What is the definition of mild moderate and severe brain injury?

Mild brain injury, often referred to as a concussion, typically involves a temporary disruption of brain function, with symptoms such as confusion or brief loss of consciousness lasting less than 30 minutes. Moderate brain injury may involve a longer loss of consciousness (up to 24 hours) and more pronounced cognitive impairments, often leading to lasting changes in behavior or functioning. Severe brain injury results in extended unconsciousness or coma, significant physical and cognitive disabilities, and may require extensive rehabilitation. The classification is primarily based on the severity of symptoms and the duration of unconsciousness.