ASIA Impairment Scale in Ontario Spinal Cord Injury Claims: AIS A, B, C, D and E Explained

The ASIA Impairment Scale, also called the AIS grade, is used to classify the severity of a spinal cord injury as AIS A, B, C, D or E. In Ontario spinal cord injury claims, the AIS grade helps explain whether the injury is complete or incomplete, how much motor or sensory function remains, whether there is sacral sparing, and how the injury affects prognosis, future care, attendant care, income loss and catastrophic impairment.

For a broader overview of claims involving paralysis, incomplete spinal cord injuries, catastrophic impairment and long-term care needs, see our page for Ontario spinal cord injury lawyers.

What Is the ASIA Impairment Scale?

ASIA stands for the American Spinal Injury Association. The ASIA Impairment Scale is part of the International Standards for Neurological Classification of Spinal Cord Injury, often shortened to ISNCSCI.

Doctors and rehabilitation teams use the ASIA system to classify spinal cord injuries based on neurological function. The assessment looks at motor strength, light touch sensation, pin prick sensation, neurological level of injury, sacral function and whether the injury is complete or incomplete.

In practical terms, the ASIA grade helps answer questions such as:

Is the spinal cord injury complete or incomplete?

Is there sacral sparing?

Is there sensation in the S4-S5 sacral segments?

Is there voluntary anal contraction?

Is there deep anal pressure?

Is any motor function preserved below the neurological level of injury?

Is the person classified as AIS A, AIS B, AIS C, AIS D or AIS E?

Has neurological function improved, worsened or stayed the same over time?

These types of findings are important in both accident benefits claims and lawsuits. The ASIA grade is not determinative of important in and itself. Spinal cord injury claims still depend on imaging, treatment records, surgical records, rehabilitation evidence, functional limitations, work capacity, attendant care needs and long-term prognosis. But the ASIA classification gives doctors, lawyers, insurers and experts a common language for discussing the severity of the spinal cord injury.

What Does AIS A Mean?

AIS A usually describes a complete spinal cord injury. This means there is no preserved motor or sensory function in the lowest sacral segments, S4-S5. The person does not have sacral sparing.

This is the most severe ASIA classification. A person with an AIS A injury can have paraplegia or tetraplegia, depending on the level of injury. The long-term effects can include paralysis, loss of sensation, bowel and bladder dysfunction, sexual dysfunction, spasticity, neuropathic pain, pressure sore risk, respiratory complications, loss of independence and major future care needs.

In Ontario personal injury claims, an AIS A spinal cord injury usually requires detailed evidence about future care, attendant care, home modifications, mobility equipment, medical complications, income loss and the person’s long-term loss of independence.

What Does AIS B Mean?

AIS B describes a sensory incomplete spinal cord injury. This means sensory function is preserved below the neurological level of injury, including the sacral segments, but motor function is not preserved below the level required for a motor incomplete classification.

AIS B injuries are still devastating. The person can have paralysis, major mobility loss, bowel and bladder impairment, neuropathic pain, sexual dysfunction, loss of work capacity and extensive care needs. The fact that sensation remains does not mean the injury is minor.

In a legal claims, AIS B designations are extremely important because it shows the injury is incomplete, but still extremely serious. It can also affect prognosis, rehabilitation evidence, catastrophic impairment analysis and the way future care needs are assessed.

What Does AIS C Mean?

AIS C describes a motor incomplete spinal cord injury. This means some motor function is preserved below the neurological level of injury, but the strength in key muscles below that level remains significantly limited.

AIS C injuries vary widely. Some people can recover partial movement but remain unable to walk safely. Others regain some leg or arm movement but continue to need a wheelchair, walker, brace, transfer equipment, attendant care or help with daily routines.

AIS C is important in Ontario spinal cord injury claims because it often sits in the space between obvious catastrophic paralysis and complicated functional impairment. A person can have some movement and still face permanent disability.

The claim should not be reduced to whether the person can move a limb. The better questions are:

Can the person walk safely and reliably?

