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Objective: Recent studies on conversion of ASIA Impairment Scale (AIS) grades report higher rates of conversion than older studies. The purpose of this study is to examine the rate of conversion over time in persons with ASIA Impairment Scale (AIS) grade A spinal cord injury (SCI), accounting for level of injury.

Methods: Subjects were injured between 1995 and 2015, enrolled in the National SCI Database as Day-1 admissions, at least 16 years old at the time of injury, classified as AIS A, and had an initial examination within 2 weeks of injury. Change in AIS grade was determined for subjects who had followup examinations at least 30 days post injury. Subjects were grouped in 3-year intervals and trends in AIS grade conversion were assessed for the total sample and by tetraplegia (Tetra), high paraplegia (T1-9, HPara) and low paraplegia (T10-12, LPara).

Results: There were 2037 subjects with usable initial examination data, of whom 1877 had a follow up examination. Average age at injury was 35.0 +/-15.4 years, 79.8% were male, 44.6% Tetra, 35.3% HPara, 20.1% LPara. Overall 80.8% remained AIS A at follow-up, with 8.8% converting to motor incomplete. Change in AIS grade differed by level of injury: 71.4%, 90.9% and 83,2% of Tetra, HParaand LPararemained AIS A, with 13.5%, 4.5% and 6.1% respectively converting to motor incomplete. There was a strong trend towards increased rates of conversion over time, especially for persons with Tetra (p<0.01 for all groups). For Tetra, conversion rates to incomplete (AIS B-E) were 17.6% in the 1995-1997 period increasing to 50% in the 2013-2015 period, while conversion rates to motor incomplete (AIS C-E) were 9.4% increasing to 28.1% at these times. For Hparaover the same periods conversion rates to incomplete changed from 5.3% to 17.6% and to motor incomplete from 3.0% to 6.8%. LParaconversion rates to incomplete changed from 8.0% to 23.1% and to motor incomplete from 2.7% to 15.4%.

Conclusion: Although there is some variability in rates, conversion from complete to incomplete or motor incomplete has been increasing over time, particularly for persons with tetraplegia.

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SCI, traumatic spinal cord injury, spinal cord injury, complete spinal cord injury, ASIA Impairment Scale Conversion


Medicine and Health Sciences | Rehabilitation and Therapy


Presented at the April 2019 American Spinal Injury Association SCI Summit, Annual Scientific Meeting

Trends in Rates of ASIA Impairment Scale Conversion in Traumatic Complete Spinal Cord Injury