Breach Rhythm Beyond Skull Defects: Clinical and Functional Insights from a Bilateral Lesion Case

Area of Science:

• Neurophysiology
• Clinical Electroencephalography (EEG)

Background:

• Breach rhythm (BR) is an EEG pattern over skull defects, often mistaken for epileptiform activity.
• Diagnostic uncertainty arises due to BR's resemblance to seizures, impacting patient management.

Purpose of the Study:

• To investigate the nature of breach rhythm (BR) in a patient with traumatic brain injury and skull defects.
• To determine if BR serves as a marker of cortical viability and function.

Main Methods:

• Case report of a 33-year-old male with bilateral skull defects and seizures.
• EEG analysis during interictal and ictal periods, observing BR characteristics.
• Correlation of BR presence/absence with cortical injury and seizure activity.

Main Results:

• Continuous BR observed over the right hemisphere, with slow waves on the left.
• Ictal discharges transiently modified BR morphology during focal seizures.
• Absence of BR over the left hemisphere despite a skull defect, suggesting severe cortical damage.

Conclusions:

• Breach rhythm (BR) is a dynamic indicator of cortical function, not just a passive artifact.
• BR modulation during seizures and its absence in damaged areas suggest it may be a marker of cortical viability.
• Recognizing BR patterns improves EEG interpretation in patients with brain lesions, preventing misdiagnosis of epilepsy.