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
An international standard 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, 2019.1,4-6 There were also multiple updates, with the latest being in 2015. Revision of the worksheet and the introduction of non-key muscle examinations were made with the 2011 revision4-6. The new layout of the 2013 ISNCSCI worksheet grouped motor and sensory 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 The latestversion of the ISNCSCI worksheet is the 2015 update. This update repositioned the dermatomal map of key sensory points C6-C8 in the middle of the page as well as added a section on when to test non-key muscles. It also added clarification of the 2011 revisions including the appropriate use of the term “not determinable”, revision of the term “motor incomplete” and the non-key muscle function and their corresponding myotomes, as well as the rules for their use. The 2019 revision brought two main changes: a new taxonomy for documenting non-SCI related conditions and an updated definition on when to apply the zone of partial preservation.8
Spinal cord injury (SCI) can affect 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 care of individuals with SCI in 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 rehabilitation and health care, as well as help provide a diagnosis. The ISNCSCI examination is also essential for research and will continue to evolve as SCI medicine advances.8
It is very common after spinal cord injury for patients to have other 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.
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 (Figure 1).
The dermatome chart per the International Standards for Neurological Classification of Spinal Cord Injury worksheet.1 Permission to use received from the American Spinal Injury Association: International Standards for Neurological Classification of Spinal Cord Injury, revised 2019; Richmond, VA.
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 (Figure 1) 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”.9
For patients with pre-existing or concomitant musculoskeletal, neurological, or other non-SCI conditions, abnormal motor scores should be tagged with an asterisk, “*”, to indicate an impairment due to the condition. Examples of non-SCI conditions include previous trauma (amputations), prior neurological deficits from cerebrovascular accidents (CVA), chronic peripheral nerve injuries, pain, or debility. The asterisk (“*”) may be applied in motor scores ranked 0, 1, 2, 3, 4, or NT; the utility of the 5* score remains under review through clinical studies and is currently not being utilized in practice. Additionally, the asterisk (“*”) may be applied to sensory scores ranked 0, 1, or NT. If the examiner indeed labels a score with the “*”, the non-SCI condition should be explained and specified in the comments box on the front side of the ISNCSCI worksheet. As such, information regarding how the score is rated for classification purposes should be dictated. For “*” scores above the sensory/motor level, these cases will, in most cases, be handled as normal during classification. For “*” scores at or below the motor/sensory level, those scores will likely be handled as not normal given the superimposition of the non-SCI condition to the deficits produced by the SCI. Therefore, any motor or sensory level, NLI, or AIS grade that is affected by a “*” score should additionally be labeled with a “*” to clearly indicate the aforementioned classification(s) is/are based on clinical interpretations of the subjective and objective score(s).9
The next step is determination of the neurological level of injury as follows:
1. Determine sensory levels for right and left sides. This is the most caudal, intact dermatome for both light touch and pin prick sensation (score of 2).
2. Determine motor levels for right and left sides. Defined by the lowest key muscle function that has a grade of at least 3, providing all key muscle functions represented by segments above that level are judged to be intact graded as 5. Note: In regions where there is no key myotome to test, the motor level is presumed to be the same as the sensory level, if testable motor function above that level is also normal.
3. Determine the neurological level of injury (NLI). This refers to the most caudal segment of the cord with intact sensation (grade 2) and antigravity (3 or greater) muscle function strength, provided that there is normal (intact) sensory and motor function rostrally. The NLI is the most cephalad of the sensory and motor levels determined in steps 1 and 2.
4. 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.
5. Determine the ASIA Impairment Scale (AIS) Grade.
Is injury Complete? If YES, AIS = A
Is injury Motor Complete? If YES, AIS = B
NO ↓ (No = voluntary anal contraction OR motor function more than three levels below the motor level on a given side. If the patient has sensory incomplete classification)
Are at least half (half or more) of the key muscles below the neurological level of injury graded 3 or better?
NO ↓ YES ↓
If sensation and motor function is normal in all segments, AIS=E
(Note: AIS E is used in follow-up testing when an individual with a documented SCI has recovered normal function. If at initial testing no deficits are found, the individual is neurologically intact and the AISA Impairment Scale does not apply.)
6. Determine the zone of partial preservation (ZPP).
The ZPP is used only in injuries with absent motor (No DAP, no LT and no PP sensation) in the lowest sacral segments S4-5 and refers to those dermatomes and myotomes caudal to the sensory and motor levels that remain partially innervated. With sacral sparring of sensory function, the sensory ZPP is not applicable and therefore “NA” is recorded in the block of the worksheet. Accordingly, if VAC is present, the motor ZPP is not applicable and is noted as “NA”.
