Measuring global functioning in older adults with cognitive impairments using the Rasch model.

The Rasch model was able to combine cognitive and functional measures into a single score (global functioning score). All together, these results suggest that the diverse cognitive and functional measures can be considered part of one single dimension (global functioning) and that this dimension can be measured as a single construct and score. This study offers an alternative perspective for future development of instruments that would help clinicians in measuring global functioning in older adults' patients at different stages of cognitive impairments and different baseline level of performance.