Brainwaves and EEG examples

The lowest frequencies are Delta. These are less than 4 Hz and occur in deep sleep and in some abnormal processes

Theta activity has a frequency of 4 to 8 Hz and is classed as “slow” activity.

Alpha waves are those between 8 and 12 Hz. Alpha waves will peak around 10 Hz. Good healthy alpha production promotes mental resourcefulness.

Beta activity is fast activity. It has a frequency of 13 and greater Hz. It reflects desynchronised active brain tissue. It is usually seen on both sides in symmetrical distribution and is most evident frontally

Click on the trace below to view a 10/20 qEEG trace showing Alpha, Beta and Theta waves within the trace.