Evaluation of the demented patient.

An adequate history from the patient and a family member, an examination for signs and symptoms suggestive of contributing organic disease, plus an individualized diagnostic battery of laboratory tests are sufficient workup for most patients presenting with the dementia syndrome. Electroencephalography, computerized axial tomographic scanning, or psychometric testing are not usually required. The results of eight studies investigating demented individuals are reviewed. Across these studies, 56 percent of cases were attributable to primary dementia, 15 percent were secondary to reversible causes, 13 percent were secondary to irreversible conditions, and 15 percent of individuals had been wrongly labeled demented. Of reversible dementias including depression, 56 percent of patients improved with therapy. Metabolic disorders were associated with about 25 percent of reversible dementias and accounted for less than 5 percent of all patients investigated for the dementia syndrome.