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Ano ang ASIA Impairment Scale (SCI)?
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The ASIA Impairment Scale (AIS) is the internationally accepted classification system for documenting the severity and level of spinal cord injury (SCI). It was developed by the American Spinal Injury Association and the International Spinal Cord Society and is formally known as the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). The scale classifies injury into five grades from A to E based on the completeness of motor and sensory impairment below the neurological level of injury. Grade A (complete) indicates no motor or sensory function is preserved in the sacral segments S4-S5. Grade B (sensory incomplete) indicates that sensory but not motor function is preserved below the neurological level and extends through sacral segments S4-S5. Grade C (motor incomplete) indicates motor function is preserved below the neurological level with more than half of the key muscle groups below the injury level having a muscle grade less than 3 (not active against gravity). Grade D (motor incomplete) indicates motor function is preserved below the neurological level with at least half of the key muscle groups having a muscle grade of 3 or more (active against gravity). Grade E (normal) indicates that all sensory and motor function tested is normal, though the patient may still have neurological findings. Determining the Neurological Level of Injury (NLI) requires testing of ten key muscle groups bilaterally (five per side, upper and lower limb) on a 0-5 scale and testing pinprick and light touch sensation in 28 dermatomes bilaterally. The NLI is defined as the most caudal spinal cord segment with normal motor AND sensory function on both sides.
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Pormula
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ASIA Impairment Scale: A=Complete (no sacral S4-S5 motor/sensory); B=Sensory incomplete (sensory preserved at S4-S5, no motor below NLI); C=Motor incomplete (motor preserved below NLI, >50% key muscles <grade 3); D=Motor incomplete (motor preserved below NLI, ≥50% key muscles ≥grade 3); E=Normal (all sensory/motor normal); NLI=most caudal segment with normal motor AND sensory bilaterallyPaliwanag ng variable
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| Simbolo | Pangalan | Yunit | Paglalarawan |
|---|---|---|---|
| AIS | ASIA Impairment Scale Grade | A-E | A=complete, B=sensory incomplete, C=motor incomplete <50% grade≥3, D=motor incomplete ≥50% grade≥3, E=normal |
| NLI | Neurological Level of Injury | spinal segment | Most caudal segment with normal motor AND sensory function bilaterally |
| TMS | Total Motor Score | 0-100 | Sum of 10 key muscle groups each side (0-5 scale); upper 0-50, lower 0-50 |
| TSS | Total Sensory Score | 0-224 | Light touch + pinprick across 28 dermatomes bilaterally (each 0-2) |
Paano ASIA Impairment Scale (SCI)
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- 1Test light touch and pinprick sensation in all 28 key dermatomes bilaterally (C2-S4/5), scoring each 0=absent, 1=impaired, 2=normal; determine the most caudal level with normal (2/2) sensation on both sides.
- 2Test motor strength in ten key muscle groups bilaterally on the 0-5 Medical Research Council scale: C5=elbow flexors, C6=wrist extensors, C7=elbow extensors, C8=finger flexors, T1=finger abductors, L2=hip flexors, L3=knee extensors, L4=ankle dorsiflexors, L5=long toe extensors, S1=ankle plantar flexors.
- 3Determine the motor level as the most caudal key muscle group graded ≥3/5 with the segment above graded 5/5; do this separately for left and right sides.
- 4Determine the neurological level of injury (NLI) as the most caudal level with normal sensory AND motor function bilaterally.
- 5Test sacral sparing: any sensation at S4-S5 dermatome, deep anal pressure sensation, or voluntary anal sphincter contraction — presence of any sacral sparing indicates incomplete injury.
- 6Calculate the Total Motor Score (upper limb 0-50, lower limb 0-50, total 0-100) and the Total Sensory Score (light touch 0-112, pinprick 0-112) for quantitative tracking.
- 7Assign AIS grade A-E based on sacral sparing (grade A = no sacral, B = sensory only, C/D = motor, E = normal) and proportion of key muscles ≥3 below NLI.
