Functional ability level development and validation: providing clinical meaning for Spinal Cord Injury Functional Index scores

Objectives: To develop functional ability levels for the Spinal Cord Injury Functional Index (SCI-FI) and to validate them using calibration and reliability samples.

Design: Three-phase strategy involved (1) performing quantitative synthesis of SCI-FI data to create item maps; (2) using a panel of experts to identify functional ability levels after the bookmarking and Delphi consensus-building process; and (3) performing quantitative analyses to examine demographic characteristics across 2 samples, assessing the distribution pattern across functional ability levels, and examining concurrent validity using the self-reported functional measure and the observer-rated FIM.

Setting: Inpatient and community settings.

Participants: People 18 years or older with traumatic spinal cord injury (N=1124) were recruited from the Spinal Cord Injury Model Systems programs and stratified by diagnosis, severity, and time since injury (n=855 and n=269 for calibration and reliability samples, respectively).

Interventions: Not applicable.

Main outcome measure: SCI-FI.

Results: Five functional ability levels were identified for all SCI-FI domains, except fine motor having 4 functional ability levels. Statistical test results indicated no significant differences in the distribution pattern across the 2 samples across functional ability levels for all domains except for ambulation. Known-group comparisons were able to discern the spinal cord injury population as expected. Basic mobility, self-care, and wheelchair mobility domains had a cluster of persons with paraplegia and incomplete lesions at higher functional ability levels and persons with tetraplegia and complete lesions at lower functional ability levels. For the ambulation domain, the distribution was skewed to the lower end, with a relatively small percentage of persons with incomplete lesions (paraplegia and tetraplegia) at higher functional ability levels. For the fine motor domain, the distribution was skewed to higher functional ability levels, with a high percentage of persons with paraplegia at the highest level (complete and incomplete lesions). Concurrent validity analyses revealed SCI-FI functional levels to be significantly (P<.001) positively correlated with both the self-reported functional measure and the observer-rated FIM.

Conclusions: Clinicians can use functional ability levels to discuss patients' functional capabilities with them and their family.