The cognitive decline scale of the psychogeriatric assessment scales (PAS): longitudinal data on its validity.
OBJECTIVE: The Cognitive Decline scale of the Psychogeriatric Assessment Scales (PAS)1 uses informant data to assess retrospectively change from earlier in life. Data from a 7-8-year longitudinal study were used to assess the validity of this scale against changes in cognitive performance and mortality. DESIGN AND MEASURES: PAS data were collected on three occasions, with gaps of 3.6 and 4.1 years between the waves. The Cognitive Decline score at Wave 3 was validated retrospectively against actual change on a brief test of current cognitive status (the PAS Cognitive Impairment scale) over the three waves, while the Cognitive Decline score at Wave 1 was assessed for predictive validity against future mortality and cognitive change. SETTING: A community survey in the Australian cities of Canberra and Queanbeyan. PARTICIPANTS: Participants were aged 70+ at the beginning of the study. The sample size varied from 729 to 279, depending on the number of waves involved. RESULTS: Participants with scores of 4+ on the Cognitive Decline scale at Wave 3 showed substantial deterioration over the previous 7-8 years. Scores of 4+ at Wave 1 predicted mortality and further cognitive deterioration. CONCLUSIONS: The Cognitive Decline scale allows a valid retrospective assessment of change and has predictive validity for subsequent cognitive deterioration and increased mortality.