Parkinson’s disease dementia: a neural networks perspective

Great review from colleagues at the Institute of Neurology. This is treated as a somewhat taboo subject, with patients and relatives often unaware of the possibility (perhaps even probability) of PD dementia with long-term disease. One issue is the lack of really good treatments for it, which perhaps means that people don't want to discuss it. This review discusses some of the reasons why treatment is currently sub-optimal but suggests positive routes forward including novel targets for deep brain stimulation... the trials are already underway!

James Gratwicke , Marjan Jahanshahi , Thomas Foltynie
Brain 2015 First published online: 17 April 2015
DOI: http://dx.doi.org/10.1093/brain/awv104 

In the long-term, with progression of the illness, Parkinson’s disease dementia affects up to 90% of patients with Parkinson’s disease. With increasing life expectancy in western countries, Parkinson’s disease dementia is set to become even more prevalent in the future. However, current treatments only give modest symptomatic benefit at best. New treatments are slow in development because unlike the pathological processes underlying the motor deficits of Parkinson’s disease, the neural mechanisms underlying the dementing process and its associated cognitive deficits are still poorly understood. Recent insights from neuroscience research have begun to unravel the heterogeneous involvement of several distinct neural networks underlying the cognitive deficits in Parkinson’s disease dementia, and their modulation by both dopaminergic and non-dopaminergic transmitter systems in the brain. In this review we collate emerging evidence regarding these distinct brain networks to give a novel perspective on the pathological mechanisms underlying Parkinson’s disease dementia, and discuss how this may offer new therapeutic opportunities.

Region of the Nucleus Basalis of Maynert - a target for DBS

(picture from wikipedia.com)