Measuring quality of life: Comparing family members' and friends' ratings with those of their aphasic partners

Abstract

Background: A greater awareness of the social consequences of impairments and a growing need for patient-centred outcomes in contemporary health care has made it increasingly important for clinicians to gather information on clients' quality of life (QoL). As QoL measures typically require respondents to perform a number of complex language and cognitive processes, there is a valid concern as to whether clients with aphasia can reliably self-report. In this situation, significant others and healthcare providers are called upon to make judgements as proxy respondents. Evidence from medical and chronic disability and health literature suggests that the responses of proxies may be interchangeable with those of patients, however it is not known whether the same is true for language-impaired respondents. Aims: The current research compared scores from aphasic and proxy respondents to investigate whether proxy respondents could be used to obtain reliable information on aphasic people's QoL. Reliable information was considered as statistically similar group comparisons with small effect sizes, and moderate to good agreement between aphasic and proxy respondents' scores. Methods & Procedures: A total of 30 aphasic respondents aged 57 to 88 years, and 30 proxy respondents (primarily spouses and children) aged 27 to 82 years were interviewed separately by a speech and language therapist using four QoL measures: a global rating, the Short Form 36 Health Survey, the Dartmouth COOP Charts, and the How I Feel About Myself well-being scale. A systematic cueing procedure was used to facilitate respondents' understanding. Subscale scores were compared for group differences using paired samples t tests and effect size calculations, and individually for agreement using intraclass correlations. Outcomes & Results: Proxy respondents demonstrated a significant systematic negative bias in rating their aphasic partners' global QoL, physical functioning, general or overall health, pain, and vitality. Conversely, proxy respondents rated statistically the same as their aphasic partners on physical fitness, feelings, daily activities, quality of life (COOP), total well-being, autonomy, environmental mastery, and purpose in life, with at least moderate agreement. Similar to other literature, there was generally higher agreement for objective domains than subjective domains, and greater agreement on the SF-36 than the global rating measure, the COOP Charts, or the well-being scale. Conclusions: Family members and friends of people with aphasia cannot be interchangeably accepted as reliable informants of their partners' QoL. They rated their partners significantly lower in global and physical health-related QoL, and yet their systematic behaviours in ratings could be useful for clinicians and researchers as their aphasic partners' scores can be easily and confidently predicted. Conversely, they appeared to be reliable informants in other areas, namely feelings, daily activities, and well-being, as well as overall quality of life (when using the illustrated COOP QoL measure), however further research is needed to clarify statistical definitions and interpretations of reliability. Finally, there was no relationship between proxies' and aphasic partners' ratings of social health (functioning, activities, support, relations with others) and self-acceptance. Researchers and clinicians need to be aware of these biases when soliciting information from significant others, and further research is needed to develop QoL measures that are accessible for people with aphasia.