Neurological examination and eye examination are very useful to identify underlying problem in the brain.

The severity of coma impairment is categorized into several levels. Patients may or may not progress through these levels. In the first level, the brain responsiveness lessens, normal reflexes are lost, the patient no longer responds to pain and cannot hear.

Contrary to popular belief, a patient in a coma does not always lie still and quiet. They may move, talk, and perform other functions that may sometimes appear to be conscious acts but are not.^[1]

Two scales of measurement often used in TBI diagnosis to determine the level of coma are the Glasgow Coma Scale (GCS) and the Ranchos Los Amigos Scale(RLAS). The GCS is a simple 3 to 15-point scale (3 being the worst and 15 being that of a normal person) used by medical professionals to assess severity of neurologic trauma, and establish a prognosis. The RLAS is a more complex scale that has eight separate levels, and is often used in the first few weeks or months of coma while the patient is under closer observation, and when shifts between levels are more frequent.