This article reviews research on the relatively recently discovered event-related potential component, the mismatch negativity (MMN), which is of great potential interest for understanding central auditory function and various forms of its pathology. This change-specific response can serve as an accurate objective measure for central sound representations that form the basis, for instance, for correct hearing of speech. Deficiencies in the MMN may be related to different forms of deficits in central auditory processing.