P342 Diagnostic utility of MUNIX method in estimation of motor units loss in post-polio syndrome

Abstract

The aim of the study was to assess the value of the MUNIX method in terms of reflecting clinical dysfunction in patients with post-polio syndrome and to estimate the relationships between the grade of loss of motor units in post polio syndrome (PPS), and motor unit potential’s parameters and stage of muscle weakness regarding the stability or newness of weakness. Patients and methods The study group consisted of 12 patients with PPS at the mean age of 63 ±8 years, including 6 males (50%). All patients fulfilled the criteria for PPS according to Marches of Dime. Patients with neurological abnormalities such as the history of neuropathy, advanced discopathy, upper extremity injury were excluded. The duration of the new symptoms (PPS) was 6.5 yrs (2–20). Overall, we studied 132 muscles (MUNIX) and 96 muscles (EMG), divided into three groups: with normal strength (57), with stable weakness and atrophy (39), and with new weakness and atrophy (35). We performed MUNIX measurements in the abductor pollicis brevis (APB), abductor digiti minimi (ADM), biceps brachii (BB), tibial anterior (TA), extensor digitorum brevis (EDB), and abductor hallucis (AH) muscles and electromyography with MUAPs registration was done in BB, FID, VL,TA on both sides. Expanded Medical Research Council Scale for Manual Muscle Testing (MRC) was performed in each investigated muscle. Muscle strength according with Medical Research Council (MRC) was assessed. Results The MUNIX value correlated with the MRC score for each of the following muscle ABP, ADM, BB, TA, EDB, AH ( P 0.05 ) in contrary to MUPs parameters. MUNIX value in muscles with normal strength was significantly increased comparing with those with stable weakness and with new weakness. Conclusion Our study confirms that the MUNIX method is a sensitive tool reflecting motor dysfunction and could be a good biomarker for loss of motor neurons in PPS.