En español | Many symptoms of Parkinson's disease — shuffling gait, quivering hands, stooped posture — are easy to spot. But this disease can also cause problems that are far less visible but no less distressing. Perhaps the most worrisome is cognitive decline, which affects about 50 percent of patients.
"This is a scary, confusing and concerning topic for a lot of people,” says neurologist Rachel Dolhun, M.D., senior vice president of medical communications at the Michael J. Fox Foundation. While these feelings are natural, common misconceptions can exacerbate patients’ fears.
For starters, cognitive decline doesn't necessarily equal full-blown dementia, and many people with Parkinson's develop only mild impairment. Another misconception is that even slight memory slippage signals that rapid deterioration is imminent — but that's far more common with Alzheimer's disease than it is with Parkinson's, says Tsao-Wei Liang, M.D., chief of the movement disorders division at Jefferson Health. “It's not always relentlessly progressive, and more often than not, symptoms can be managed with medication, caregiver support and basic organizational strategies,” he says.
It's also important to know that many Parkinson's patients with some cognitive impairments are able to form new short-term memories, even if they struggle with attention and multitasking. “People with Parkinson's will often remember [something recently discussed] if you give a clue or prompt them,” Dolhun says.
What muddles memory
Parkinson's is a neurodegenerative condition, so it's not surprising that memory loss is often part of it. The disease is associated with a decline in acetylcholine, a neurotransmitter that's important for memory, Liang explains. In patients who have more serious dementia, the buildup of alpha-synuclein proteins (also called Lewy bodies) in areas of the brain that are important for memory, thinking or language is likely to blame, says Michael Okun, M.D., national medical adviser to the Parkinson's Foundation and executive director of the Norman Fixel Institute for Neurological Diseases at University of Florida Health.
Research confirms that alpha-synuclein plays a major role, but tau and amyloid beta (two proteins that have been linked with Alzheimer's disease) may also be factors in some patients. A 2019 review of studies, published in the Journal of Neurology, Neurosurgery, & Psychiatry, found that a significant number of deceased Parkinson's patients who suffered from dementia also had tau and amyloid-beta buildup in their brains.
It's worth noting that not everyone with Parkinson's faces an equal risk of memory trouble. Those who develop cognitive impairment tend to be older and living with the disease for longer. Patients who have the most severe motor problems and require high doses of dopamine-promoting medication are also at greatest risk, according to research published in Movement Disorders.
How to stay sharp
Several studies aimed at identifying various subtypes of Parkinson's disease are underway. These projects — including the Parkinson's Outcomes Projects, the Parkinson's Progression Markers Initiative and the Alzheimer's Disease Neuroimaging Initiative — might one day yield information that could help doctors flag patients at greatest risk of specific complications, including dementia, earlier in the disease process. In the meantime, there are steps you can take to lower the risk of memory problems or catch them as soon as possible.
Preventive strategies are largely aimed at broadly promoting good brain health. Regular exercise is important, and even people who've developed substantial motor problems can find classes or activities that work for their level or are specifically for people with Parkinson's. (Check out Rock Steady Boxing and Pedaling for Parkinson's.) Dolhun says that maintaining strong social ties and eating a healthy, balanced diet — such as the Mediterranean, with its emphasis on anti-inflammatory fatty fish, whole foods and plenty of antioxidant-rich fruits and vegetables — are essential, too.
Crossword puzzles are fine, as is mixing things up, Okun says. “Do something with your left hand if you're right-handed,” he says. He also encourages patients to listen to audiobooks with a partner or caregiver, stopping after each chapter and having a discussion to ensure that both parties can reiterate what happened (if not, repeat the chapter).
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If you're experiencing memory problems, inform your medical provider right away. Your doctor should start by screening you for other conditions that mimic Parkinson's-related memory loss, Okun says, including depression, thyroid disease, vitamin deficiencies and urinary tract infections.
Your physician should also review all your medications, because even seemingly innocuous over-the-counter drugs and supplements can be problematic. Benadryl (diphenhydramine), for instance, may cause cognitive problems because it blocks acetylcholine.
When in doubt, ask your doctor to refer you to a neuropsychologist for a full workup. Neuropsychological testing takes a few hours, but it should yield useful information about your mental status so that you can be properly treated and monitored. Depending on the results, your doctor may recommend that you work with an occupational therapist on organizational strategies or participate in a cognitive training program. Your doc may also prescribe Exelon (rivastigmine), a drug that boosts cognition by increasing the amount of acetylcholine in the brain.
Whatever your level of functioning, it's always wise to raise any questions you have about your memory with your neurologist. “Your doctor might focus on motor symptoms, but if you're concerned, you should absolutely talk to your doctor and ask what you can do,” Dolhun says. “Be your best advocate.”