The immediate clinical significance of Confusion Assessment Method (CAM)-defined core symptoms of delirium not meeting criteria for delirium is unclear. This study proposed to determine if such symptoms are associated with cognitive and functional impairment, mood and behavior problems and increased Burden of Care (BOC) in older long-term care (LTC) residents.

The study was a secondary analysis of data collected for a prospective cohort study of delirium. Two hundred and fifty-eight LTC residents aged 65 years and older in seven LTC facilities had monthly assessments (for up to six months) of CAM – defined core symptoms of delirium (fluctuation, inattention, disorganized thinking, and altered level of consciousness) and five outcome measures: Mini-Mental State Exam, Barthel Index, Cornell Scale for Depression, Nursing Home Behavioral Problems Scale, and Burden of Care. Associations between core symptoms and the five outcome measures were analyzed using generalized estimating equations.

Core symptoms of delirium not meeting criteria for delirium among residents with and without dementia were associated with cognitive and functional impairment and mood and behavior problems but not increased BOC. The associations appear to be intermediate between those of full delirium and no core symptoms and were greater for residents with than without dementia.

CAM-defined core symptoms of delirium not meeting criteria for delirium appear to be associated with cognitive and functional impairment and mood and behavior problems in LTC residents with or without dementia. These findings may have implications for the prevention and management of such impairments and problems in LTC settings.