Many people with Parkinson’s disease (PD) experience some degree of cognitive change, such as slowness of memory, changes in thinking, trouble focusing or difficulty finding words. Dementia is a permanent cognitive change that interferes with daily activities and quality of life. Identifying thinking changes early and discussing them with your doctor are the first steps in treating or ruling out PD-related dementia.

This article is based on a Parkinson’s Foundation Expert Briefing Let’s Talk About Dementia presented by Dr. James Leverenz, Director, Lou Ruvo Center for Brain Health at Cleveland Clinic, a Parkinson’s Foundation Center of Excellence.

Slowed movement, tremor and stiffness are some of the visible movement signs of Parkinson's disease. Though not visible, the impact of non-movement symptoms can be even more challenging for people with PD and their loved ones — this includes issues with thinking and memory. While PD-related cognitive change can be mild, between 60 to 80% of people living with PD for 15 years or more can experience disease-related dementia. Awareness of thinking changes can ensure early treatment.

Lewy Body Dementias

In Parkinson’s, the protein alpha-synuclein misfolds and forms clusters in the brain called Lewy bodies. These sticky clusters upset normal brain function. Lewy bodies are strongly linked to PD and dementia.

Nearly 1.5 million Americans are impacted by Lewy body dementias, including those living with:

• Parkinson’s disease dementia (PDD): diagnosed when significant cognitive decline occurs in someone living with Parkinson’s movement symptoms for a year or more (usually several years).
• Dementia with Lewy bodies (DLB): diagnosed when cognitive decline occurs before or at the same time as motor symptoms.

Almost 50% of people with Alzheimer's disease also have some Lewy body brain abnormalities. These are frequently seen in both people who live with sporadic and familial forms of Alzheimer's. When these changes go beyond a part of the brain called the amygdala, people often have some of the same symptoms as people living with dementia with Lewy bodies , frequently developing Parkinson's-like motor symptoms. This is known as the Lewy body variant of Alzheimer disease.

Some researchers theorize that Alzheimer's disease may drive clumping of Lewy bodies. New therapies designed to slow Alzheimer's progression could also hold possibility to slow Lewy body development — another reason for the importance of an early and correct diagnosis, and early treatment.

Dementia Signs and Symptoms

In addition to memory, thinking and behavior changes, other symptoms include:

• apathy
• depression
• poor insight
• executive dysfunction
• visual-spatial difficulties
• disruptive agitation
• psychosis (hallucinations and delusions)

Despite many shared symptoms across Lewy body dementia diseases, people often store and recall information differently, depending on which cognitive disorder they are living with.

Adding and retaining new memories is often difficult for people living with Alzheimer's disease. It may be challenging for someone with Alzheimer's to remember a question or conversation just minutes after, or they may have forgotten events from the previous day. Encoding new information can be an issue. However, if a person experiencing PD thinking changes struggles retrieving a memory, they can often pull it up with a clue or a reminder.

This means people with PD dementia can store memories. Rather than primary encoding difficulty, they often experience retrieval challenges — an executive dysfunction similar to difficulty multitasking or staying on track during conversations.

People with Alzheimer’s disease tend to have less awareness that they are hallucinating. A person with PD dementia or dementia with Lewy bodies can more often recognize that they are experiencing hallucinations. It’s important for the care provider to ask the person experiencing changes “Do you see things?” People with PD-related dementia will often acknowledge that they do see things, are aware the hallucinations are not real and are not bothered by what they see.

Diagnosing Lewy Body Dementias

Ensuring the person living with thinking changes receives the correct diagnosis is important. When diagnosing dementia, a doctor, neurologist or other healthcare expert will look for the ability to retrieve retained memories, early executive dysfunction or multitasking difficulties.

A review of symptoms, medications, medical history and more are also key to an accurate diagnosis. Your doctor will also rule out other medical illnesses — urinary tract infections or pneumonia can be related to sudden confusion and agitation.

Work with your doctor to identify any medications that might impact symptoms. Some medicines can cause or worsen confusion and hallucinations, including:

• Certain dopamine-boosting medications that ease movement at lower doses but may worsen thinking problems at higher doses
• Old antipsychotics, such as haloperidol, and anticholinergic (acetylcholine-blocking)
• Medications, such as trihexyphenydil, sometimes used to treat tremor

Therapies

Medications used in Alzheimer’s disease have benefits in PD dementia, including rivastigmine, donepezil and galantamine. Selective serotonin reuptake inhibitors (SSRIs), used for depression, may also be beneficial.

For people with Parkinson’s experiencing rapid eye movement (REM) sleep behavior disorder, your doctor might recommend the over-the-counter sleep aid melatonin. Clonazepam is frequently used if melatonin is not effective, although it can cause confusion, daytime sleepiness and other side effects.

