In a recording of normal scalp EEG, alpha activity is the main posterior dominant background rhythm in adults and children older than 3 years. Abnormalities in the alpha rhythm include slowing, changes in amplitude, or absence of the posterior dominant background rhythm under varying conditions. In epilepsy, alpha abnormalities are recorded interictally and preictally. During intracranial EEG, bands of faster frequency are commonly recorded; these have been well characterized with or without an association with the epileptogenic zone. Alpha activity has not been previously described as an ictal pattern at seizure onset on scalp EEG in patients with epilepsy. At onset, mesial temporal onset seizures are strongly correlated with rhythmic theta activity, whereas neocortical (lateral) onset seizures have been associated with delta activity