Validation of the General Motor Function Assessment Scale - an instrument for the elderly

The purpose of this study was to test the General Motor Function Assessment Scale (GMF) for content and criterion validity in geriatric home-rehabilitation. Furthermore, the GMF was analysed with respect to sensitivity, distribution, and for floor and ceiling effects.

Content validity was explored by questionnaires circulated to ten experts in the field of geriatrics. Three assessment instruments were used to test 66 patients in home rehabilitation. In order to evaluate criterion validity GMF results were compared to results from the ADL-taxonomy test, and the Timed 'Up and Go' (TUG) test. GMF scores were analysed regarding, sensitivity, distribution and to check for floor or ceiling effects. Comparisons between pre-intervention assessments and post-intervention assessments were also made. Non-parametric statistics were used.

GMF covered and measured areas of relevance according to content validity. No floor effects in any of the subscales of GMF were seen. Comparison of pre-intervention and post-intervention assessments showed significant ceiling effects for all three subscales. As for criterion validity all subscales of GMF in terms of dependence, pain and insecurity correlated significantly with the activity parameter mobility of the ADL-taxonomy and TUG. GMF was sensitive enough to demonstrate changes between pre-intervention and post-intervention status.

GMF is a relevant instrument of assessment suitable for physiotherapists rehabilitating elderly in the home environment. For elderly with minor functional limitations the GMF shows ceiling effects.