Can the person transfer independently?

Can the person use stairs?

Can the person manage bowel and bladder routines?

Can the person bathe, dress, cook and leave the home safely?

Can the person return to their actual job?

Does pain, spasticity, fatigue or weakness limit daily function?

Those details drive the value of the claim more than the letter grade.

What Does AIS D Mean?

AIS D is also a motor incomplete spinal cord injury, but it generally indicates stronger preserved motor function than AIS C. AIS D is sometimes misunderstood because the person has enough preserved strength in many key muscles to suggest a better neurological recovery than AIS A, B or C. That does not mean the person has recovered. It does not mean the injury is mild. It does not mean the claim is small.

A person with AIS D can still have serious permanent impairment. They can have impaired walking, poor balance, weakness, falls, spasticity, neuropathic pain, bowel dysfunction, bladder dysfunction, sexual dysfunction, fatigue, hand dysfunction, reduced endurance and inability to return to physical work.

Some people with AIS D can walk short distances indoors but remain unsafe outdoors. Some can walk during therapy but cannot manage real-world distances, winter conditions, uneven ground, crowds, curbs, stairs or emergency situations.

Some require a cane, walker, wheelchair, scooter, orthotics, bathroom equipment, vehicle changes or home modifications.

In Ontario catastrophic impairment analysis, AIS D deserves careful attention. An AIS D classification does not automatically end the catastrophic impairment analysis. The Accident Benefits spinal cord injury route includes additional functional criteria for some AIS D cases, including serious indoor mobility limitations and certain bowel or bladder impairments.

For that reason, an AIS D spinal cord injury claim should be assessed through both the ASIA grade and the person’s real-world function.

What Does AIS E Mean?

AIS E means motor and sensory function are normal on the ASIA examination.

This does not always mean the person has no symptoms, no pain or no legal claim. AIS E means the standardized motor and sensory findings tested through the ASIA exam are normal at the time of assessment.

A person can have an earlier documented spinal cord injury and later improve to AIS E. A person can also have ongoing pain, stiffness, reduced endurance, psychological trauma, work limitations or other injury-related problems that are not captured by the ASIA grade alone.

Why Sacral Sparing Is Important

Sacral sparing is one of the key concepts in the ASIA system. The sacral segments S4-S5 are the lowest segments tested in the neurological classification. If there is preserved sensory or motor function in those sacral segments, the injury is generally classified as incomplete rather than complete.

Medical records may refer to sacral sparing, S4-S5 sensation, voluntary anal contraction, deep anal pressure, light touch or pin prick sensation. These terms can look technical, but they often answer a crucial question: is any neurological function preserved at the lowest sacral level?

That distinction can affect diagnosis, prognosis, rehabilitation planning, catastrophic impairment evidence and the long-term assessment of care needs.

In a legal claim, sacral sparing is not just a medical detail buried in a chart. It can shape the way the spinal cord injury is classified and explained.

What Is the Neurological Level of Injury?

The neurological level of injury is the lowest level of the spinal cord where motor and sensory function remain normal on both sides of the body. This is different from the level of a vertebral fracture, disc herniation or MRI finding.

For example, imaging could describe cord compression, edema, hemorrhage, myelomalacia, a fracture-dislocation or disc injury at a specific spinal level. The neurological exam looks at how the spinal cord injury affects function in the body.

The neurological level of injury can affect:

arm and hand function

trunk control

walking

wheelchair use

transfers

bowel and bladder control

sexual function

breathing

skin integrity

daily independence

return to work

future care needs

A cervical spinal cord injury can affect the arms, hands, trunk, legs, bowel, bladder, sexual function and independence with daily care.

A thoracic spinal cord injuries affect trunk control, leg function, sensation below the chest or abdomen, bowel function and bladder function. A lumbar or sacral injury can affect leg strength, walking, sensation, bowel control, bladder control, sexual function and chronic pain.