A=Complete. No sensory or motor function is 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.
C=Motor Incomplete. Motor function is preserved at the most caudal sacral segments for voluntary anal contraction (VAC) OR the patient meets the criteria for sensory incomplete status (sensory function preserved at the most caudal sacral segments S4-5 by LT, PP or DAP), and has some sparring of motor function more than three levels below the ipsilateral motor level on either side of the body. (This includes key or non-key muscle functions to determine motor incomplete status) For AIS C- less than half of key muscle functions below the single NLI have a muscle grade ≥ 3.
D=Motor Incomplete. Motor incomplete status as defined above, with at least half (half or more) of key muscle functions below the single NLI having a muscle grade ≥ 3.
E=Normal. If sensation and motor function as tested with the ISNCSCI are graded as normal in all segments, and the patient had prior deficits, then the AIS grade is E. Someone without an initial SCI does not receive an AIS grade.
Using ND: To document the sensory, motor and NLI levels, the ASIA Impairment Scale grade, and/or the zone of partial preservation (ZPP) when they are unable to be determined based on the examination results. Certain clinical pearls when using ISNCSCI include the followings1
- 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.
- Motor ZPP does not follow sensory function (applicable in regions where there is no key muscle to test).
- It is possible that a person with a neurologically complete injury can ambulate. The purpose of ISNCSCI is the determination of neurological level and severity of SCI, and it is not a functional measure.
- ZPPs are some of the most important predictors of neurological recovery.
- In 2019 ZPP rules were modified and are no longer based on AIS grade. Motor ZPP are now defined and should be documented in all cases including patients with incomplete injuries with absent VAC.
- When non-key muscles are used to determine AIS C classification, motor ZPP in most distal non-key muscles is recorded.
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.10 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.11
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.12
The International autonomic standards (IAS) 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.13 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 2009.14
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.15
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.16 The multicenter study about spinal cord injury (EMSCI) ISNCSCI calculator is another validated tool, which was validated in other languages too.17,18
The expedited ISNCSCI (E-ISNCSCI) protocol was published on the ASIA website in February, 2020.19 It aims at defining the neurological level of injury and the AIS using the fewest exam items. This is achieved by omitting part of the exam and/or substituting S1 sensory and motor findings for the anorectal exam and S4-5 dermatomes. The standard ISNCSCI and the E-ISNCSCI protocols could produce conflicting AIS classifications, but NLI would likely be comparable. Caution is required to avoid replacing the standard protocol with the E-ISNCSCI in settings such acute inpatient, admission and discharge from rehabilitation. Please refer to the ASIA website for detailed instructions on performing the E-ISNCSCI.19
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),17 should improve the quality of the examination. The ideal training process and experience level are to be investigated. Besides these, working through challenging cases can help clarifying some of the latest revisions.20
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.21 Additionally, one article has indicated that using the high cervical region of C2–C4 is counterintuitive whenever the C5 myotomes are intact.22 Furthermore, decline in AIS classification can occur amid improved neurologic function in certain cases.23
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 Ongoing research seeking insight on the utility of the 5* score through clinical studies and is not currently being utilized in practice.
- American Spinal Injury Association: International Standards for Neurological Classification of Spinal Cord Injury, Revised 2019; Richmond, VA.
- 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.
- Kirshblum S, Snider B, Rupp R, et. al. Updates of the International Standards for Neurologic Classification of Spinal Cord Injury. Physical Medicine and Rehabilitation Clinics of North America. 2020 Aug;31(3):319-330.
- ASIA and ISCoS international standards committee. The 2019 revision of the International Standards for Neurological Classification of Spinal Cord Injury – What’s new? Spinal Cord (2019, 57: 815-817).
- 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
- Schuld C, Franz S, Schweidler J et. al. Implementation of multilingual support of the European Multicenter Study about Spinal Cord Injury (EMSCI) ISNCSCI calculator. Spinal Cord. 2022; 60:37-44.
- Expedited ASIA ISNCSCI Exam (E-ISNCSCI) Version 1. February 2020. https://asia-spinalinjury.org/expedited-isncsciexam/.Accessed 8 Feb 2022.
- Kirshblum S, Read M. Classification Challenges of the 2019 Revised International Standards for Neurological Classification of Spinal Cord Injury. Spinal Cord (2022 60:11-17).
- 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.
Original Version of the Topic
Tommy Yu, MD, Morgan Pyne, DO. Neurological examination and classification of SCI. 2/15/2018
Tommy Yu, MD
Nothing to Disclose
Morgan Pyne, DO
Nothing to Disclose
Samantha Mendelson, DO
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Matthew Wilhelm, DO
Nothing to Disclose