Delta wave activity occurs most frequently during stage 4 non-rapid eye movement sleep accounting for 50% or more of the EEG record during this stage.[2]
Analysis of the waking EEG of a newborninfant indicates that delta wave activity is predominant. In the case of a 5yr old child large amounts of delta wave activity still appear in a waking EEG.[3]
Delta wave activity during Slow-wave sleep declines during adolescence. A decline of 25% between the ages of 11yrs and 14yrs has been reported.[4]
Disorders
Large amounts of delta wave activity are not common in healthy adults during the waking state. However multiple studies have indicated the presence of increased delta activity in adults during states of intoxication or delirium and those diagnosed with dementia or schizophrenia[5]
^ Hales, Robert E.; Yudofsky, Stuart C. (2007). The American Psychiatric Publishing Textbook of Neuropsychiatry and Behavioral Neurosciences, Fifth Edition (American Psychiatric Press Textbook of Neuropsychiatry). American Psychiatric Publishing, Inc. ISBN 1-58562-239-7.