Complete vs. Incomplete Spinal Cord Injury

The ASIA system helps distinguish between complete and incomplete spinal cord injuries. A complete spinal cord injury generally means there is no preserved motor or sensory function in the lowest sacral segments, S4-S5. This usually corresponds to AIS A.

An incomplete spinal cord injury means some motor or sensory function remains below the neurological level of injury. Incomplete spinal cord injuries include AIS B, AIS C and AIS D.

Incomplete does not mean minor. Both can cause life-changing impairment. Incomplete spinal cord injuries involve severe weakness, impaired walking, loss of hand function, spasticity, neuropathic pain, bowel dysfunction, bladder dysfunction, sexual dysfunction, fatigue, reduced independence and inability to return to work.

A complete spinal cord injury often creates more obvious permanent functional loss, but the legal analysis still depends on the person’s actual life: care needs, work loss, home changes, medical complications, family impact and long-term prognosis.

How the ASIA Grade Affects an Ontario Spinal Cord Injury Claim

The ASIA grade can affect several parts of an Ontario spinal cord injury claim.

Severity of injury

The AIS grade helps classify the neurological injury. It can show whether the spinal cord injury is complete, sensory incomplete or motor incomplete.

Prognosis

AIS A, B, C and D injuries often have different recovery patterns. Prognosis still depends on the person, the level of injury, age, surgery, complications, rehabilitation progress and the course of recovery.

Rehabilitation needs

The ASIA classification can help rehabilitation teams understand mobility, transfers, balance, upper limb function, bowel and bladder needs, skin risks and future therapy needs.

Attendant care

A person with a spinal cord injury can need help with transfers, bathing, dressing, toileting, bowel routines, bladder routines, meal preparation, medication, skin checks, mobility and transportation.

Future care costs

The AIS grade can assist experts in explaining future therapy, equipment, home modifications, attendant care, mobility devices, vehicle changes, medical supplies and long-term support.

Income loss

Spinal cord injury does not affect work only by limiting walking. Hand function, sitting tolerance, pain, fatigue, bowel and bladder routines, medication effects, transportation barriers and secondary complications can all affect employability.

Catastrophic impairment

In motor vehicle accident cases, the ASIA grade can be directly relevant to catastrophic impairment under Ontario’s accident benefits system.

ASIA Grades and Catastrophic Impairment in Ontario

Catastrophic impairment is important in Ontario motor vehicle accident cases because it can open access to a higher level of accident benefits.

For spinal cord injuries, the SABS includes a catastrophic impairment category for paraplegia or tetraplegia. The regulation uses the person’s permanent grade on the ASIA Impairment Scale as part of that route.

Paraplegia or tetraplegia definitely meet the spinal cord injury catastrophic impairment route where the person’s neurological recovery has reached the point that the permanent ASIA grade can be determined and the permanent grade is AIS A, B or C.

AIS D is treated differently. AIS D can qualify under the spinal cord injury route if additional functional criteria are met, including serious indoor mobility limitation on the Spinal Cord Independence Measure or specified neuro-urological or anorectal impairment.

The catastrophic analysis depends on the SABS, the timing of the assessment, neurological recovery, functional evidence, mobility, bowel function, bladder function, treatment records and expert opinion.

People with serious spinal cord injuries should have the catastrophic impairment issue assessed carefully, especially where the records mention AIS A, AIS B, AIS C, AIS D, paraplegia, tetraplegia, sacral sparing, neuro-urological impairment or bowel routine.

Why the ASIA Grade Is Not the Same as Settlement Value

The ASIA grade helps explain severity, but it does not decide settlement value by itself. Settlement value depends on liability, insurance limits, age, pre-accident income, work history, prognosis, home setup, family support, care needs, medical complications, future income loss, future care costs, pain and suffering, out-of-pocket expenses and the availability of accident benefits.

A young tradesperson with hand weakness after a cervical spinal cord injury can have a very different income loss claim than a retired person with the same grade.

