EMG evaluation of the floppy infant: differential diagnosis and technical aspects.

Electromyographic examination of the newborn and young infant provides a relatively uncommon challenge to most electromyographers. The usual reason for referral for electromyographic studies in the newborn and young infant is to evaluate a floppy baby. The electromyographer must not only be aware of important differences in normal physiologic parameters but must also be familiar with a spectrum of diseases that are not typically encountered in the adult. The results of electromyography must also be correlated with the normal maturation of neuromuscular function. Although the most common pathophysiologic mechanisms affecting the peripheral motor unit are infantile motor neuron disease and the congenital myopathies, a large number of other disease entities warrant careful consideration.