What Is ASIA Score and How It Helps In Classification of Spinal Injury

ASIA socre is the score developed by the American Spinal Injury Association for essential minimal elements of neurologic assessment for all patients with a spinal injury. This is based on scores as assessed by examiner and is popularly called ASIA score.

These minimal elements are strength assessment of ten muscles on each side of the body and pin-prick discrimination assessment at 28 specific sensory locations on each side.

How To Calculate ASIA Score?

ASIA chart- Click to enlarge

Sensory Examination

The sensory levels are scored on a 0 to 2 scale for each dermatome. If body is divided into two identical halves there are 28 key sensory points to be tested. Each dermatome is tested forlight touch and pinprick sensations and labeld as NT (not testable) if cannot be tested.

Otherwisw, follwing scores are given to each sensory point

• 0 – The sensation is absent
• 1 – The sensation is present but imapired
• 2 – The sensation is normal

Scores ar4 eindividually tested for  both light touch and pin prick are normal.A maximum possibleis 112 points for each of them for a patient with normal sensation.

In addition presence or absence of anal sensation is noted.

Motor Examination

10 key muscles, 5 in the upper limb and 5 in the lower limb are etested.  Five specific upper extremity muscles, one from each respective segment of the cervical cord, are scored on a 5-point muscle grading scale.  Five specific lower extremity muscles are similarly scored.

Muscle strength is graded as

• 0   Total paralysis
• 1 -  Palpable or visible contraction
• 2 -  Active movement, full range of motion, gravity eliminated
• 3 -  Active movement, full range of motion, against gravity
• 4 -  Active movement, full range of motion, against gravity and provides some resistance
• 5 – Active movement, full range of motion, against gravity and provides normal resistance [Muscle able to exert, in examiner’s judgement, sufficient resistance to be considered normal if identifiable inhibiting factors were not present]
• NT – not testable. Patient unable to reliably exert effort or muscle unavailable for test-ing due to factors such as immobilization, pain on effort or contracture.

The sum of all 20 muscle yields a total motor score for each patient, with a maximum possible score of 100 points for patients with no weakness. A different score, however  for upper limbs and lower limbs can be calculated making it 50 maximum for both upper and lower limb.

Voluntary anal contraction is also noted.

Determine Single Neurological Level

After motor and sensory levels have been determined, the information is assimilated for determining a single neurological levels. This is important because the sensory and motor level may differ.

the neurological level is the lowest segment where motor and sensory function is normal on both sides, and is the most cephalad of the sensory and motor levels determined in sensory and motor examination.

Complete or incomplete spinal cord injury

Injury is complete if there is

• No voluntary anal contraction
• S4-5 sensory scores = 0
• no anal sensation = No

Otherwise injury is incomplete.

Grading of Impairment

The ASIA impairment scale describes a person’s functional impairment as a result of their spinal cord injury.

ASIA-Imapirment - Calculation

A- Complete

No motor or sensory function in the lowest sacral segment (S4-S5)

B- Incomplete

Sensory function below neurologic level and in S4-S5, no motor function below neurologic level

C- Incomplete

Motor function is preserved below neurologic level and more than half of the key muscle groups below neurologic level have a muscle grade less than 3.

D- Incomplete

Motor function is preserved below neurologic level and at least half of the key muscle groups below neurologic level have a muscle grade >3

E- Normal

Sensory and motor function is normal

ASIA elements have better reproducibility, they constitute a minimal data set desirable in all spinal injury patients for accurate communication across the personnel.It also makes follow up easy to assess.

Clinical evaluation and management, however, requires a neurologic assessment extending beyond the essential examination elements recommended by ASIA.  Assessment of lower extremity and perineal reflexes is critical to determine the severity of neurologic involvement. These elements are considered optional in the ASIA standards since they do not meet sufficient reproducibility criteria.

Categorization of a specific patient into a specific division of a classification requires some subjective judgment. The variability in these judgments makes comparisons difficult and  ASIA has defined these terms with specific criteria for clarity in current and future discussions. These specific definitions will improve categorization of spinal cord injury patients in scientific communication and allow more meaningful analyses.