The purpose of the present study was to assess factors affecting the reproducibility of the test. We determined the within‐day and between‐day reproducibility in 24 healthy vclunteers. We used an increasing rather than a constant electrical stimulus to minimize habituation. The amplitudes were still highly variable (an average within‐day coefficient of variation in the soles of 35%). Habituation did not, however, affect the latencies of the responses, which were much more reproducible (an average within‐day coefficient of variation in the soles of 8%). Studies of between‐day reproducibility revealed that the mean amplitudes were lower on day 2 vs. day 1 (0.706 ± 0.10 vs. 0.85 ± 0.10 mV in the soles, P < 0.01) but the mean latencies were similar on the different testing days (2.09 ±.04 seconds for the soles on day 1 vs. 2.16 ±.05 seconds on day 2). We also assessed the sensitivity of surface potential analysis and report the results of testing 35 patients with far advanced autonomic neuropathy. © 1992 John Wiley & Sons, Inc.