Mga Nalutas na Halimbawa
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Tetraplegic (quadriplegic) classification; intensive rehabilitation for preserved C5 function
C5 complete SCI means elbow flexion is preserved (deltoids, biceps) but wrist extension and below are absent. Patient requires power wheelchair and significant ADL assistance.
Sacral sparing confirms incomplete injury; better prognosis for functional recovery than AIS A
The presence of sacral sensation despite no motor function distinguishes AIS B from AIS A. AIS B carries a better prognosis for functional motor recovery than complete injury.
Good rehabilitation potential; most AIS D patients recover functional ambulation
AIS D is the most favourable motor incomplete classification. The majority of AIS D patients achieve community ambulation with appropriate rehabilitation.
Clinical recovery; must document initial injury classification for comparison
AIS E indicates full neurological recovery. The initial classification (e.g., AIS B at admission) should still be documented to characterise the degree of recovery.
Mga praktikal na gamit
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Classifying all acute SCI admissions to determine rehabilitation goals, care planning, and assistive device needs., representing an important application area for the Spinal Cord Injury in professional and analytical contexts where accurate spinal cord injury calculations directly support informed decision-making, strategic planning, and performance optimization
Enrolment and stratification in SCI clinical trials testing neuroprotective agents, stem cell therapies, or rehabilitation technologies., representing an important application area for the Spinal Cord Injury in professional and analytical contexts where accurate spinal cord injury calculations directly support informed decision-making, strategic planning, and performance optimization
Disability pension and compensation assessments requiring standardised documentation of neurological impairment level and severity., representing an important application area for the Spinal Cord Injury in professional and analytical contexts where accurate spinal cord injury calculations directly support informed decision-making, strategic planning, and performance optimization
Monitoring recovery trajectory in SCI rehabilitation units to identify patients progressing towards ambulation versus those requiring wheelchair optimisation., representing an important application area for the Spinal Cord Injury in professional and analytical contexts where accurate spinal cord injury calculations directly support informed decision-making, strategic planning, and performance optimization
Academic researchers and university faculty use the Spinal Cord Injury for empirical studies, thesis research, and peer-reviewed publications requiring rigorous quantitative spinal cord injury analysis across controlled experimental conditions and comparative studies
Mga espesyal na kaso
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Central Cord Syndrome
In the Spinal Cord Injury, this scenario requires additional caution when interpreting spinal cord injury results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when spinal cord injury calculations fall into non-standard territory.
Anterior Cord Syndrome
In the Spinal Cord Injury, this scenario requires additional caution when interpreting spinal cord injury results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when spinal cord injury calculations fall into non-standard territory.
Brown-Sequard Syndrome
In the Spinal Cord Injury, this scenario requires additional caution when interpreting spinal cord injury results. The standard formula may not fully account for all factors present in this edge case, and supplementary analysis or expert consultation may be warranted. Professional best practice involves documenting assumptions, running sensitivity analyses, and cross-referencing results with alternative methods when spinal cord injury calculations fall into non-standard territory.
Conus and Cauda Equina Injuries
{'title': 'Conus and Cauda Equina Injuries', 'body': 'Injuries at L1-L2 may involve the conus medullaris (lower motor neurone) causing areflexic bladder, bowel, and sexual dysfunction. Cauda equina injuries below L2 involve nerve roots only, with potential for better recovery. These are classified using ISNCSCI but managed differently from cord injuries.'}
ASIA Impairment Scale Grades
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| Grade | Classification | Definition | Prognosis |
|---|---|---|---|
| A | Complete | No motor/sensory at S4-S5 | Poorest; <5% motor recovery below NLI |
| B | Sensory incomplete | Sensory but not motor preserved at S4-S5 | ~50% convert to motor incomplete |
| C | Motor incomplete | Motor preserved, >50% key muscles <grade 3 | Variable; intensive rehab critical |
| D | Motor incomplete | Motor preserved, ≥50% key muscles ≥grade 3 | Good; most achieve ambulation |
| E | Normal | All sensory and motor function normal | Full neurological recovery |
Mga madalas itanong
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What is the difference between AIS C and AIS D?
