What is the definition of perceptions of decline? How to measure it?

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Perceptions of decline refer to individuals' beliefs or feelings that their abilities, health, or social conditions are deteriorating over time. This concept often encompasses cognitive, physical, and emotional aspects of aging.

To measure perceptions of decline, researchers typically use self-report questionnaires that assess individuals' attitudes toward aging and their perceived changes in functioning. Instruments like the Aging Perceptions Questionnaire (B-APQ) evaluate emotional reactions, expectations for positive and negative consequences, and feelings of control related to aging. Additionally, longitudinal studies may track changes in self-reported health and cognitive performance over time to correlate perceptions with actual outcomes.