Alzheimer's disease (AD) and vascular dementia (VaD) have much more in common than current diagnostic guidelines allow, according to researchers at the Drexel University College of Medicine. Their study is set for publication in the September edition of the Journal of Alzheimer's Disease.
“Through this study, we were able to determine that these two common forms of dementia are not wholly separate,” David J. Libon, PhD, the study's lead investigator and a professor in the Drexel Department of Neurology, said in a press release. “These shared characteristics should be taken into consideration both in the development of future AD and VaD diagnostic guidelines and in selecting patients for newly emerging medicine designed to treat dementia.”
The researchers analyzed 223 people who have dementia and were seen at an outpatient memory clinic and in whom AD or VaD was diagnosed. Participants were evaluated by a team of dementia specialists and underwent neuropsychologic testing, brain scans and blood tests.
People with dementia thought to have either AD or VaD could be sorted into distinct, very nuanced clinical profiles, the researchers found. Using latent class analysis, they were able to identify four distinct groups: those with moderate/mixed dementia, those with mild/mixed dementia, a dysexecutive group with significant impairment in multitasking and an amnestic group with profound memory loss.
Follow-up analyses comparing these four groups on neuropsychologic measures that delved deeper into the process and errors produced on neuropsychologic tests showed that those in the dysexecutive group exhibited marked difficulty sustaining attention and concentration. Those in the moderate/mixed group evidenced pronounced and greater impairment on language-related tests compared with other neuropsychologic abilities. Those in the amnestic group were clearly distinguished by severe memory problems but showed less impairment on other neuropsychologic tests. Those in the mild/mixed group exhibited milder memory deficits that were intermediary between the amnestic and moderate/mixed groups.
Researchers from Temple University; the University of Florida; the University of California, San Diego; the VA San Diego Healthcare System; the University of Illinois; the University of Southern California; Boston University; the Framingham Heart Study; and the North Dakota Medical School also participated in the study.