There is much confusion about the American Spinal Injury Association Classification of spinal cord injury, also called the ASIA Impairment Scale. Here is the definition again:
Please note that the following is my interpretation of the ASIA Classification.A = Complete: No motor or sensory function is preserved in the sacral segments S4-S5.
B = Incomplete: Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5.
C = Incomplete: Motor function is preserved below the neurological level, and more than half of key muscles below the neurological level have a muscle grade less than 3.
D = Incomplete: Motor function is preserved below the neurological level, and at least half of key muscles below the neurological level have a muscle grade of 3 or more.
E = Normal: motor and sensory function are normal.
The definition is a little confusing because it is also a definition by omission. An ASIA A classification is the simplest. It simply means no motor *or* sensory in sacral S4-S5. If a person has rectal/anal sensation, that person is not an A. If the person has voluntary sphincter contraction, that person is not an A.
An ASIA B is relatively rare in that it is a person who has anal sensation but *no* motor function below the *neurological level*. This is a little tricky. The neurological level is not the *injury level*. The neurological level is the lowest segment that has normal motor and sensory function. So, for example, even if you had a C4 injury and started with a C4 neurological level and then recovered back C5 and C6, your neurological level is C6. Therefore, to be called an ASIA B, you must have some sensory function below C6. So, to be an ASIA B, you must have anal sensation. You don't need anything else but you must not have any motor function below the neurological level or else you would be an ASIA C.
A person is ASIA C if the person has at least sacral sensation and any motor function below the neurological level but less than half of the key muscles below the neurological level have a muscle grade of 3 or greater. By the way, if you have voluntary sphincter contraction, you are no longer ASIA B because the definition of ASIA B says no motor function preserved below the neurological level and voluntary sphincter contraction would represent motor function below the neurological level. If you are not an ASIA A and have any motor function below your neurological level, you would be at least ASIA C.
You would be an ASIA D if 50% or more of the key muscles below your neurological level have grades of 3 or more.
[This message was edited by Wise Young on 10-08-03 at 12:08 PM.]