[The concept and measurement of functional disability in the elderly population: a literature review].

This article aims to review the main concepts and measures of functional disability currently used in studies focusing on this subject. According to this review, functional disability can be defined as a difficulty or the need for help for performing basic or more complex daily activities necessary for keeping an independent life in the community. As refers to measurement criteria, the studies do not follow a clear-cut standard, varying substantially in relation to scales, dimensions and classifications besides depending directly or indirectly on the kind of available information. A correct method for rating functional disability does not exist at yet. For this reason it is essential that the researchers clearly indicate the concept of functional disability used in the studies and detail, which measures or tools were applied.