What can be an indicator of a skull defect during an EEG?

A breach rhythm refers to an abnormal pattern observed in an electroencephalogram (EEG) that can indicate a defect in the skull. This pattern typically appears when there is a breach in the integrity of the skull, such as a surgical incision or trauma, which may expose the cerebral cortex to the electrical activity of the underlying brain. The presence of a breach rhythm is characterized by certain EEG features, such as increased amplitude and irregular wave patterns, which can be detected over the region of the skull defect.

In contrast, cerebral hemorrhage, constriction of blood vessels, and hypoxia may produce various other changes in the EEG but do not specifically indicate a skull defect. These conditions can affect brain function and blood flow, resulting in different types of changes such as slowing of brain waves or the presence of abnormal waves, but they do not reflect the local effects associated with a breach in the skull itself. Therefore, the presence of a breach rhythm serves as a more definitive indicator of skull abnormalities during an EEG examination.