Dopamine Improves Cognitive Function in Mild-to-Moderate Alzheimer Disease
A study randomized clinical trial,, funded by the Alzheimer Drug Discovery Foundation (ADDF), provides evidence that rotigotine improves cognitive function in mild-to-moderate Alzheimer disease (AD). Although rotigotine did not significantly improve memory, executive function and ability to perform activities of daily living were both improved.
Current treatments for AD act on the neurotransmitter acetylcholine, but research has suggested that dopamine also plays a key role in the disease. Investigators focused on changes in the frontal lobe because dopamine modulates activity in this section of the brain. The improvements patients experienced in frontal-lobe controlled cognitive functions corresponded with a lab test showing that rotigotine enhanced dopaminergic pathways reaching this section of the brain. Investigators used novel biomarker tests, a combination of transcranial magnetic stimulation and electroencephalography recordings, to understand how rotigotine affects brain connectivity and function.
"Patients treated with rotigotine in this study had some practical improvements that are very important for people with AD," said Howard Fillit, MD, ADDF founding executive director and chief science officer. "Rotigotine improved executive function, which helps patients with key cognitive tasks, such as reasoning, judgment, working memory, and orientation. It also improved their ability to complete routine daily activities like shopping, planning, and even bathing, toileting, and feeding themselves, which means preserving their independence longer and reducing the burden on caregivers."
"This study is an important step forward in showing that Alzheimer disease patients may benefit from a combinations of drugs that enhance brain functions by interacting with different neurotransmitter systems," said lead investigator Dr. Koch.
"The ADDF has a long history of supporting trials like this that repurpose existing drugs because it can speed up our ability to find new treatments for AD," said Dr. Fillit. " At the ADDF we focus on funding trials that target novel pathways implicated in AD, beyond beta-amyloid and tau, because AD is a complex disease caused by multiple factors. Among these, addressing abnormalities in dopaminergic pathways holds great promise."