ADCS Prevention Instrument Project: Behavioral measures in primary prevention trials

Background: There is an urgent need for the development of inexpensive, reliable, and valid instruments that can be used in large-scale primary prevention trials of compounds aimed at ameliorating progression from normal aging to mild cognitive impairment or Alzheimer disease. The Alzheimer's Disease Cooperative Study launched a Prevention Instrument Project to develop such methodologies. Behavioral changes are common in diseases causing dementia and may occur prior to a point when cognitive changes are sufficiently severe to allow diagnosis of a dementia syndrome. Experimental behavioral measures were included in the protocol to examine this hypothesis. Methods: Six hundred forty-four individuals with CDR 0 or 0.5 were randomly assigned to receive a brief in-clinic behavioral assessment or telephonic administration of the same assessment. The questions were asked to the individual and their research partner. The Prevention instrument Project included behavioral measures of depression, anxiety, irritability, and apathy. Results: All measures demonstrated acceptable test-retest reliability at 3-month intervals except for the single-item depression screen by the subjects' research partner. Behavioral changes are significantly more common among patients with Clinical Dementia Rating (CDR) scores of 0.5 compared with CDR scores of 0. Behavioral alterations including irritability, anxiety, and apathy are more common among ethnic minorities than among the White population. Depression, irritability, anxiety, and apathy are significantly correlated with each other. Conclusions: Behavioral changes are common among those with mild degrees of cognitive compromise (CDR 0.5). Telephonic assessment of behavioral changes is feasible. The predictive value of these alterations for progression to Alzheimer disease or other dementias will be assessed longitudinally.