1. Overview and Description
The International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI), or the International Standards, is the standardized examination which clinicians used to classify neurological impairments.1
It was first established in 1982 by the American Spinal Injury Association (ASIA) Standards utilizing the Frankel Scale to provide precision in classification, and to enhance communication between clinicians and researchers for the National SCI Statistical Center Database.2,3 Being endorsed by the International Medical Society of Paraplegia, it was renamed the International Standards for Neurological and Functional Classification of Spinal Cord Injury, then “Functional” was deleted to become ISNCSCI. It underwent revisions in 1990, 1992, 1996, 2000, 2003 and 2011.4-6 There were also multiple updates, with the latest being in 2015. The revision of worksheet and the introduction of non-key muscle examinations were made with the 2011 revision. The latest version of the ISNCSCI worksheets were established in 2013. The new layout of the 2013 ISNCSCI worksheet now has motor and sensory grouped together according to the body side along with having the myotomes and dermatomes graphically aligned in the respective row by assigned levels. In a study done by Schuld et al, it was found that when new clinicians used the 2013 revised worksheet, as opposed to the 2011 worksheet, there was an improved overall classification performance, specifically in both the motor level and neurological level of injury.7
Spinal cord injury (SCI) affects the conduction of both motor and sensory signals across the site of the lesion, along with affecting the autonomic nervous system. By systematically examining specific dermatomes and myotomes, the clinician can determine the cord segments that have been injured.
Knowing how to perform and interpret the ISNSCI examination is essential to the practice of physical medicine and rehabilitation as it can help give an accurate clinical picture of a person with spinal cord injury by predicting recovery, helping to frame rehab and health care, can provide a diagnosis and is essential for research.
It is very common after spinal cord injury for patients to have concurrent neurological injuries making it essential to perform a complete neurological exam. The complete neurological exam should at minimum include, in addition to the ISNSCI examination, a mini mental status exam, deep tendon reflexes, the cranial nerves and muscle tone.
2. Relevance to Clinical Practice
The ISNCSCI exam, also known as the ASIA (American Spinal Injury Association) examination, is the standard to evaluate and classify individuals with SCI. To begin, have the patient lie supine, in anatomical position.
Light touch and pin prick sensation compose the sensory portion of the examination. Light touch sensation is tested using the stroke of a cotton tip swab <1cm, while sharp/dull or pin prick sensation is tested using a safety pin in 28 dermatomes from C2 to S4-5 on each side.
A diagram of the sensory dermatomes can be found on the AISA website (www.asia-spinalinjury.org). Each sensory dermatome is given a score of 0, 1 or 2. A light touch sensory score of 0 means absent sensation in that dermatome. A score of 1 is given for altered sensation when compared with the face, which serves as the reference point. A score of 2 is given if the sensation is normal, or the same as the face.
For the pin prick portion of the examination, if a patient cannot discriminate sharp versus dull or sensation is absent, this dermatome is given a score of 0. If sharp/dull could be accurately differentiated, but the sensation of sharpness is altered compared to that of the reference point, a score of 1 is given. If both pin prick and the dull sensation feel the same compared to the reference point, that dermatome receives a score of 2.
Key myotomes (a diagram of the myotomes can be found on the AISA exam website www.asia-spinalinjury.org) are tested for the motor component of the exam using the standard muscle function grading scale of 0-5. A score of 0 is given if there is no palpable or visible contraction of muscle. A score of 1 is given for palpable or visible muscle contraction. A score of 2 is given for active movement, with gravity eliminated, through the full range of motion. A score of 3 is given for active movement against gravity throughout the full range of motion. A score of 4 is given for active movement through the full range of motion against gravity and moderate resistance. Finally, a score of 5 is given for active movement through the full range of motion against gravity and sufficient resistance. A key muscle that is either immobilized, has been removed during amputation, is limited by severe pain, or has a contracture that restricts more than 50% of the normal range of motion, can be deemed not testable, or “NT.8“
The next step is determination of the neurological level of injury as follows:
- Determine the sensory level on both the right and left side. This is the most caudal, intact dermatome for both light touch and pin prick sensation, meaning the lowest level that received a score of “2” in both categories.
- Determine the motor levels for the right and left side. The motor level is the lowest key muscle that has a grade of at least 3/5, with all key muscles above that having a grade of 5/5. Note: In areas where there is no key myotome to test (the thorax), the motor level is presumed to be the same as the sensory level, if all testable myotomes above that level are 5/5.
