Assessment of Impairment in Patients with Acute Traumatic Spinal Cord Injury: A Systematic Review of the Literature

The most common primary end-point of the trial on treatment of traumatic spinal cord injury (SCI) is the degree of impairment. The American Spinal Injury Association (ASIA) Standards have been widely used to assess motor function and pin-prick and light-touch sensory function. In addition, pain assessment is another clinically relevant aspect of the impairment in individuals with SCI. Given this, we sought to systematically review the studies that focused on the psychometric properties of ASIA Standards and all previously used outcome measures of pain in the SCI population in the acute care setting. For the primary literature search strategy, the MEDLINE, CINAHL, EMBASE, and Cochrane databases were sought out. Subsequently, a secondary search strategy was carried out using the articles listed in the references of meta-analysis, systematic, and non-systematic review articles. Two reviewers (JCF and VN) independently selected the articles that fulfill the inclusion and exclusion, assessed the level of evidence of each article, and appraised the psychometric properties of each instrument. Divergences during those steps were solved by consensus between both reviewers. Of 400 abstracts captured in our primary search strategy on the ASIA Standards, 16 full articles fulfilled the inclusion and exclusion criteria. An additional 40 references were obtained from two prior systematic reviews on ASIA Standards. While 45 of 56 of the studies on ASIA Standards provided level 4 evidence, there were 11 level 2b evidence studies. Convergent construct validity (n = 34), reliability (n = 12), and responsiveness (n = 10) were the most commonly studied psychometric properties of the ASIA Standards, but two prior studies examined their content validity. Of the 267 abstracts yielded in our primary search on pain assessment, 24 articles with level 4 evidence fulfilled the inclusion and exclusion criteria. There was no study that examined pain assessment in the acute care setting. While 18 of 24 articles studied an instrument for assessment of pain intensity, the remaining six studies were focused on classifications of pain in the SCI population. In conclusion, the ASIA Standards represent an appropriate instrument to categorize and evaluate spinal cord injured adults over time with respect to their motor and sensory function. Nevertheless, further investigation of the psychometric properties of the ASIA Standards is recommended due to a lack of studies focused on some key elements of responsiveness, including minimal clinically important difference. The visual analog scale (VAS) is the most commonly studied instrument of assessment of pain intensity in the SCI population. However, further investigation is required with regard to its reliability and responsiveness in the SCI population. Our results also suggest that there is no instrument with appropriate psychometric properties for this particular population.