Abstract
This chapter examines the different methods of Motor unit number estimation (MUNE), their advantages and limitations. The concept of obtaining a motor unit number estimate is remarkably simple. A maximum compound motor action potential (CMAP) is recorded in response to supramaximal stimulation of the nerve innervating the muscle being recorded. A crucial assumption of the incremental method is that each response increment resulting from graded stimulation represents the addition of a single motor unit. The multiple point stimulation technique was developed to avoid the problem of alternation associated with the incremental technique. Brown and Milner-Brown in 1976 suggested stimulation at multiple locations along the nerve to obtain a more representative sample of motor units and more important to avoid the problem of alternation. An important assumption is that there is no bias in selection of motor units and that the sample is representative of the population of motor units.