Longitudinal course of behavioral problems during Alzheimer's disease: Linear versus curvilinear patterns of decline

Background. Patients with Alzheimer's Disease (AD) are commonly assumed to experience a linear decline in behavioral functioning that parallels progre ssive cognitive decline. However. some researchers have suggested that spec ific behavioral problems either decline at different rates or improve in la te dementia. Methods. The present analyses examined 150 AD patients at an initial assess ment. 61 of whom were also evaluated annually on two additional occasions. Measures of cognitive impairment and behavioral problems were obtained. Results. Cross-sectional results indicated curvilinear associations between dementia severity and certain behavioral problems (forgetful behaviors, an d emotional and impulsive behaviors). Longitudinal analyses further indicat ed trends for curvilinear rates of behavioral disturbance across time, with some problem areas showing improvement as AD progresses through the most s evere stages. Conclusions. Even though Alzheimer's disease is a progressive dementia char acterized by increasing cognitive deterioration, it appears to be inaccurat e to expect behavioral functioning to show the same linear decline across t ime.