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Valley Psychiatry Article

Executive Deficits As A Predictor Of Behavioral Disturbance In Dementia

Behavioral and psychological symptoms of dementia are non-cognitive manifestations common to all forms of dementia. These include depression, anxiety, and psychosis. When prolonged or severe these symptoms cause anguish for both caregivers and patients. Executive dysfunction, described below contributes to these problematic symptoms. Behavioral disturbance is one of the most difficult of these symptoms to manage. The result is often early long term care placement and aggressive medication management.

Early detection of patients at risk for developing subsequent behavioral disturbance in the course of their dementia benefits both patient and caregivers. The clinician is able provide more accurate prognosis and identify these at risk patients who require more intensive follow-up and support.

A study in the February 2008 American Journal of Geriatric Psychiatry investigated early impairments of executive functions as possible predictors for disturbed behavior during later stages of dementia. Disturbances of executive functioning are typical across the various types of dementia including Alzheimer’s and vascular dementia. It is often seen early in the course of dementia, frequently before significant memory deficits are apparent.

Executive functions are higher order-cognitive abilities that control and regulate simpler functions, such as attention and motor skills, into complex goal-directed behaviors. These goal-directed behaviors include the ability to think abstractly, problems solve, and control one’s behavior appropriately. Impairments in executive functioning result in disinhibition, cognitive inflexibility, apathy, and lack of initiative.

The authors of this study compared early global cognitive functioning tests versus early measures of executive functioning in their ability to predict future behavioral disturbance. They looked at two baseline cognitive measurements, the Mini-Mental Status Exam and the Cambridge Examination for Mental Disorders of the Elderly-Revised. Neither of these purely cognitive tests was predictive of later behavioral disturbance as measured with the Neuropsychiatric Inventory, the Cohen Mansfield Agitation Inventory, and the Dementia Apathy Interview at follow-up between three and six years later.

In contrast, a measure of executive dysfunction at baseline, the Cambridge Examination for Mental Disorders of the Elderly with an executive function battery, did predict future behavioral disturbance. Higher degrees of executive dysfunction at baseline predicted higher levels of behavioral disturbance later in the course of dementia.

Apathy, one component of the initial executive functioning battery, had the highest correlation with future behavioral disturbance. Apathy is characterized by the loss of initiation and motivation to participate in activities, social withdrawal, and emotional indifference. It occurs following damage to frontal lobes.

More study is necessary because this study had a low number of participants and the measures were collected as part of a clinical assessment and not a formal research project.

Yet this study implies that early executive dysfunction is an important cause of later social and behavioral deficits resulting in significant patient and caregiver distress. Detecting early executive impairment should be included in early dementia evaluations. An awareness of the level of early executive impairment helps the clinician target patients that need more follow-up and support.

Another implication of this study is the promise of dementia medications (acetylcholinesterase inhibitors such as Aricept and NMDA glutamate blockers such as Namenda) used prophylactically in this population with significant executive functioning at baseline. These medications slow the progression of dementia. Using these agents should in theory prevent or lessen the need for later use of antipsychotic or mood stabilizing medications, with their associated higher side effect burden, to control behavioral disturbance.

Valley Psychiatry Article