Cognitive ability and functional status

Significant confusion exists in the literature about functional status. Des pite its importance, little attention has focused on developing and substan tiating frameworks that detail the underpinnings of functional status, whic h has resulted in lack of agreement about its definition and dimensions. Th e purpose of this literature review was to examine the development of funct ional status and to describe the inclusion of its cognitive dimension. Cogn ition is one key dimension of functional status. One must 'know how' to per form to be successful in an activity. While cognitive capacity is generally considered in relation to functional status, the nature of the cognitive d imension is poorly described and poorly understood. Three databases were se lected for review: Citations in Nursing and Allied Health (CINAHL), Psychol ogy Literature (PsychLit), and the Medical data base known as MedLine. Key word searches identified thousands of sources. This analysis includes an ex tensive sampling of these sources from the 1960s through to 1998. The sourc es sorted into four primary categories and demonstrate a growing recognitio n of the cognitive dimension of functional status in the literature. Despit e this recognition, the lack of conceptual clarity of both the term functio nal status and its cognitive dimension limits communication among disciplin es and limits comparisons of functional status outcomes across studies. Fun ctional status models are needed that include cognition as a core dimension . Population specific descriptions of the cognitive dimension should be gui ded by knowledge in the neurosciences.