Cone waves are isolated slow waves that occur over the occiput with a triangular waveform. They are usually monophasic and less often diphasic, have a duration that is typically more than 250 milliseconds, and have a medium to high amplitude. Because of their amplitude and contour, they may be mistaken for sharp waves, but they are slow waves because of their duration. The occurrence of cone waves is both age and state dependent. They are present only from infancy through mid childhood, and only during non–rapid eye movement (NREM) sleep (Cervone and Blum, 2007; Fisch, 1999). They are most likely to occur between the ages of 6 months and 3 years (Dan, 2006).