Development and Validation of Crosswalks Between FIM® and SCIM III for Voluntary Musculoskeletal Movement Functions

Neurorehabil Neural Repair, 2021 · DOI: 10.1177/15459683211033854 · Published: October 1, 2021

Spinal Cord Injury Rehabilitation Research Methodology & Design

Simple Explanation

The study addresses the problem that data from different spinal cord injury (SCI) databases cannot be easily compared because they use different methods to measure functional recovery. The researchers aimed to create a 'crosswalk' that allows converting scores between the Functional Independence Measure (FIM®) and the Spinal Cord Independence Measure III (SCIM III), two common tools for assessing functional ability in SCI patients. They used three different methods (expert panel, equipercentile, and Rasch analysis) to build this crosswalk and then tested how well it worked using data from Switzerland, the US, and Canada.

Study Duration

Not specified

Participants

Swiss dataset, n = 662; US dataset, n = 119; and Canadian datasets, n = 133

Evidence Level

Not specified

Key Findings

1
All three methods for creating the crosswalk (expert panel, equipercentile, and Rasch analysis) resulted in strong correlations between the original scores and the converted scores.
2
The equipercentile and Rasch methods appeared to produce the strongest crosswalks based on secondary criteria, suggesting they are more accurate.
3
The Rasch FIM®/SCIM III crosswalk is recommended because it is based on co-calibration of linearized measures, allowing for more sophisticated parametric analyses.

Research Summary

The study developed and validated crosswalks between the FIM® and SCIM III for voluntary musculoskeletal movement items in SCI patients using retrospective datasets from Switzerland, the US, and Canada. Three methods (expert panel, equipercentile, and Rasch analysis) were employed to create the crosswalks, and their strength was assessed primarily by the correlation between observed and crosswalked scores. The Rasch analysis-based crosswalk is recommended due to its co-calibration of linearized measures, enabling more sophisticated parametric analyses and facilitating comparisons of functional recovery across international databases.

Practical Implications

Data Harmonization

The crosswalk enables the comparison and pooling of data from different SCI databases that use either FIM® or SCIM III, facilitating meta-analyses and advanced statistical approaches.

Clinical Trials

The crosswalk allows for larger and more diverse international datasets in clinical trials, which can help identify impactful outcomes that exceed natural recovery.

International Comparisons

Researchers can compare functional outcomes across different countries or systems of care, even when different outcome measures (FIM® or SCIM III) are used.

Study Limitations

1
The study included a sample with considerable missing demographic data, which limited its analysis of subpopulation invariance.
2
FIM® and SCIM III scores collected within 7 days of one another were used to develop and validate the crosswalks, a closer time point may have resulted in even stronger crosswalks.
3
The crosswalk developed in this study only includes items reflecting voluntary musculoskeletal function and can only be applied to this dimension.

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