Identification of passive personality changes may be a valuable clue in distinguishing early dementia with Lewy bodies from early Alzheimer’s disease, according to an article in the May 29 issue of Neurology. Dementia with Lewy bodies is the second most common neurodegenerative cause of dementia. It shares characteristics with both Alzheimer’s and Parkinson’s disease.

Determining the correct diagnosis is especially important because some medications used to treat the psychiatric symptoms of Alzheimer’s disease can be potentially dangerous for people with dementia with Lewy bodies.

American researchers evaluated 290 people who were part of a larger study and were tested every year for an average of about five years; by the end of the study, 128 adults had confirmed cases of dementia with Lewy bodies, 128 had Alzheimer’s disease, and 34 had no form of dementia. Researchers followed the participants through death, including autopsy results.

During annual interviews, participants or their family members were asked about changes in personality, interests and drives. Researchers found that even before diagnosis, people with dementia with Lewy bodies displayed passive personality changes, such as diminished emotional response, disinterest in hobbies, repetitive behaviors, and growing apathy, or lack of interest, more often than those with Alzheimer’s.

People with dementia with Lewy bodies were two times more likely to have passive personality traits at the time of first evaluation than people with Alzheimer’s disease. By the time of death, up to 75 percent of those with dementia with Lewy bodies had passive personality changes compared with 45 percent of those with Alzheimer’s disease.

“Currently we mainly look for memory problems and other cognitive problems to detect dementia, but personality changes can often occur several years before the cognitive problems,” said study author James E. Galvin, MD, MPH, of Washington University School of Medicine in St. Louis, MO.

“Identifying the earliest features of dementia may enable doctors to begin therapy as soon as possible. This will become increasingly important as newer, potentially disease-modifying medications are developed. It also gives the patient and family members more time to plan for the progressive decline.”

Galvin said more detailed personality tests are not often used in most office settings because of time and lack of training. “Our results show incorporating a brief, simple inventory of personality traits may help improve the detection of dementia with Lewy bodies,” said Galvin.