Brain Death: Definition, Diagnosis & Legal Status

Definition

Brain death = irreversible cessation of all brain functions, including brainstem. No potential for consciousness or cognitive function remains.

Legally recognized as death in most jurisdictions, even if heartbeat/circulation are mechanically maintained.

Diagnostic Criteria

• Absent brainstem reflexes (corneal, pupillary, gag, cough).
• No spontaneous respiration (apnea test).
• Confirmatory tests (optional): EEG, cerebral blood flow study, CT/MRI showing catastrophic injury.

Brain Death vs. Coma

• Coma – deep unconsciousness with preserved brain activity; potential recovery.
• Brain death – complete, irreversible loss of all brain function; biological impossibility of recovery.