Restless Legs Syndrome in Hemodialysis Patients: Clinical and Electrophysiological Study

Background: Hemodialysis-related restless legs syndrome (HD-RLS) is a common sensorial and motor disorder. The diagnosis of this disease is based on clinical criteria, and it has recently been proposed to use physiological parameters of the nerves related to the duration of the F wave as a supplementary diagnostic modality. The aim of the study is to determine the value of these parameters in the diagnosis of HD-RLS by comparing the differences between patients with HD-RLS and hemodialysis patients without RLS (HD-nRLS). Methods: A total of 20 HD-RLS patients, 33 HD-nRLS patients, and 30 age-and gender-matched healthy controls (HCs) were included in the study. The motor nerve conduction of the median and ulnar nerves in the upper limbs, as well as the tibial and peroneal nerves in the bilateral lower limbs, and the sensory nerve conduction of the sural nerve bilaterally and the superficial peroneal nerve, along with the F waves of the ulnar nerves, median nerve, and bilateral tibial nerve, were assessed. Results: Both groups of HD patients had variable levels of axonal degeneration and demyelination, with the HD-RLS patients having more severe lower limb involvement. The HD-RLS patients showed an extension of the F-wave duration (FWD) of the bilateral tibial, median, and ulnar nerves, along with an increased ratio between FWD and compound muscle action potential duration (CMAPD). Conclusion: Peripheral neuropathy occurs in patients with HD-RLS, and the FWD/CMAPD ratio could potentially serve as an adjunctive diagnostic tool for HD-RLS.