Comparison of diagnostic value of nerve conduction studies and F-wave in patients with diabetic polyneuropathy: a retrospective cross-sectional study

Background: Diagnosis of polyneuropathy is typically made using sensory and motor nerve conduction studies (NCS). These tests include measurement of amplitude, velocity, and delay of sensory and motor waves. These waves cannot assess the entire length of the nerve, proximal parts in special. F-wave is the only test capable of measuring the entire length of the nerve. The purpose of this study was to evaluate the value of F-wave in patients with diabetic polyneuropathy.

Methods: This is a retrospective study assessing the value of nerve conduction studies and F-wave in the diagnosis of 148 patients with diabetic polyneuropathy referred to hospitals under the supervision of the University of Iowa from October 1, 2016, to September 5, 2018. Motor neurons of median, ulnar, peroneal, and tibial nerves and sensory neurons of median, ulnar, and sural nerves were assessed using two techniques of NCS and F-wave. Then the data were compared.

Results: The results of this study showed that F-wave in all of the evaluated nerves (median, ulnar, tibial and peroneal) detected abnormalities to more extents than routine NCS (P <0.001). When total neuronal abnormalities were accumulated, this value was 82٪ for NCS, while 99٪ for the F wave (P < 0.001).

Conclusion: Findings of the current study showed that the assessment of delayed nerve conducting through F-waves can diagnose diabetic polyneuropathy to better extents as compared to NCS. Further evaluations are recommended.