Alzheimer's Drug Shows Promise For Treating Another Type of Dementia

A new study suggests that a treatment for Alzheimer's, the most common type of dementia, can also treat the second most common type – dementia with Lewy bodies (DLB).

The treatment is a cholinesterase inhibitor (ChEI): it's already been used with DLB patients, but up until now it was unclear how effective it was. This new research indicates it can indeed slow cognitive decline.

DLB is closely related to Alzheimer's and Parkinson's, but we know less about it. The team from the Karolinska Institutet in Sweden says their findings add some important depth to our understanding of the condition.

"Our results highlight the potential benefits of ChEIs for patients with DLB and support updating treatment guidelines," says neurobiologist Maria Eriksdotter.

The study involved 1,095 people with DLB, who were being treated with a ChEI or memantine (another Alzheimer's treatment), or not being given either of the medications. The study participants were followed for a period of up to 10 years.

Those on ChEIs – particularly two types called donepezil and galantamine – showed significantly slower cognitive decline than those being given memantine or neither treatment. There was also a reduced risk of death in the CHEI group, though this only held for the first year after DLB diagnosis.

While this was an observational study of existing records rather than a clinical trial, and therefore can't show cause and effect, it does indicate that it's worth continuing to investigate ChEIs as effective treatments for some DLB patients.

Around 10–15 percent of dementia cases are caused by DLB, which typically drives faster cognitive and functional decline than Alzheimer's, affecting sleep, behavior, cognition, movement, and bodily functions.

"This study demonstrates that the use of ChEIs in patients with DLB may reduce the risk of cognitive decline compared to memantine treatment or no treatment," write the researchers in their published paper.

"Future studies are needed to better elucidate these mechanisms."

In this sample at least, ChEIs made more of a difference than memantine. Neither treatment reduced the risk of major adverse cardiovascular events, which was somewhat surprising as ChEIs have shown to reduce risk in Alzheimer's patients.

The main job of ChEIs is to slow down the loss of the chemical acetylcholine; it's made by neurons, is crucial for processing information in the brain, and gradually gets lost as Alzheimer's takes hold. It seems that this slowing down is beneficial for brains with DLB too, something further research can look into.

"There are currently no approved treatments for DLB, so doctors often use drugs for Alzheimer's disease, such as cholinesterase inhibitors and memantine, for symptom relief," says neurobiologist Hong Xu, from the Karolinska Institutet.

"However, the effectiveness of these treatments remains uncertain due to inconsistent trial results and limited long-term data."

The research has been published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.