COMPARISON OF ELECTROPHYSIOLOGIC AND AUTONOMIC TESTS IN SENSORY DIABETIC NEUROPATHY

We examined autonomic function in 46 patients with symmetric sensory n on-insulin dependent diabetic neuropathy without autonomic symptoms an d 31 age-matched control patients using the composite autonomic scorin g scale (CASS) and electrophysiologic examination. The patients were d ivided into three groups by subjective severity of pain or numbness; 1 7 had slight pain or numbness, 15 had mild pain or numbness, and 14 ha d moderate pain or numbness. The patients in the moderate group had th e following: a mild reduction in systolic and mean blood pressure (BP) within 1 minute of head-up tilt and a partial recovery after 5 minute s; an excessive fall in early phase II (IIe), an absence of late phase II (III) and reduced phase TV beat-to-beat BP responses to Valsalva m aneuver (VM); a poor heart rate response to deep breathing; a reduced quantitative sudomotor axon reflex test (QSART) response in distal leg and foot; the highest CASS among the 3 groups; and reduced conduction velocity and amplitude in post-tibial nerve and sural nerve. The mild group had a mild reduction in BP during phase IIe and an absent phase III but normal phase TV overshoot during VM; a reduced QSART in the f oot; a CASS between the moderate and slight groups; and reduced conduc tion velocity and amplitude in post-tibial nerve and reduced amplitude in sural nerve. The slight pain group had no abnormalities except for mild cardiovagal dysfunction. CASS gathered from all cases had a sign ificant correlation with amplitude of sural nerve. These results sugge st that the patients with symmetric sensory diabetic neuropathy may al so have autonomic dysfunction, although they did not have any obvious autonomic symptoms, and that abnormalities in autonomic function paral lel changes in somatic function in peripheral nerve. The CASS may be a sensitive tool, similar to the neurophysiologic test, for assessing d iabetic neuropathy.