Life-Space Assessment and Physical Activity Scale for the Elderly: Validity of Proxy Informant Responses

Abstract Objective To validate the administration of the Life-Space Assessment (LSA) and Physical Activity Scale for the Elderly (PASE) surveys to proxy informants, as would be necessary when measuring long-term outcomes in acutely ill, hospitalized older adults who are initially incapacitated but eventually return to the community. Design Cross-sectional study. Setting General community. Participants Convenience sample of dyads (N=40) composed of an ambulatory older adult and a familiar companion. Interventions Dyads completed the LSA and PASE surveys on 1 occasion. Companions based their responses on the recent mobility and physical activity of the older adult. Main Outcome Measures Paired total scores for each instrument. Results At a group level, the difference between older adult and companion mean scores for each instrument was not significant ( P >.05). Standardized mean difference values were small ( d .05). At an individual level, older adults and companions agreed more closely on the LSA than on the PASE. However, disagreement in excess of estimated measurement error occurred in 40% of the dyads for the LSA and in none of the dyads for the PASE. Conclusions Older adults and companions collectively provided similar responses on each instrument. Nonetheless, varying levels of agreement within individual dyads suggested that proxy responses should be considered carefully. Implications for clinical research and practice research are discussed.