breach rhythm
Abnormally fast activity recorded over skull defects, creating artifacts that must be distinguished from pathological findings.
Full Definition
Breach rhythm refers to abnormally high-frequency EEG activity (typically beta range) recorded over areas of skull defect, such as surgical craniotomy sites, fractures, or congenital defects. This phenomenon occurs because the absence of bone reduces electrical resistance, allowing higher frequencies to pass through more readily to scalp electrodes. The activity appears as excessive fast frequencies and increased amplitude over the affected region. While not pathological itself, breach rhythm can mask underlying abnormalities or be mistaken for seizure activity by inexperienced interpreters.
Usage
Usage note: Must not be confused with pathological fast activity or seizure patterns.
In Context
- "Prominent breach rhythm was noted over the left frontoparietal craniotomy site." — Post-surgical EEG report
- "The excessive beta activity represented breach rhythm rather than medication effect." — EEG interpretation notes