The use of EEG in non-clinical research is a growing field, particularly as it has relatively low running costs, is now non-invasive and is tolerated well by most people. EEG detects changes in the brain very quickly (microsecond changes can be detected) and the data can be used relatively easily to produce meaningful brain activity maps suitable for most purposes.
The brainwaves we are most interested in are the Delta, Theta, Alpha and Beta waves. Brainwaves are measured in Hertz – the number of cycles per second:
Delta (0.5-4Hz) – indicating deep sleep and restfulness
Theta (4-8Hz) – indicating deep meditative states, daydreaming and automatic tasks
Alpha (8-15Hz) – indicating relaxed alertness but restful and relaxing, not anxious
Beta (15-30Hz) – indicating wakefulness, alertness, mental engagement and conscious processing of information, can be associated with anxiety
The normal Electroencephalography (EEG) varies by age. The neonatal EEG is quite different from the adult EEG. The EEG in childhood generally has slower frequency oscillations than the adult EEG.
So what do these brainwaves look like?