Otoacoustic emissions (OAE) are sounds that are produced by healthy ears in response to acoustic stimulation or occurs spontaneously. They are considered to be epiphenomena and by-products of the activity of the outer hair cells in the cochlea. Otoacoustic emissions were first reported by Kemp in 1978. Although his observations were greeted with skepticism, OAEs have since been reliably confirmed. They appear to be generated by motile elements in the cochlear outer hair cells. Otoacoustic emissions are widely used for newborn hearing screening and for identifying the site of lesion in hearing disorders.