- Determine the neurological level of injury (NLI). The NLI refers to the most caudal level of the spinal cord with intact sensation (grade 2) and antigravity (3/5 or greater) muscle strength, given there is intact sensory and motor function rostrally. An example of a NLI would be written as C7 meaning that the C7 dermatome received scores of 2/2 in both pinprick and light touch sensation, and the C7 myotome received a score of at least 3/5 with all key myotomes rostrally receiving scores of 5/5.8
- First determine if the injury is complete or incomplete. This is determined by testing for anal sensation or motor innervation. The examiner inserts their finger into the rectum and asks the patient to squeeze like they are holding in a bowel movement. If voluntary anal contraction is present, the patient has a motor incomplete injury. Be careful to differentiate between voluntary contraction and the anal reflex, by allowing a few seconds to pass before asking the patient to contract the anal sphincter. Concordantly, if deep anal pressure is intact, meaning the patient can consistently perceive pressure on the anal wall from the examiners finger, the patient has a sensory incomplete lesion. Of note, if the patient already had light touch or pin prick sensation at the S4-5 dermatomes, deep anal pressure does not need to be assessed, but the rectal exam still needs to be performed for the motor component.4
- Determine the ASIA Impairment Scale (AIS) Grade.
There is no motor function or sensation preserved in sacral segments S4-5.
Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-5 (light touch or pin prick at S4-5 or deep anal pressure) AND no motor function is preserved more than three levels below the motor level on either side of the body.
Motor function is preserved below the neurological level and more than half of the key muscles below the NLI have a muscle grade less than 3.
Motor function is preserved below the neurological level and at least half of the key muscle functions below the NLI have a muscle grade of at least 3 or higher.
once sensation and motor function are graded as normal in all segments in a person with prior deficits, they are given an AIS of E. A person without an initial SCI does not receive an AIS grade.
It is important to recognize that for a patient with a grade of C or D, they must either have voluntary anal contraction or sacral sensory sparing with sparing of motor function more than three levels below the motor level for that side of the body.8
Certain clinical pearls when using ISNCSCI include the followings:
- Both key or non-key muscle functions can be used to determine motor incomplete status (differentiation between AIS B from C).
- When distinguishing between a sensory incomplete versus a motor incomplete (AIS B from C) injury, the MOTOR LEVEL on each side is used. When distinguishing between motor incomplete injuries (AIS C from D), the SINGLE NEUROLOGICAL LEVEL is used.
Optional testing includes joint movement appreciation, deep pressure appreciation, and optional motor testing.
Performing the ISNSCI examination in the pediatric population can be both challenging and time consuming. In practice, many children are anxious during the pinprick examination, are unable to remain focused, and lack the ability to provide appropriate responses. But recently, it was found that using only the preselected dermatomes (C4, C6, T4, T6, T10, L2, L4, S1, S3) provided an excellent estimate of the full exam.9 Multiple studies have shown the ISNSCI examination to be reliable in children older than 4 on repeated motor and sensory scores, however, there is still disagreement on the ano-rectal portion of the examination.10
A patient’s neurological classification of spinal cord injury can give the clinicians useful information about the patients’ current level of function while helping to prognosticate functional outcomes. The neurological examination can help to determine if the patient will need assistance breathing, how much independence they will have with maintaining their bowel and bladder, if they will need assistance with transfers, what kind of wheelchair they will require, if they are expected to ambulate, if and how they can communicate, if devices/assistance will be needed for eating, dressing or bathing and how they plan to travel around the community.11
The International autonomic standards is a guideline used to evaluate remaining autonomic function after spinal cord injury by looking at four components: general autonomic, urinary bladder, bowel, and sexual functions.12 A study by Squair et al. investigated how frequently the IAS was used. The study found that even though most spinal cord patients are affected by some sort of autonomic impairment, the IAS was only partially or completely filled out in 63% and 39% of individuals with SCI at time of admission and discharge respectively. This is in contrast to the 93% and 78% of people who used the ISNCSCI. This could be due to the relative newness of the IAS, having only first been conceived in 2009.13
3. Cutting Edge/Unique Concepts/Emerging Issues
One study demonstrated that 75% of ISNCSCI worksheets had at least one error when completed manually, with most errors being made on the motor portion of the exam.14
There are various ways to enhance the accuracy, for example, utilization of a computer algorithm. The Rick Hansen Institute-ISNCSCI Algorithm (RHI-ISNCSCI Algorithm) is a computerized algorithm that aims to provide the correct interpretation of the ISNCSCI neurological exam. Its advantages include improving the accuracy of the classification by correctly deriving the AIS, total motor score and NLI, reducing the time to classify large numbers of cases and providing education to the clinicians. The web interface could eliminate the impact of human error in classifying SCI.15
4. Gaps in Knowledge/Evidence Base
Advancements of training modules, whether in the InSTeP: International Standards online training, or 2-day formal training per European Multicenter Study on Human Spinal Cord Injury (EMSCI),16 should improve the quality of the examination. The ideal training process and experience level are to be investigated.