A person with bowel and bladder impairment can require lifelong supplies, routines, monitoring and attendant support. A person who can walk short distances indoors can still need major changes to their work, transportation, housing and daily life.

What Evidence Helps Prove the Severity of a Spinal Cord Injury?

A strong Ontario spinal cord injury case usually requires more than one diagnosis or one imaging report.

Important evidence includes:

hospital records

emergency department records

ambulance records

neurosurgical records

orthopedic spine records

MRI reports

CT reports

operative reports

rehabilitation records

physiatry records

occupational therapy reports

physiotherapy records

urology records

bowel and bladder documentation

pain records

medication records

attendant care assessments

home modification reports

vocational assessments

family evidence about daily function

Expert evidence is frequently needed. Depending on the case, this can include a physiatrist, neurologist, neurosurgeon, occupational therapist, life care planner, vocational expert, economist or future care expert.

The ASIA grade helps classify the neurological injury. The rest of the evidence shows how that injury affects mobility, independence, care, work, relationships and long-term quality of life.

Why Timing of the ASIA Assessment Matters

Spinal cord injury classification can change over time. Early after trauma, the medical picture can be affected by swelling, spinal shock, surgery, pain, medication, sedation, other injuries or limited ability to participate in testing. A person’s early AIS grade is not always the same as the later grade.

That is why the timing of the neurological examination matters.

For catastrophic impairment in Ontario, SABS spinal cord injury route focuses on the person’s permanent ASIA grade. For the lawsuit, long-term prognosis and real-world function are central.

Lawyers reviewing spinal cord injury claims should look at the progression of the evidence:

What was the initial AIS grade?

Did the grade change during rehabilitation?

Was there sacral sparing?

Was the injury classified as complete or incomplete?

Did MRI show cord signal change, compression, edema, hemorrhage or myelomalacia?

Did the person regain movement but remain unsafe walking?

Did bowel or bladder impairment continue?

Did the person remain unable to return to work?

Did the person need attendant care, equipment or home modifications?

Those details change the way the claim is valued.

Common Medical Terms Seen With ASIA Grading

People often first see the ASIA Impairment Scale in a hospital note, rehabilitation record, catastrophic impairment report or medical-legal assessment. The same records can include other spinal cord injury terms.

Sacral sparing

Preserved motor or sensory function in the lowest sacral segments. This is important when deciding whether the injury is complete or incomplete.

S4-S5

The lowest sacral segments tested in the ASIA classification.

Voluntary anal contraction

A motor finding used in the neurological classification.

Deep anal pressure

A sensory finding used in the neurological classification.

Neurological level of injury

The lowest level where motor and sensory function remain normal on both sides.

Motor incomplete

Spinal cord injuries where motor function is preserved below the neurological level. AIS C and AIS D are motor incomplete classifications.

Sensory incomplete

A spinal cord injury where sensory function remains below the neurological level, but motor function is not preserved in the same way. AIS B is sensory incomplete.

Paraplegia

Impairment or paralysis affecting the lower part of the body, usually from a thoracic, lumbar or sacral spinal cord injury.

Tetraplegia

Impairment or paralysis affecting all four limbs, usually from a cervical spinal cord injury. Some records also use the term quadriplegia.

Speak With an Ontario Spinal Cord Injury Lawyer

The ASIA Impairment Scale is commonly referenced during Ontario spinal cord injury claims. Hover, the ratings should be interpreted alongside imaging, surgical records, rehabilitation progress, bowel and bladder evidence, functional testing, work evidence and the person’s actual daily limitations.

Foster Injury Law can represent individuals with serious spinal cord injuries across Ontario. If you or someone close to you suffered a spinal cord injury after an accident, contact Foster Injury Law for a free personal injury consultation with an Ontario spinal cord injury lawyer.

Author

This article was written by Lane Foster of Foster Injury Law, an Ontario personal injury law firm representing people with serious spinal cord injuries, catastrophic injuries, amputations, brain injuries and other life-changing trauma.