The Abbreviated Injury Scale (AIS), is another tool used in the assessment of brain injury severity. In contrast to the GCS, the AIS is an anatomical scoring system which ranks each anatomic region on a 1-6 ordinal scale (from minor to maximal) using neuroradiological or operative findings.

The AIS was first published in 1971 and has been continuously improved since its inception.  It was updated in 2005 and 2008.  It is usually used in conjunction with the Injury Severity Score which assesses patients involved in traffic accidents.

Injury SeverityAbbreviated Injury Score
minor injury1
moderate injury2
severe but not life-threatening3
potentially life-threatening but survival likely4
critical with uncertain survival5
unsurvivable injury (maximal possible)6
severity unknown9

Injuries are assigned to 5 body regions: General, Head and Neck, Chest, Abdomen, and Extremities and Pelvis.  For TBI, the Head and Neck Category is used.  Each type of injury is then rated from 1-6.

Head and Neck

cerebral injury with headache or dizziness but no loss of consciousnesshead and neck1
whiplash complaint with no anatomical or radiological evidencehead and neck1
abrasions and contusions of ocular apparatus (lids, conjunctivae, cornea, uveal injuries)head and neck1
vitreous or retinal hemorrhageshead and neck1
fractures and/or dislocation of teethhead and neck1
cerebral injury with/without skull fracture, less than 15 minutes unconsciousness, no post-traumatic amnesiahead and neck2
undisplaced skull or facial bone fractures or compound fracture of nosehead and neck2
laceration of the eye and appendageshead and neck2
retinal detachmenthead and neck2
disfiguring lacerationshead and neck2
whiplash severe complaints with anatomical and radiologic evidencehead and neck2
cerebral injury with or without skull fracture, with unconsciousness more than 15 minutes, without severe neurological signs, brief post-traumatic amnesia (less than 3 hours)head and neck3
displaced closed skull fracture without unconsciousness or other signs of intracranial injuryhead and neck3
loss of eyehead and neck3
avulsion of optic nervehead and neck3
displaced facial bone fractures or those with antral or orbital involvementhead and neck3
cervical spine fractures without cord damagehead and neck3
cerebral injury with or without skull fracture with unconsciousness of more than 15 minutes, with definite abnormal neurological signs; post-traumatic amnesia 3-12 hourshead and neck4
compound skull fracturehead and neck4
cerebral injury with or without skull fracture with unconsciousness of more than 24 hours; post-traumatic amnesia more than 12 hourshead and neck5
intracranial hemorrhagehead and neck5
signs of increased intra-cranial pressure (decreasing state of consciousness, bradycardia under 60, progressive rise in blood pressure, or progressive pupil inequality)head and neck5
cervical spine injury with quadraplegiahead and neck5
major airway obstructionhead and neck

The scores for TBI are totaled from the above.  The mortality or death rate is then calculated using the totaled scores.

Scoremortality rate if age ≤ 49mortality rate if age 50-69mortality rate if age ≥ 70
data extrapolated from Figure 4, Baker et al (1974)