Laboratory and Brain Imaging Studies for Dementia May Not Be Helpful

Author: Wendy L. Adams
Date: March 15, 2001

(North American Primary Care Research Group) Laboratory and brain imaging studies detect potentially reversible causes of dementia in only about 1 percent of patients presenting for geriatric assessment, and, therefore, contribute little to the diagnosis. This is the conclusion of a retrospective chart review of all 1,034 patients who presented for geriatric assessment to the University of Nebraska Medical Center, Omaha, between 1991 and 1998. The mean age of the patients was 78.4 years (age range: 49 to 100) and 70.3 percent were female. Of the 1,001 patients who received Clinical Dementia Rating Scale scores, 914 (91.3 percent) scored above 0, indicating probable or definite dementia, and the mean Mini-Mental State Examination (MMSE) score was 20.2 [+ or -] 6.0. For most laboratory studies, patients with dementia had fewer abnormal results than patients without dementia: thyrotropin-stimulating hormone (18.3 percent versus 24.4 percent, respectively); vitamin B12 (11.4 percent versus 16.7 percent, respectively); sodium (5.5 percent versus 4.9 percent, respectively); creatinine (22.8 percent versus 28.8 percent, respectively); and calcium (2.4 percent versus 1.2 percent, respectively). In no patients was an abnormal laboratory value the primary cause of the dementia. Brain imaging was conducted in 914 patients, and potentially reversible conditions that were detected included normal pressure hydrocephalus (1 percent of patients) and brain tumor (0.3 percent of patients).--WENDY L. ADAMS, M.D., M.P.H., ET AL., University Of Nebraska Medical Center, Omaha, Nebraska.

COPYRIGHT 2001 American Academy of Family PhysiciansCOPYRIGHT 2001 Gale Group

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