Abstract
[Purpose] The purpose of this study was to investigate the differences of sensory nerve fiber degeneration rates with duration of diabetes mellitus, as well as the difference in the degeneration rate of nerve fibers by selectively providing stimulation to the A-beta, A-delta, C fibers and measuring the current perception threshold (CPT) of diabetic patients. [Subjects] The subjects of this study were diabetic patients complaining of significant neuropathy symptoms such as numbness, dullness and paraesthesia. [Methods] Stimulations of 5 Hz, 250 Hz, and 2,000 Hz of frequency were generated with a Neurometer CPT (Neurotron Inc., Baltimore, MD, U.S.A.) and delivered selectively to C fibers, A-delta fibers and A-beta fibers. The intensity of the stimulation of 5 Hz, 250 Hz and 2,000 Hz increased to 0.01 mA. The independent t-test was used to compare perception thresholds. [Results] In the case of the right lower limb, the threshold value of A-beta fibers varied with the duration of diabetes and was particularly higher in the group of patients with 10 years or longer duration. The threshold value of A-delta fibers also varied with diabetes duration. That of the group with diabetes duration from 5 years to less than 10 years was not significantly different from that group with diabetes of the duration of 10 years or longer. However, the threshold value of the group with diabetes duration of 10 years or longer was higher than that of the groups of other durations. [Conclusion] The perception thresholds varied with diabetes duration and showed that degeneration of A-beta fibers and A-delta fibers that have myelin was more rapid than that of C fibers that are without myelin. Therefore, therapeutic interventions should be applied at the early stage of neuropathy.
