Predictors of Walking

Many people with SCI are interested in regaining the ability to walk to maintain independence in their lives. Considerable progress has been made in predicting who will or will not be able to walk post-SCI.

Defining Walking Recovery after SCI

To determine if someone with SCI can engage in walking training, you will need to know their neurological status, the completeness/incompleteness of their SCI, and some empirical data from their attempts to stand and/or maintain balance beforehand. There are of course ways to engage in these activities safely, with multiple spotters (i.e., nurses/physical therapists) present, and/or using assistive technologies like hydraulic lifts, body-weight support systems, standing frames, parallel bars, or walkers.

Functional ambulation has been defined as “the capacity to walk reasonable distances in and out of home unassisted by another person,” (Hussey & Stauffer 1973) and “the ability to walk, with or without the aid of appropriate assistive devices (such as prostheses, orthoses, canes or walkers), safely and sufficiently to carry out mobility-related activities of daily living” (Stroke Engine 2025).

Regaining the ability to walk after SCI is not a ‘one size fits all’ prospect; there are many things for the health care professional and the person with SCI to consider. For example, there may be differences in strength, sensation, and motor ability between the right leg and the left leg, which could compromise step length/cadence, walking symmetry, and balance putting the person with SCI at risk for falling and further injury. Someone with incomplete SCI who can walk may be safe to stand and walk in their own home, but may not be able to walk far enough to get from where their car is parked to their place of work, or they may not be able to walk fast enough to cross a street before the traffic lights change.

Tests Used to Measure Walking Ability in People with SCI

A number of tests, or Outcome Measures, have been validated to test walking ability in people with SCI.

Timed tests include:

• Timed Up & Go (TUG) test measures the time in seconds it takes someone to stand up from an armchair, walk 3 meters, return to the chair, and sit down. This test was originally developed as a clinical measure of balance in elderly people.13
• Ten Meter Walk Test (10MWT) measures the time in seconds that it takes a people to walk 10 meters (i.e., assessing short-duration walking speed).
• Six Minute Walk Test (6MWT) measures the distance in meters walked within 6 minutes. This test is useful in assessing how far people can walk safely continuously (i.e., walking duration) in addition to getting an approximation of cardiovascular exercise capacity.

Functional walking tests include:

• Walking Index for Spinal Cord Injury II (WISCI-II) an ordinal scale that quantifies a person’s walking ability; the lowest score of 0 indicates that a person cannot stand and walk and the highest score of 20 is assigned if a person can walk more than 10 meters without walking aids or assistance.
• SCI Functional Ambulation Inventory (SCI-FAI) – walking ability is measured by three components: gait parameter (weight shift, step width, step rhythm, step height, foot contact, step length), assistive devices use (degree of assistance provided by each device (e.g., cane, walker, parallel bars)), and walking mobility (walking distance, speed, and walking frequency).
• The Spinal Cord Independence Measure (SCIM) – Scale developed to measure the functional abilities of people with SCI and their level of independence when performing basic activities of daily living. The walking related items comprise the SCIM-Mobility subscale, useful for functional walking determination because they are scored based on the level of assistance need by the walker (e.g., 0 = total assistance; 1 =electric wheelchair or partial assistance to operate manual wheelchair; to 6 = walks with 1 cane; 7 = needs leg orthosis only; and 8 = walks without aid).

There is some research to show what walking speeds are safe for different levels of ambulation. Van Hedel et al. (2009)created 5 functional ambulation categories from the SCIM Mobility items and subsequently timed all participants to determine threshold times for grouping walkers with SCI. They found:

1. With a minimum walking speed of 0.09 ± 0.01 m/s, a person with SCI would be considered a “supervised walker.”
2. With a minimum walking speed of 0.15 ± 0.08 m/s, a person with SCI would be considered an “indoor walker.”
3. With a minimum walking speed of 0.44 ± 0.14 m/s, a person with SCI would be considered an “assisted walker.”
4. To be considered a “walker who does not use a walking aid”, a minimal walking speed of 0.70 ± 0.13 m/s is required. This is also the threshold that clinicians may consider a person with SCI “functional ambulation” or safe for walking in the community.