Cognitive remediation, provided by a neuropsychologist or speech-language pathologist, focuses on strengthening cognition.

Behavior management modifies activities and environments to improve abilities and independence. It includes creating a daily routine, decluttering living spaces, increasing lighting and using assistive tools to reduce confusion.

Exercise, physical activity and social connection can also benefit cognitive health.

On the Horizon

Research is currently underway to better understand dementia and discover disease-specific therapies. Diagnosing and treating the earliest stages of thinking change can ensure early lifestyle adjustments and the best chance for responsive therapy.

Understanding the biological differences behind the development and onset of all Lewy body dementias will be essential to future disease-specific therapies.

Scientists are currently working to standardize testing of blood and body fluids to reveal amassed Lewy body alpha-synuclein. This could serve as an early detection tool for neurodegenerative disorders related to the protein, such as PD.

Biomarkers for the Lewy Body Dementias, a National Institutes of Health-funded study, recently awarded more than $10 million to the Cleveland Clinic to expand the national Dementia with Lewy Bodies Consortium. A collaboration with several Parkinson’s Foundation Centers of Excellence and others, the coalition accelerates research to improve diagnosis and treatment of dementia with Lewy bodies, including Parkinson’s disease dementia.

People who experience rapid eye movement (REM) sleep behavior disorder (RBD) are at risk for developing Lewy body dementias. This risk factor might be another potential early diagnosis clue or cue to begin preventative future preventative therapies as they become available.

Learn More

The Parkinson’s Foundation believes in empowering the Parkinson’s community through education. Learn more about PD and dementia by calling our free Helpline at 1-800-4PD-INFO (1-800-473-4636) or visiting Parkinson’s Foundation resources below.

• Read Cognition: A Mind Guide to Parkinson's Disease or explore other educational resources in our PD Library.
• Listen to the podcast episode: What is Lewy Body Dementia and How Does it Relate to Parkinson’s?
• Improve care for people with PD through professional education opportunities.

Each year, the Parkinson’s Foundation proudly recognizes four volunteers who have gone above and beyond to make life better for people living with Parkinson’s disease.

Their stories are powerful reminders of how passion, creativity and dedication can drive real change in our community.

✨ Take a look at this year’s 2025 National Volunteer Award winners and watch this video to hear what inspires them to take action!

Vikas Chinnan – California Chapter
Paul Oreffice Volunteer of the Year

This is our highest honor, recognizing a volunteer whose leadership and dedication have made a broad, lasting impact — both locally and nationally.

“Being a resource is one of the most rewarding things I’ve had the opportunity to do. I’m glad I found the Foundation when I did because it provided a lifeline to me and I’d like to pay it forward.”

Holly Bloom – South Central Chapter
Rising Star

Awarded to a new volunteer who made an immediate and powerful impact in their first year.

“Without all the resources that are available, I think I would struggle to find what was right for my husband. This cause is so important to me because it gives me hope and it allows me to be actively involved so that I don’t feel hopeless.”

Susan Brown – Georgia Chapter
Top Fundraiser

This award honors the individual who raised the highest total in donations over the past fiscal year.

“If you are thinking about volunteering, don’t underestimate what you can bring to the cause and to even just another person. You can volunteer in big ways and in small.”

Rose Lang – Florida Chapter
Community Service Award

Recognizing the volunteer who logged the most service hours in the past year.

“I’ve been an Ambassador now for about five years and my focus has always been to educate and empower members of our community, and to provide the resources and access to those resources that will help others, especially with an emphasis on safety when hospitalized.”

There are many ways to make a difference and support the Parkinson’s Foundation. Get started with our How You Can Help page. This page will give you options for volunteering, starting your own DIY Fundraiser, or even just donating to the cause.

You can also fill out a volunteer interest form to chat with our volunteer engagement team about how we can best put your skills to use. Help us bring life-saving information and resources to the hands of those who need them most.

Already a volunteer? Check out our course offerings today!

La enfermedad de Parkinson (EP) afecta a las personas de diferentes maneras, lo que representa un desafío para el desarrollo de nuevos tratamientos y terapias. PD GENEration: trazando el futuro de la enfermedad de Parkinson (PD GENEration: Mapping the Future of Parkinson’s Disease), el estudio global de la Parkinson's Foundation que ofrece pruebas y consejería genética sin costo para las personas diagnosticadas con la EP, está ayudando a los investigadores a superar este reto mediante la creación de una amplia base de datos genéticos para su análisis.

