The Utility of a Novel Composite Parameter in Sensory Nerve Conduction Studies: Amplitude/Rise Time of Sensory Nerve Action Potential

Abstract

Objective: To evaluate the new composite parameter (i.e., the ratio of amplitude to rise time) of sensory nerve action potential in patients with diabetic distal symmetric sensory polyneuropathy (DSSP). Methods: 82 diabetic patients (two subgroups of normal and deteriorated NCS) and 34 controls were evaluated based on nerve conduction studies (NCS), rise time and the ratio of amplitude to rise time (A/RT). Results: The A/RT (cut off value = 1) of medial plantar, sural (SU) and superficial peroneal nerves were quite informative in each group (P < 0.0001, for relevant nerves). However, SU-A/RT was more reliable and useful than other nerves based on specifity and predictive values. Conclusions: Evaluation of SU-A/RT as an additional parameter would increase the diagnostic utility of NCS in detecting DSSP.