Behavioral symptoms in mild cognitive impairment as compared with Alzheimer's disease and healthy older adults

Background: Mild cognitive impairment (MCI) is a clinical concept that categorizes subjects who are in an intermediate cognitive state between normal aging and dementia. The aim of this study is to characterize behavior in MCI compared with Alzheimer's disease (AD) and healthy older patients.

Design: A cross-sectional analysis of baseline data from a prospective, longitudinal study on behavioral symptoms of dementia and MCI was performed. The study population consisted of 270 MCI, 402 AD patients, and 108 healthy controls. Behavioral assessment was performed by means of Middelheim Frontality Score, Behavioral Pathology in Alzheimer's Disease Rating Scale, Cohen-Mansfield Agitation Inventory, and Cornell Scale for Depression in Dementia.

Results: Moderate-to-severe behavioral symptoms were present in 13% of MCI patients, as compared with 39% in AD patients and 3% in controls (p < 0.001). The general severity of behavioral symptoms was intermediate between controls and AD patients. The three most frequent symptoms in MCI patients were aggressiveness (49%), affective disturbance (45%), and anxiety (38%); in AD patients, the most frequent symptoms were aggressiveness (60%), activity disturbances (54%), and psychosis (40%). The prevalence and severity of frontal lobe symptoms, aggressiveness, activity disturbances, and delusions was intermediate between normal aging and AD. In addition, the severity of physically non-aggressive and verbally agitated behavior and the severity of depressive symptoms were also intermediate.

Conclusions: The behavioral profile of MCI patients is characterized as an intermediate state between normal aging and AD for the prevalence and severity of certain behavioral symptoms. Follow-up is ongoing to test the hypothesis that behavioral disturbances in MCI predict progression to dementia.