La diversidad de datos —es decir, tener información genética acerca de la EP de personas de todo el mundo— crea una base sólida para impulsar los avances en la investigación. Sin embargo, los miembros hispanos y latinos de la comunidad de la EP a menudo enfrentan barreras significativas tanto para vivir bien con la enfermedad de Parkinson como para participar en la investigación. Con esto en mente, la Parkinson’s Foundation se ha asociado con el Consorcio Latinoamericano de Investigación sobre la Genética de la Enfermedad de Parkinson (LARGE-PD, por sus siglas en inglés) para llevar el estudio PD GENEration a nuevos países.

Esta expansión no sólo fortalece la base de datos genéticos de la EP para uso de los investigadores, sino que también fomenta el objetivo del estudio de proporcionar pruebas y consejería genética a todas las personas diagnosticadas con la EP, sin importar en qué parte del mundo se encuentren.

Preparar una expansión exitosa

Expandir un estudio a nuevos países requiere tiempo, esfuerzo y planificación para que todo salga bien. Para ayudar a dicha expansión, PD GENEration colabora estrechamente con LARGE-PD, un estudio genético de la EP que se desarrolla en Latinoamérica desde 2006.

"Realizamos encuestas para entender el modelo de los sistemas de salud, que varían según el país y la institución, y la mejor manera de integrar los dos estudios para obtener los datos de mayor impacto", dijo Rebeca De León, directora de investigación clínica de la Parkinson's Foundation.

En 2024, se eligieron cinco centros LARGE-PD para comenzar a ofrecer pruebas y consejería genética de PD GENEration en Colombia, Chile, México, Perú y El Salvador. En colaboración con Indiana University School of Medicine, se diseñaron e implementaron programas de formación especializada en estos centros para garantizar que los resultados genéticos se devolvieran a los participantes. En tan sólo unos meses, estos centros inscribieron a 1,015 nuevos participantes y certificaron a 26 médicos para que devolvieran los resultados de las pruebas genéticas.

"El acceso a las pruebas y la consejería genética ha sido una laguna importante en LATAM", dijo el Dr. Ignacio Mata, coordinador de LARGE-PD y profesor de la Cleveland Clinic. "PD GENEration es un gran paso hacia la medicina de precisión, ya que proporciona a médicos y pacientes la información genética necesaria para ofrecer el mejor tratamiento posible a cada individuo".

Mantener el impulso

La Parkinson's Foundation está entusiasmada por continuar esta exitosa colaboración en América Latina, trabajando para proporcionar pruebas genéticas y asesoramiento a más personas con la enfermedad de Parkinson. Próximamente, PD GENEration incorporará nuevos centros en Argentina, Brasil, Honduras y Uruguay, ampliando así el acceso al estudio a un número aún mayor de países.

"Hemos establecido una sólida red de colaboración con centros de investigación y especialistas locales, facilitando enormemente la integración del estudio en cada país", dijo Anny Coral-Zambrano, gerente senior de Investigación Clínica de la Parkinson's Foundation. "Hoy, el proceso funciona sin problemas gracias a las soluciones innovadoras que hemos implementado".

Las campañas de divulgación en los alrededores de los sitios existentes también están ayudando a informar del estudio a las comunidades locales de la EP. "Para apoyar el reclutamiento, hemos estado llevando a cabo eventos educativos acerca de la investigación en los que ofrecemos el estudio", dijo Rebeca. "Algunos centros  incluso se desplazan a zonas remotas para prestar servicios médicos y ofrecer el estudio a quienes no pueden llegar a los centros".

El primer evento de PD GENEration en la Ciudad de México atrajo a más de 200 asistentes, de los cuales 82 se inscribieron al estudio en el evento. El evento contó con paneles acerca del Parkinson, la cognición, el ejercicio y la investigación y con la participación de más de 20 médicos. Un evento inaugural similar en Cali (Colombia) contó con 215 asistentes y ofreció una clase de zumba, actividades de estimulación cognitiva y un panel de expertos en genética.

El futuro de PD GENEration en América Latina

Con PD GENEration ahora activo en varios países de América Latina y llegando a más comunidades tradicionalmente desatendidas por la investigación de la EP, más personas que viven con esta enfermedad pueden obtener información valiosa acerca de su enfermedad a través de las pruebas y consejería genética. A medida que  aumente la diversidad de la información genética en la base de datos de PD GENEration, también lo hará la comprensión de la enfermedad por parte del campo de investigación de la EP, lo que permitirá impulsar avances significativos en su tratamiento.

En el proceso de expansión, los líderes de PD GENEration en la región han adquirido aprendizajes clave sobre cómo interactuar con poblaciones diversas, lecciones que fortalecerán las estrategias de divulgación e impacto del estudio en el futuro.

Las colaboraciones con consorcios como LARGE-PD permiten que la comunidad avance unida hacia un futuro en el que las personas con EP puedan vivir mejor gracias a mejoras continuas en la atención médica y en la investigación científica.

Aprenda más acerca de PD GENEration e inscríbase hoy mismo.