Both AIS C and D are motor incomplete injuries. In AIS C, more than half of the key muscle groups below the NLI have a muscle grade less than 3 (cannot move against gravity). In AIS D, at least half of the key muscle groups have a grade of 3 or more (can move against gravity).
What is sacral sparing and why is it important?
Sacral sparing refers to the preservation of any function in the sacral segments (S4-S5): sensation at the S4-S5 dermatome (perianal area), deep anal pressure sensation, or voluntary anal sphincter contraction. The presence of ANY sacral sparing defines an incomplete injury (AIS B, C, or D), which has a better prognosis for recovery than complete injury (AIS A).
What are the different grades of the ASIA Impairment Scale (AIS)?
The AIS classifies spinal cord injury severity into five grades: AIS A (Complete) denotes no motor or sensory function below the neurological level, including sacral segments S4-S5. AIS B (Sensory Incomplete) indicates sensory but no motor function preserved below the neurological level and extending through S4-S5. AIS C (Motor Incomplete) means motor function is preserved below the neurological level, and more than half of key muscles below the NLI have a muscle grade less than 3. AIS D (Motor Incomplete) also has motor function preserved below the neurological level, but at least half of key muscles below the NLI have a muscle grade of 3 or greater. AIS E (Normal) signifies normal motor and sensory function.
How is the neurological level of injury (NLI) determined in a spinal cord injury?
The NLI is the most caudal (lowest) segment of the spinal cord with intact sensory and motor function on both sides of the body, provided that the segments immediately above are normal. It is determined by assessing 28 dermatomes (14 on each side for light touch and pinprick) and 20 key myotomes (10 on each side) during the ASIA exam. For instance, if a patient has normal C5 motor and sensory function, but impaired C6 function, their NLI would be C5.
What specific motor functions are assessed during an ASIA exam to determine motor levels?
The ASIA exam systematically assesses ten key myotomes, five on each side of the body, to determine motor levels and strength. These include C5 (elbow flexors), C6 (wrist extensors), C7 (elbow extensors), C8 (finger flexors), T1 (little finger abductors), L2 (hip flexors), L3 (knee extensors), L4 (ankle dorsiflexors), L5 (long toe extensors), and S1 (ankle plantarflexors). Each muscle group is graded on a 0-5 scale, where 0 represents no contraction and 5 represents normal strength.
Mga Karaniwang Mali na Dapat Iwasan
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- !Classifying injury during spinal shock — reflex absence during spinal shock may make a partial injury appear complete. Retest after bulbocavernosus reflex returns.
- !Confusing the zone of partial preservation (ZPP) with the NLI — ZPP documents partial function below the NLI in complete injuries and should be recorded separately.
- !Not testing deep anal pressure and voluntary anal sphincter contraction, missing sacral sparing that changes AIS grade from A to B.
- !Using patient-reported sensation rather than systematic 28-dermatome bilateral testing, introducing significant inaccuracy.
- !Failing to reassess ASIA grade at standard time points after injury — single measurements are insufficient to characterise recovery trajectory.
- !Confusing the injury level with the skeletal fracture level — they often differ due to spinal cord anatomy relative to vertebral levels.
Pro Tip
Always perform voluntary anal contraction and deep anal pressure sensation testing — these are the definitive tests for sacral sparing that distinguish AIS A from AIS B-D. Omitting these two items is the most common reason for misclassifying a patient as complete (AIS A) when they actually have an incomplete injury with better prognosis.
Alam mo ba?
The ISNCSCI examination has been performed in space — NASA and the International Space Station medical team developed protocols for performing neurological assessments in microgravity environments partly based on ISNCSCI methodology, as spinal cord compression from intervertebral disc herniation is a potential medical emergency during long-duration spaceflight.
Mga Sanggunian
- ›Kirshblum SC et al. International standards for neurological classification of spinal cord injury. J Spinal Cord Med 2011.
- ›American Spinal Injury Association — ISNCSCI Reference Sheet
- ›Fehlings MG et al. Early versus delayed decompression for traumatic cervical spinal cord injury. PLoS Med 2012.
- ›van Middendorp JJ et al. A clinical prediction rule for ambulation outcomes after traumatic spinal cord injury. J Neurotrauma 2010.
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