Advanced Thinking Changes & Parkinson’s

Changes in thinking are common in Parkinson’s disease (PD). Early on, thinking can feel slower, or it may become harder to focus or multitask. As PD progresses, these changes may become more significant and develop into dementia — changes in thinking and behavior that affect daily tasks and independence.

It’s normal to feel worried, frustrated or scared about dementia. There are resources and support to help you understand what’s going on and find ways to manage.

Quick Facts

Dementia symptoms vary widely — but in Parkinson's, problem solving and attention are often affected earlier than memory.
Symptoms usually develop slowly over time.
Treatments, support and changes at home can help with symptoms and improve quality of life.

Signs of Dementia in Parkinson's:

Thinking changes significant enough to impact daily living
Fluctuations in alertness and attention
Depression, anxiety and irritability
Vision changes, such as misinterpreting what’s seen — especially in low light
Trouble finding words or following conversations
Getting lost, even in familiar places
Hallucinations (seeing or hearing things that aren’t there)
Delusions (strong beliefs not based in reality)
Sleep problems

Types of Dementia in Parkinson's

There are two main types of dementia that are related to Parkinson’s symptoms. Both are linked to abnormal protein buildup in the brain called Lewy bodies. These conditions can look similar, which sometimes makes them hard to tell apart. The key difference is timing:

Parkinson’s disease dementia (PDD): Dementia develops more than a year after movement symptoms start — often many years later.
Dementia with Lewy bodies (DLB): Dementia and movement symptoms start at the same time or within a year of each other. People with DLB may also have pronounced changes in attention and alertness that come and go.

Diagnosing Dementia in Parkinson's

Doctors diagnose dementia by reviewing symptoms, medical history and medications. They may also use brain scans or thinking tests. Neurologists and psychologists can also play a role in diagnosis.

Other issues like depression, infections or sleep problems can cause similar symptoms or worsen thinking problems and need to be ruled out. Dementia usually develops slowly. If thinking changes happen suddenly, doctors will look for other causes, like urinary tract infections.

Treatment Options

There isn't a cure for dementia, but treatments and support can help people manage symptoms and promote well-being.

Medications

Some Alzheimer’s medications may help PD-related dementia.
Antidepressants can support mood.
For hallucinations, some antipsychotic medications may be helpful.

Some medicines can worsen thinking or cause hallucinations. These can include Parkinson’s drugs that boost dopamine (especially at higher doses), anticholinergics, older antidepressants and allergy medicines, such as Benadryl. If this happens, a doctor may adjust or stop them.

Non-Medication Strategies

Thinking and communication support: Psychologists and speech-language pathologists can offer thinking skill exercises and help with communication challenges.
Consistent routines: Having regular times for meals, sleep, medication and activities can reduce confusion and stress.
Safety and home changes: Occupational therapists can suggest ways to make the home safer and easier to navigate.
Physical activity: Regular movement like walking, stretching or dancing can improve mood, sleep, thinking and memory.
Meaningful engagement: Music, art, puzzles, hobbies and time with others can spark joy, reduce isolation and help people maintain a sense of purpose and identity.

Tips for Living with Dementia

Staying emotionally connected

Early on, counseling, support groups and online dementia programs can bring comfort and a sense of belonging. Later, familiar music, quiet time together and gentle touch can help people feel close and cared for.

Planning ahead

Early conversations about routines, care and legal matters — such as wills and powers of attorney — can make future decisions easier. Elder law attorneys may help guide this process.

Supporting care partners

Breaks, support groups, movement and help from trusted people can ease stress and reduce burnout.