Background: Self-report quality of life (QoL) measures for people with dementia are widely used as outcome measures in trials of dementia care interventions. Depressed mood, relationship quality and neuropsychiatric symptoms predict scores on these measures, whereas cognitive impairment and functional abilities typically do not. This study examines whether these self-reports are influenced by personality and by the person's awareness of his/her impairments. A strong negative association between QoL and awareness of deficits would have implications for the validity of self-report in this context and for therapeutic interventions aiming to increase adjustment and coping.
Methods: Participants were 101 individuals with early‒stage dementia and their family carers participating in the Memory Impairment and Dementia Awareness (MIDAS) Study. QoL was assessed using the QoL-AD scale, and awareness was assessed in relation to memory, activities of daily living and social functioning. Self-concept, conscientiousness, quality of relationship and mood were assessed and a brief neuropsychological battery administered. Carers rated their own stress and well-being and reported on neuropsychiatric symptoms. A series of regression analyses predicting QoL-AD were carried out, identifying key variables in each domain of assessment to take forward to an overall model.
Results: Cognitive impairment was not related to QoL. The final model accounted for 57% of the variance in QoL-AD scores, with significant contributions from depressed mood, severity of irritability shown by the person with dementia, self-concept, quality of relationship (rated by the person with dementia) and male gender. The bivariate relationships of QoL-AD with awareness of memory function, awareness of functional abilities and conscientiousness were mediated by both depressed mood and self-concept.
Conclusions: This study reports the most comprehensive approach to evaluation of awareness to date. Most of the indices of awareness used are not related to self-reported QoL. Discrepancies in evaluative judgements of memory function and functional abilities between people with dementia and carers are related to QoL, but this relationship is mediated by both depressed mood and self-concept, which have a much stronger relationship with QoL. The validity of self-report measures of QoL in people with early stage dementia is supported by these results.