Predicting Aberrant Behavior in Alzheimer's Disease

UMMS Affiliation

Department of Neurology; Department of Psychiatry

Publication Date


Document Type



Alzheimer Disease


Neurology | Neuroscience and Neurobiology


Purpose: To investigate the factors that predict the development or predispose to the occurrence of behavioral disturbances that occur frequently in Alzheimer's disease (AD).

Materials and Methods: The factors examined at entry into the study included individual distinguishing features (e.g., premorbid personality), disease characteristics (e.g., functional competence in activities of daily living), and care and living situation (e.g., type of caregiver). The subsequent occurrence of seven aberrant behaviors was assessed over a mean of 17.83 months. Life table statistical methods were used to determine the relative importance of the factors in predicting behavioral disturbances. The study took place at the Alzheimer's Disease Research Center at the University of Massachusetts Medical Center in Worcester, Massachusetts, with 30 mildly to moderately affected community-dwelling AD patients and their caregivers. Aggressive behaviors (physical and verbal attacks), disordered ideation (hallucinations, paranoia, delusions), and mechanical/motor abnormalities (wandering, hyperkinesia) were assessed using the Caretaker Obstreperous Behavior Rating Assessment (COBRA) Scale (1).

Results: Univariate Kaplan-Meier life table analyses suggested that greater disease severity and younger age of disease onset predicted the development of disordered ideation. Greater disease severity remained the best predictor of disordered ideation in the multivariate Cox proportional hazards model. Neither premorbid personality or caregiver characteristics predicted the development of aberrant behaviors. Post hoc analyses suggested that patients who exhibited aggressive behaviors on initial evaluation were remembered as having been more hostile premorbidly than those patients who developed aggressive behaviors later in follow-up.

>strong>Conclusion: The results from this study suggest that greater disease severity is a significant risk factor for the development of troublesome and disruptive behaviors. Premorbid personality traits do not predispose to subsequent behavioral disturbances in AD. Rather, the memories of caregivers appear to be biased by the patients' current behavioral repertoire. Replication of these results is needed in a larger sample of patients to strengthen the conclusions from this study.

(C) Lippincott-Raven Publishers.


Neuropsychiatry, Neuropsychology, and Behavioral Neurology, 9:162-170. Link to article on publisher's website

Journal/Book/Conference Title

Neuropsychiatry, Neuropsychology, and Behavioral Neurology

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