Severity of upper and lower extremity functional limitation: Scale development and validation with self-report and performance-based measures of physical function

Objectives. To better understand disablement and transitions from impairmen t to disability, discrete valid measures of functional limitation are neede d. This study reports the development and criterion-related validity of sca les that quantify severity of upper and lower extremity functional limitati on. Methods. Data are from 3,635 cognitively intact community-dwelling women ag ed 65 years and older and 1,002 moderately to severely disabled participant s in the Women's Health and Aging Study. Scales assessing severity of upper and lower extremity functional limitation were constructed from commonly a vailable questions on functional difficulty. Criterion-related validity was evaluated with self-report and performance-based measures. Results. The upper and lower extremity scales range from 0 to 6 and 0 to 9, respectively. Scale scores were well distributed in the disabled group and discriminated limitations in the broader community. For both scales, rates of difficulty for all ADL and IADL increased (p < .001) with increasing se verity score, and percent able and mean performance on respective upper and lower extremity tasks decreased (p < .01). Discussion. These scales, constructed from commonly used self-report measur es of function, provide discrete measures of upper and lower functional lim itation. Because these scales are distinct from measures of disability and impairment, their use should facilitate increased understanding of the disa blement process.