Severity of Spinal Cord Injury Lesion and ASIA Impairment Scale

The most important variable in determining walking capabilities will be neurological level and completeness/severity of injury. The standard assessment of the severity and level of SCI is the International Standards of Neurological Classification of Spinal Cord Injury (ISNCSCI). The ISNCSCI is (ideally) performed within 72 hours of a SCI to allow clinicians to determine the neurological level and completeness of injury through testing of voluntary movements and pinprick/light touch sensation. The ASIA Impairment Scale (AIS) defines complete and incomplete spinal cord lesions, remaining sensory or motor function, and classifies people on a 5-level ordinal scale:

• A: Complete. No sensory or motor function is preserved in the sacral segments S4-S5.
• B: Sensory incomplete. Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5 (light touch, pin prick at S4-S5 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 below the neurological level and more than half of key muscle functions below the single neurological level of injury (NLI) have a muscle grade less than 3.
• D: Motor incomplete. Motor function is preserved below the neurological level and at least half of key muscle functions below the NLI have a muscle grade of 3 or greater.
• 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.

In a review of all walking-related predictor literature in people with SCI, Scivoletto et al. (2014) provided the following conclusions:

• AIS A:
  • Limited possibilities of achieving walking, however of people who convert from complete to incomplete injury, 14% may regain some walking function (usually limited to those with injuries from T12 to L3, orthoses/braces or other devices may be required, and the speed at which they may walk will likely be slow and require great energy, so may not be ‘functional.’ (van Middendorp et al. 2009; Ditunno et al. 2008; Vaccaro et al. 1997).
• AIS B:
  • An estimated 33% of people may recover walking ability. Pinprick preservation seems to be a positive factor compared to light touch sensitivity, suggesting less extensive damage to the spinothalamic tracts and posterior column (Foo et al., 1981; Crozier et al. 1991; Waters et al. 1994; Katoh and el Masry 1995; Oleson et al. 2005).
• AIS C:
  • Around 75% have a positive prognosis for walking, especially in those with lower thoracic and lumbar level injuries, though orthoses/braces or other assistive devices will likely be necessary. Age is a stronger predictor at AIS C than in other levels, with 80-90% of people younger than 50 more likely to walk versus 30-40% in those over 50 (Maynard et al. 1979; Crozier et al. 1991; Waters et al. 1994; van Middendorp et al. 2009; Waters et al, 1994; Perot and Vera 1982; Foo, 1986; Burns et al. 1997; Scivoletto et al. 2003).
• AIS D:
  • Very good likelihood of walking at rehabilitation discharge and at 1-year post-injury (Burns et al. 1997; Scivoletto et al. 2003; van Middendorp et al. 2009).

Specific Walking Prediction Models in People with SCI

Some research provides more precise prediction models for walking in people with SCI based on remaining neural activity in specific myotomes and muscles. Van Middendorp (2011; N=640) produced a prediction rule using the motor scores and light touch scores at both L3 (quadriceps femoris – knee extensor) and S1 (gastrocsoleus – plantar flexor) and age of the person with SCI. This data had excellent discrimination and accurately distinguished independent walkers, dependent walkers, and non-walkers (area under the curve 0.956, 95% CI 0.936–0.976, p<0.0001). Hicks (2017; N= 278) tested a simplified model of Van Middendorp’s prediction rule on Rick Hansen Spinal Cord Injury Registry (RHSCIR) data set, using only L3 motor score, S1 light touch score, and age as a dichotomized variable (older/younger than 65 years). The simplified Hicks three variable model had an overall classification accuracy of 84%, with 76% sensitivity and 90% specificity.

More recently, two additional prediction models have emerged using similar variables. Draganich et al. (2023; N=3721) used L3 motor score, L5 motor score (big toe extensor), and S1 light touch as inputs and they were able to predict outdoor walking capabilities at 1-year post-SCI 84.9% of the time. Cathomen et al. (2023; N=361) used L2 and L3 myotomes to differentiate between walkers and non-walkers. They found that 85% of patients with a motor score in the L2 myotome of 1 or higher achieved ambulatory capacity throughout rehabilitation, and for the L3 myotome the proportion was 88%.

Accurately assessing someone’s SCI level of injury and completeness, as well as using these prediction rules may useful for clinical decision-making in rehabilitation. For example, if someone with SCI is more likely to walk based on these parameters, then intensive walking training would more likely be useful to be prescribed. Conversely, if someone is less likely to walk based on these parameters, then a rehabilitation program focusing on wheelchair skills, transfers, and other compensatory strategies would likely be the most useful course of action (Draganich et al. 2023).