The ISCNSCI may not reflect the evolution of complex cord function. For example, sensory level deferred motor level is used at myotomes without key muscles. But there can be testable motor function in non-key muscles.17 An article commented that using the high cervical region of C2–C4 is counterintuitive whenever the C5 myotomes are intact.18 There can be deterioration by AIS classification, while neurologic function improves in certain cases.19
A research subcommittee of international clinicians and researchers was formed to review and to revise the ISNCSCI, under the input from the Education Committees of ASIA and ISCoS and approval from the ASIA’s Board of Directors.6 Further modification to define motor level could improve the ISCNCSCI.
- American Spinal Injury Association: International Standards for Neurological Classification of Spinal Cord Injury. Revised 2016. Atlanta, GA.
- American Spinal Injury Association Standards for neurological classification of spinal injured patients. Chicago, IL: ASIA; 1982.
- Frankel HL, Hancock DO, Hyslop G, Melzak J, Michaelis LS, Ungar GH, et al. The value of postural reduction in the initial management of closed injuries in the spine with paraplegia and tetraplegia. Paraplegia 1969;7:179–92.
- International Standards for Neurological Classification of Spinal Cord Injury 2011 Revision. J Spinal Cord Med 2011;34(6):535–46.
- International Standards for the Neurological Classification of Spinal Cord Injury Revised 2011. (Booklet). Atlanta, GA: American Spinal Injury Association.
- Kirshblum SC, Waring W, Biering-Sorensen F et. al. Reference for the 2011 revision of the International Standards for Neurological Classification of Spinal Cord Injury. J Spinal Cord Med. 2011 Nov;34(6):547-54.
- Schuld C, Franz S, Brüggemann K et al. behalf of the EMSCI study group (2016) International standards for neurological classification of spinal cord injury: impact of the revised worksheet (revision 02/13) on classification performance, The Journal of Spinal Cord Medicine, 39:5, 504-512.
- ASIA e=Learning Center. http://asia-spinalinjury.org/learning/. Accessed October 29, 2017.
- Krisa, L., Mulcahey, M.J., Gaughan, J.P., Smith, B. & Vogel, L.C. (2013). Using a limited number of dermatomes as a predictor of the 56-dermatome test of the international standards for neurological classification of spinal cord injury in the pediatric population. Topics in Spinal Cord Injury Rehabilitation, 19(2), 114-20
- Krisa Laura et al. Cerebral Activation During the Test of Spinal Cord Injury Severity in Children: an fMRI Methodological Study Top Spinal Cord Inj Rehabil. 2013 Spring; 19(2): 121–128. Published online 2013 Apr. doi: 10.1310/sci1902-121
- Thomas B, Ragnarsson K, Stein A, Biering-Sorensen F. Spinal Cord Injury. In: Braddom, R. Physical Medicine and Rehabilitation. Philadelphia, PA:Saunders;2011;1308
- Kirshblum S, Anderson K, Krassioukov A, Donovan W. Assessment and Classification of Traumatic Spinal Cord Injury. In:Spinal Cord Medicine. Philadelphia, PA: Lippincott Williams&Wilkins. 2011;85-105
- Squair JW, Nobel G, Noonan VK, Raina G, Krassioukov AV. Assessment of clinical adherence to the international autonomic standards following spinal cord injury. Spinal Cord. 2015. 53, 668-672
- Armstrong AJ, et al. Achieving assessor accuracy on the International Standards for Neurological Classification of Spinal Cord Injury. 2017. Int Spinal Cord Soc.
- Walden K, Bélanger LM, Biering-Sørensen F et. al. Development and validation of a computerized algorithm for International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). Spinal Cord. 2016 Mar;54(3):197-203.
- Schuld C, Wiese J, Franz S et al. Effect of formal training in scaling, scoring and classification of the International Standards for Neurological Classification of Spinal Cord Injury. Spinal Cord. 2013 Apr;51(4):282-8.
- Bjerkefors A, Squair JW, Malik R et. al. Diagnostic accuracy of common clinical tests for assessing abdominal muscle function after motor-complete spinal cord injury above T6. Spinal Cord. 2015 Feb;53(2):114-9.
- Franz S, Kirshblum SC, Weidner N et. al. Motor levels in high cervical spinal cord injuries: Implications for the International Standards for Neurological Classification of Spinal Cord Injury. J Spinal Cord Med. 2016 Sep;39(5):513-7.
- Gündoğdu I, Akyüz M, Oztürk EA et. al. Can spinal cord injury patients show a worsening in ASIA impairment scale classification despite actually having neurological improvement? The limitation of ASIA Impairment Scale Classification. Spinal Cord. 2014 Sep;52(9):719.
Tommy Yu, MD
Nothing to Disclose
Morgan Pyne, DO
Nothing to Disclose