Positive sharp waves and fibrillation potentials in polio survivors with sequelae: Are they due to late deterioration or radiculopathy?

Background & Objective: Needle electromyography (EMG) abnormalities can be observed in clinically affected or unaffected muscles in polio survivors. The primary aim of this study is to evaluate the positive sharp waves (PSWs) and fibrillation potentials (FPs) that can be observed in polio survivors. In addition, the presence of post-polio syndrome and radiculopathy was investigated in patients with PSWs/FPs.
Methods: Clinical features and needle EMG findings of polio survivors with sequelae who applied to our neurophysiology laboratory between August 2018 and January 2021 were analyzed retrospectively. Cervical and lumbosacral magnetic resonance imaging (MRI) of polio survivors with PSWs/FPs were included in the analyses. In addition, polio survivors were divided into groups with and without post-polio syndrome.
Results: Fifty-one polio survivors (33 male, 18 female) were included in the study. The mean age of the patients was 49.5±7.5 years. There were 13 (25.5%) polio survivors with post-polio syndrome. Needle EMG findings of 590 muscles were analyzed. PSWs/ FPs were found in 11 medial gastrocnemius, four iliopsoas, four tibialis anterior, two vastus lateralis muscles, and one deltoid muscle. PSWs or FPs were present in 12 (23.5%) of patients. PSWs/FPs were present in three (23.1%) and nine (23.7%) polio survivors with and without post-polio syndrome, respectively (p>0.05). Of the 12 patients with PSWs/FPs, 11 had cervical and lumbosacral MRIs. In eight (72.7%) of these 11 patients with PSWs/FPs, the nerve segment of the muscle with PSWs/FPs and the segment of radiculopathy detected by MRI were compatible with each other.
Conclusions: This study indicated that PSWs/FPs may be present in polio survivors. PSWs/FPs may be due to radiculopathy and/or late deterioration. It was concluded that PSWs/FPs are not a parameter that can be used to differentiate polio survivors with and without post-polio syndrome.