Behavioral disturbances of dementia: an overview of phenomenology and methodologic concerns.

Behavioral disturbances in dementia are some of the most burden-some features with which the caregivers must cope. These symptoms are particularly important because they are likely to be responsive to both pharmacological and nonpharmacological intervention strategies. Before the 1980s, rating scales for patients suffering from dementia did not separate cognitive features from noncognitive behavioral symptoms. This was a major problem because the evolution and course of behavioral symptoms in dementias, such as Alzheimer's disease, is different from the evolution and course of cognitive and cognition-related symptomatology. Before appropriate rating scales could be developed for the assessment of behavioral disturbances in dementia, the specific nature of these disturbances had to be described in the medical literature. Publications in the late 1980s described the specific behavioral disturbances occurring in dementia patients in detail for the first time. The rating scales that have been developed from these studies are as reliable as cognitive assessment measures. Instruments are now available that are based on information provided by the caregiver or that are based on observation of the patient made by the clinician. Construct validity, reliability, and the differences in methodology of these scales are compared in this overview. Using these scales will enable clinicians to assess pharmacological and nonpharmacological intervention strategies for behavioral symptoms in dementia with enhanced sensitivity.