VARIABILITY IN FUNCTION MEASUREMENTS OF 3 SENSORY FOOT NERVES IN NEUROPATHIC DIABETIC-PATIENTS

We have examined the variability in function measurements of three sen sory foot nerves in neuropathic diabetic patients and have compared th em to measurements from healthy non-diabetic subjects. Sixty-six healt hy, non-diabetic subjects (30 (45%) males, mean age 56 years (range, 2 1-84 years)) and 61 age and sex matched diabetic patients (33 (54%) ma les, mean age 55 years (range, 34-78 years) Type 1 diabetes mellitus ( DM), mean duration of DM 24 years (range, 2-48 years)) were tested. Cu rrent perception threshold (CPT) at 250 Hz was employed to test the se nsory function of three nerves: superficial peroneal, sural and poster ior tibial, The vibration perception threshold, (VPT) and the cutaneou s perception threshold (CCPT) were also assessed at the great toe. Acc ording to the results of the neuropathy disability score (NDS), mild n europathy was present in 8 (13%) patients, moderate in 33 (54%) and se vere in 20 (33%), In both groups the CPT of the posterior tibial nerve was higher than the other two nerves (P < 0.0001) while no difference was found between the superficial peroneal and sural nerves (P = NS). CPT was different between the two feet at the superficial peroneal ne rve in 39 (64%) diabetic patients and 34 (52%) controls (P = NS), at t he sural nerve in 40 (65%) and 45 (68%) (P = NS), and at the posterior tibial in 36 (59%) and 33 (50%), respectively (P = NS). VPT was diffe rent by more than 10% at the great toes in 26 (43%) diabetic subjects and CCPT in 21 (34%). We conclude that although there is variation in sensory nerve function tests in diabetic patients this is similar to t hat noticed in healthy subjects, The great variability of all quantita tive sensory testing indicates that more than one site should be teste d.