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) 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.