The common language of Katz's index of ADL in six studies of aged and disabled patients.

Aged and disabled patients' need for coordinated services has increased the importance of a common language for their ability to perform the activities of daily living (ADL). This article aims at presenting Katz's Index of ADL and the use of it in six selected studies in order to show the availability for different purposes in divergent contexts. Katz's index is based on developmental principles and includes six common personal activities ordered into a cumulative scale. The use of the instrument provided both qualitative and quantitative information about disability among rather severely disabled patients in short-term and long-term hospital care, in nursing homes, in day-care and in home-care. The level of disability among the less disabled persons, who were independent in all of the six activities, were not differentiated by the index. A supplement of instrumental activities based on the same developmental principles is required, before a common language also for less disabled people can be established.