The American Spinal Injury Association Impairment Scale is a standardized neurological examination used by the rehabilitation team to assess the sensory and motor levels which were affected by the spinal cord injury. The scale has five classification levels, ranging from complete loss of neural function in the affected area to completely normal. The results help the team set functional goals based on the neurological level of injury that is determined. Elements of the scale, according to the National Institutes of Health, include:
Grade A: The impairment is complete. There is no motor or sensory function left below the level of injury.
Grade B: The impairment is incomplete. Sensory function, but not motor function, is preserved below the neurologic level (the first normal level above the level of injury) and some sensation is preserved in the sacral segments S4 and S5.
Grade C: The impairment is incomplete. Motor function is preserved below the neurologic level, but more than half of the key muscles below the neurologic level have a muscle grade less than 3 (i.e., they are not strong enough to move against gravity).
Grade D: The impairment is incomplete. Motor function is preserved below the neurologic level, and at least half of the key muscles below the neurologic level have a muscle grade of 3 or more (i.e., the joints can be moved against gravity).
Grade E: The patient's functions are normal. All motor and sensory functions are unhindered.
Learn more about how a spinal cord injury is diagnosed here.