Motor unit number estimation versus compound muscle action potential in the evaluation of motor unit loss in amyotrophic lateral sclerosis

Abstract Introduction Motor neuron loss is the primary pathologic feature of amyotrophic lateral sclerosis (ALS). An estimate number surviving motor units (MUs) represents a direct measure disease state in ALS. The objective study to compare MU estimation (MUNE) using multipoint stimulation method (MPS) and compound muscle action potentials (CMAP) amplitude patients with Methods Twenty-eight ALS duration 3–48 months were studied. Nerve conduction median, ulnar, tibial, common peroneal, sural nerves done. Besides, electromyography (EMG) cranio-bulbar, cervical, thoracic lumbosacral muscles, MPS-MUNE. Results MUNE decreased was positively correlated CMAP amplitude, medical research council (MRC) scale, functional rating scale (ALS-FRS). On contrary, negatively MUAP duration. Case detection by methods high as compared that amplitude. Conclusions highly specific more sensitive than detecting neurophysiologic abnormalities three times amplitudes. rate decline MPS-MUNE MRC score ALSFRS-R when expressed percentage change from baseline.