Comprehensive assessment for dementia: a necessity for differential diagnosis and management.

A fundamental purpose of comprehensive assessment is to identify impaired and spared abilities of the individual with Alzheimer's disease (AD). In the hands of a skilled professional, the results of a comprehensive assessment provide the basis for the design of meaningful care plans, document the need for appropriate services, and result in optimal patient care. To obtain valid test results, clinicians must be able to recognize and, when possible, control the influence of age-associated variables on test performance. Also, clinicians must be knowledgeable about the many purposes of assessment and consider them when selecting appropriate test instruments. Standardized tests are now available that have been designed specifically to assess communicative and cognitive function in persons with dementia of varying severity. In this article, four standardized tests are described, with particular focus on the information they provide about impaired and spared abilities. Measures that have been found to be useful in screening for the presence of dementia also are discussed.