LAS VEGAS – Hallucinations are a significant predictor of functional impairment in patients with Alzheimer's disease, Wing Yee Mok, M.D., said at the annual meeting of the American Geriatrics Society.
In a retrospective analysis of 100 patients at a mean age of 80 years and with a mean 3 years of education, the presence of hallucinations, as well as a low score on the Mini-Mental State Examination (MMSE), were independent predictors of problems in activities of daily living, said Dr. Mok, a resident in the department of medicine at Queen Mary Hospital in Hong Kong.
Cognitive impairment is known to affect functional capacity, but the impact of noncognitive symptoms, such as hallucinations, has not been studied as extensively, she said.
The patients were recruited from the memory clinic at Queen Mary Hospital. They underwent a series of tests to assess various aspects of their cognitive and functional abilities, including the MMSE, the Barthel Index of Activities of Daily Living (BADL), and Lawton's Instrumental Activities of Daily Living (IADL). They were also examined for noncognitive psychiatric symptoms, including hallucinations, delusions, anxiety, euphoria, and apathy.
The BADL measures the patient's ability to perform basic daily activities, such as bathing, eating, and grooming without assistance. Scores range from 0, suggesting complete incapacitation, to 20, complete independence. The patients in this study had a mean score of 18.4.
The IADL assesses the patient's ability to perform tasks that require some planning and abstraction, such as doing laundry, shopping for groceries, and managing money. Scores range from 0, suggesting inability to perform the task at all, to 8, meaning no help is needed with any of the activities. These patients had a mean score of 5.9.
The MMSE measures cognitive function by asking patients the date and place, having them name various objects, remember words, and subtract a series of numbers. Scores vary depending on the patient's age and level of education, but mean scores for unimpaired 80-year-olds range from 20, for those with up to a fourth-grade education, to 27, for those with a college degree. The mean MMSE score for these patients was 15.1.
In a multiple linear regression analysis, the presence of hallucinations was a significant independent predictor of impairment as measured by the IADL but not the BADL. A low score on the MMSE correlated strongly with low scores on the BADL and the IADL and was another independent predictor of poor functional status.
Screening for and managing hallucinations could improve functional status in this patient population, Dr. Mok said.