Change in Vibratory Perception Threshold after Continuous Vibratory Stimulation by TM-31A in Diabetic Patients

Vibratory perception threshold (VPT) in diabetic patients (NIDDM) with (n=13) or without neuropathy (n=12) and age matched control subjects (n=12) was measured at the right internal malleolus using a vibratory perception meter (TM-31A). After continuous vibratory stimulation at 150 μm amplitude for 5 min, VPT was again measured at 0, 2 and 5 min. VPT in the three groups was significantly increased after the stimulation. VPT was significantly higher in both groups of diabetic patients than in controls at 0, 2 and 5 min after the stimulation. Additionaly, the increment in VPT from before to after the stimulation (at 0 min) showed significantly positive correlations with FPG and HbA₁c level, suggesting that the change in VPT after the stimulation may be related with glycemic control in diabetic patients. The measurement of VPT after continuous vibratory stimulation with a TM-31A revealed abnormal peripheral nerve function in diabetic patients who had no clinical neuropathy.