- The ASIA (American Spinal Injury Association) Impairment Scale (AIS), based on the Frankel scale, is a clinician-administered scale used to classify the severity (completeness) of injury in individuals with SCI. It identifies sensory and motor levels indicative of the highest spinal level demonstrating “unimpaired” function. Preservation of function in the sacral segments (S4-S5) is a key for determining the AIS grade.
- 5 point ordinal scale, based on the Frankel scale, classifies individuals from A” (complete SCI) to “E” (normal sensory and motor function):
- A: Complete. No sensory or motor function is preserved in the sacral segments S4-S5.
- B: Sensory incomplete. Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5 (light touch, pin prick at S4-S5 or deep anal pressure), AND no motor function is preserved more than three levels below the motor level on either side of the body.
- C: Motor incomplete. Motor function is preserved below the neurological level and more than half of key muscle functions below the single neurological level of injury (NLI) have a muscle grade less than 3.
- D: Motor incomplete. Motor function is preserved below the neurological level and at least half of key muscle functions below the NLI have a muscle grade of 3 or greater.
- E: Normal. If sensation and motor function as tested with the ISNCSCI are graded as normal in all segments, and the patient had prior deficits, then the AIS grade is E. Someone without an initial SCI does not receive an AIS grade.
- AIS scores are considered essential when classifying persons with SCI as to their neurological status. AIS scores are routinely collected in administrative databases such the Model Systems and CIHI National Rehabilitation Reporting System.
- This is an internationally recognized standard that is widely used for research and clinical purposes. Its development and continued evolution are well grounded in expert clinical consensus thereby ensuring high content validity.
- The exam is generally well tolerated although sensory testing for those with severe hypersensitivity may be uncomfortable and testing for anal sensation/voluntary contraction can result in the stimulation of a bowel movement.
- The test may pose a significant clinician/patient burden unless the clinician is experienced and well-practiced in the test.
- Preservation of function in the sacral segments (S4-S5) is key for determining the AIS.
Body Function ▶ Neuromusculoskeletal & Movement-Related Functions and Structures.