The American Spinal Injury Association: International Standards for Neurological Classification of Spinal Cord Injury

 The ASIA Impairment Scale (AIS) is a multi-dimensional approach to categorize motor and sensory impairment in individuals with SCI (ASIA 2002). Currently in its 6th edition, it identifies sensory and motor levels indicative of the most rostral spinal levels demonstrating “unimpaired” function. Twenty-eight dermatomes are assessed bilaterally using pinprick and light touch sensation and 10 key muscles are assessed bilaterally with manual muscle testing. The results are summed to produce overall sensory and motor scores and are used in combination with evaluation of anal sensory and motor function as a basis for the determination of AIS classification.

Procedure/Administration: A clinical examination is conducted to test whether sensation is 0-absent; 1-impaired; 2-normal. Muscle function is rated from 0-total paralysis to 5-normal (active movement, full ROM against significant resistance).  The presence of anal sensation and voluntary anal contraction are assessed as a yes/no.

How scored: Bilateral motor and sensory levels and the AIS are based on the results of these examinations.

Interpretability: The AIS (5 point ordinal scale), based on the Frankel scale (Frankel et al. 1969), classifies individuals from “A” (complete SCI) to “E” (normal sensory and motor function). Preservation of function in the sacral segments (S4-S5) is key for determining the AIS. The AIS scores are clearly defined and understood by most clinicians. 

Acceptability: 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.

Languages: N/a

Usability: N/a

Time to administer: 20 minutes to conduct/score

Time to score: N/a

Training required: Training is mandatory

Availability: www.asiaspinalinjury.org

Equipment required: No specialized equipment is required.

Summary:

  • ASIA scores are considered essential when classifying persons with SCI as to their neurological status. ASIA scores are routinely collected in administrative data bases such the Model Systems and CIHI National Rehabilitation Reporting System.
  • This is an internationally recognized standard which 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. However, inter-rater reliability for assignment of motor and sensory levels and AIS classifications is less than optimal. Enhanced training methods and materials have been recommended to improve this.

Psychometric Summary:

Reliability

Validity

Responsiveness

Results

Results

Results

Floor/ceiling

TR: Yellow light

Construct: Green light

N/a

N/a

Note: TR= Test re-test; IC= Internal Consistency; Inter-O= Inter-observer; Intra-O= Intra-observer; SS= Sensitivity/Specificity; N/a= No information.

Red light= A single study involving SCI subjects which has less than adequate findings of reliability, validity, and/or responsiveness.

Yellow light= A single study involving subjects with SCI which has adequate to excellent findings of reliability, validity, and/or responsiveness.

Green light= At least 2 studies involving subjects with SCI which have adequate to excellent findings of reliability, validity, and/or responsiveness.

References

  • American Spinal Injury Association: International Standards for Neurological Classification of Spinal Cord Injury, revised 2002. 2002. Chicago, IL, American Spinal Injury Association.
  • Blaustein DM, Zafonte R, Thomas D, Herbison GJ, Ditunno JF. Predicting recovery of motor complete quadriplegic patients. 24 hour v 72 hour motor index scores. Am J Phys Med Rehabil 1993;72:306-311.
  • Cohen ME, Ditunno JF, Jr., Donovan WH, Maynard FM, Jr. A test of the 1992 International Standards for Neurological and Functional Classification of Spinal Cord Injury. Spinal Cord 1998;36:554-560.
  • Cohen ME, Sheehan TP, Herbison GJ. Content validity and reliability of the International Standards for Neurological Classification of Spinal Cord Injury. Top Spinal Cord Inj Rehabil 1996;1:15-31.
  • Frankel HL, Hancock DO, Hyslop G, Melzak J, Michaelis LS, Ungar GH, Vernon JD, Walsh JJ. The value of postural reduction in the initial management of closed injuries of the spine with paraplegia and tetraplegia. Paraplegia 1969;7:179-192.
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  • Jonsson M, Tollback A, Gonzales H, Borg J. Inter-rater reliability of the 1992 international standards for neurological and functional classification of incomplete spinal cord injury. Spinal Cord 2000;38:675-679.
  • Lazar RB, Yarkony GM, Ortolano D, Heinemann AW, Perlow E, Lovell L, Meyer PR. Prediction of functional outcome by motor capability after spinal cord injury. Arch Phys Med Rehabil 1989;70:819-822.
  • Marino RJ, Graves DE. Metric properties of the ASIA motor score: subscales improve correlation with functional activities. Arch Phys Med Rehabil 2004;85:1804-1810.
  • Priebe MM, Waring WP. The interobserver reliability of the revised American Spinal Injury Association standards for neurological classification of spinal injury patients. Am J Phys Med Rehabil 1991;70:268-270.
  • van Middendorp JJ, Hosman AJF, Pouw MH, EM-SCI Study Group, and Van de Meent H. ASIS impairment scale conversion in traumatic SCI: is it related with the ability to walk? A descriptive comparison with functional ambulation outcome measures in 273 patients. Spinal Cord 2009; 47: 555-560.