When recorded from over or near a burr hole, the EEG may show?

When recording an EEG over or near a burr hole, it is often the case that you will observe higher amplitude activity over the affected area. This can be attributed to several factors, including the loss of normal cerebral tissue and the potential alteration of the electrical properties of the cortex beneath the burr hole.

When the skull is drilled, it can create a change in the impedance and may also lead to direct exposure of brain tissue. As a result, electrical signals from the underlying brain might become more prominent, reflected as higher amplitude in the recorded EEG patterns.

This observation is critical in EEG interpretation, as it may assist in identifying focal abnormalities, cerebral lesions, or areas undergoing pathophysiological changes. In contrast, the other options such as lower amplitude activity, no asymmetries, or slower frequencies generally do not align with the expected physiological changes that occur due to the presence of a burr hole. Higher amplitude activity specifically signals increased electrical activity that may be associated with underlying neural processes.