Techniques for measurement and assessment of mobility in rehabilitation: a theoretical approach

Objective: Mobility is an important construct in rehabilitation; many instruments have emerged which measure or assess (aspects of) mobility. In the selection or development of an appropriate technique, knowledge about the fundamentals of rehabilitation medicine is needed, as well as about essential characteristics of techniques and fundamental differences between them. The aim of this paper is to classify, assess and discuss current techniques which are or can be used to measure aspects of mobility. Design: Eight techniques (physical science techniques, clinimetry, observation, diaries, questionnaires, actigraphy, physiological techniques and activity monitors) are classified, assessed and discussed, based on the level of outcome measures, the aspect of mobility they measure, and methodological and practical criteria. Results and conclusions: Rehabilitation medicine has a particular need for instruments that enable measurement of outcome measures on the level of activity and role fulfilment. Techniques differ in the type and number of mobility aspects they measure. Furthermore, important differences exist based on methodological and practical criteria. One optimal technique does not exist: the choice of a technique always depends on a complexity of factors, such as clinical problem, research questions, the mobility aspect of interest, required methodological strength, costs and availability.