What effect can a skull breach have on an EEG recording?

A skull breach can significantly affect EEG recordings due to the changes in the electrical properties and impedance around the area of the breach. Specifically, an increase in excessive beta frequency activity can be observed. This is because a breach in the skull may lead to changes in the electromagnetic environment, which can promote abnormal beta waves that are indicative of increased cortical activity or arousal. The presence of excess beta activity can also reflect the potential influence on the brain's electrical landscape as a result of structural changes caused by the skull breach.

Other potential effects such as increased delta, heightened alpha, or reduced theta activity are less likely to correlate directly with the specific consequences of a skull breach. Delta activity typically indicates deep sleep or inactivity, alpha activity is associated with relaxed states, and theta activity is linked to light sleep or relaxed alertness. However, the immediate and more pronounced effect following a skull breach is the likelihood of excessive beta frequency due to the alterations in neural processing and sensitivity in the brain regions affected.