12y

Background rhythms vary quite a lot from one person to the next.

If you count carefully, you will find 13 Hz rhythms primarily over the occipital regions of the above patient. These are reactive (appear prominently after eye closure (4s). At times they are maximal in amplitude on the left (in the middle of the page) and on other occasions on the right (last 1-2s).

Alpha rhythms vary markedly in frequency from one person to the next. This is at the upper end of the alpha spectrum.