Asymmetry: referential versus bipolar montage

A previous post refers.

Asymmetries may be missed by looking at common average montages

This is a more striking example:

The above page, represented on bipolar montage:

While there is an asymmetry of beta frequencies on the common average montage, especially over the central-parietal regions, the asymmetry is easily missed. The bipolar montage demonstrates suppression of normal rhythms over the left hemisphere; the suppression over the left hemisphere cannot be appreciated on the referential montage. The EEG has been performed on a patient who has previously had a left hemispherectomy.

Here is another example: