Functional independence staging: conceptual foundation, face validity, and empirical derivation

To develop a staging system for functional independence across the activities of daily living (ADLs), sphincter-management, mobility, and executive-function domains (ASME) for the FIM instrument that is consistent with the International Classification of Functioning, Disability and Health.

National data were used to define the stages. We searched for the most likely configurations of item scores that increased ability to perform component activities in each domain by approximately 1 level per item per stage.

Inpatient rehabilitation facilities.

Data from 218,290 people discharged from 560 US inpatient rehabilitation facilities in 1995.

Not applicable.

Activity profiles formed from FIM scores.

Seven stages were defined separately for each ASME domain. Stages approximate the average amount of effort expended by the patient when performing the component activities included in a domain, beginning with less than 25% of effort at the lowest total assistance (stage 1) and ending with 100% effort at the highest complete independence (stage 7). Consistent with developmental principles, independence is achieved at lower stages in the most fundamental activities of eating, transfers, and communication. Recovery of independence in the more difficult activities of bathing, stair climbing, and problem solving does not occur until the higher stages are reached. The degree of independence is described with a shorthand abbreviation of the domains followed by the stage the patient has reached in each domain. For example, ASME 5,1,6,7 indicates need for supervision in the ADLs (A-5), total assistance in sphincter management (S-1), modified independence in mobility (M-6), and complete independence in executive functions (E-7).

ASME stages serve as a common language and shorthand for expressing the functional consequences of illness and injury, while complementing information about impairment and diagnosis, thereby facilitating communication, assessment, and goal setting in terms that are meaningful to patients and their care givers.