Table of ContentsView AllTable of ContentsSymptomsHallucinationsDiagnosisCausesRisk FactorsTreatmentLBD vs. PDDEnd-Stage PDDOutlookSeeking Medical Care
Table of ContentsView All
View All
Table of Contents
Symptoms
Hallucinations
Diagnosis
Causes
Risk Factors
Treatment
LBD vs. PDD
End-Stage PDD
Outlook
Seeking Medical Care
Parkinson’s disease dementia(PDD) is a feature ofParkinson’s disease, a progressive movement disorder associated with both motor (movement-related) and nonmotor symptoms.
Dementia causes symptoms like difficulties with memory and making decisions and changes in behavior and mood. It can develop on average about 10 years after PD-related movement symptoms, namely stiffness, shaking, slow movements (bradykinesia), and loss of balance.
Approximately 20% to 40% of people currently living with PD have dementia, and up to 80% of people with PD will eventually develop it.
This article reviews the symptoms, diagnosis, risk factors, and treatment of Parkinson’s disease dementia. It also helps distinguish PDD fromdementia with Lewy bodies(DLB), a condition with overlapping biologies and symptoms.
Jessie Casson / Getty Images
Symptoms of Parkinson’s Dementia
The symptoms of Parkinson’s dementia are classified as either cognitive or behavioral.
Cognitive symptoms include:
Behavioral symptoms include:
Parkinson’s Dementia and Hallucinations
Visual hallucinations are the most common type of hallucination in Parkinson’s dementia. Most are complex, in which a person sees vivid images, such as animals, faces, objects, or scenery, that are often familiar, lifelike, and not frightening.
In some instances, visual hallucinations are simple. A person may see moving dots, shapes, patterns, colors, or illusions of objects passing across the periphery of their vision.
Less commonly, auditory (hearing) hallucinations may occur in Parkinson’s disease, such as hearing muffled sounds.
Olfactory (smell), gustatory (taste), and tactile (feel) hallucinations also develop on occasion, although, if present, they tend to coexist with visual hallucinations.
Confounding the picture is that some drugs used to treat Parkinson’s disease can aggravate visual hallucinations. These drugs include:
Hallucinations Treatment, Symptoms, and Causes
How Is Parkinson’s Dementia Diagnosed?
No single blood or imaging test on its own can diagnose Parkinson’s dementia. Instead, the diagnosis is clinical, based on a person’s medical history, symptoms, and physical examination.
Core features of the criteria include that a person has:
Interestingly, behavioral symptoms are supportive of a diagnosis of Parkinson’s dementia but are not required.
Lastly, before confirming a diagnosis of Parkinson’s dementia, other explanations for cognitive problems must be ruled out, such asstroke,depression, or a medication side effect.
What Causes Parkinson’s Dementia?
The development and spread of Lewy bodies (sticky clumps of the proteinalpha-synuclein) throughout the brain is linked to the development of Parkinson’s dementia.
These Lewy bodies are believed to impair the functioning of multiple chemical messaging systems within the brain, ultimately leading to the death of nerve cells that producedopamine.
It’s unclear exactly why or how these Lewy bodies form, although genetic, aging, and environmental factors (e.g., exposures to specific pesticides or metals) are likely involved.
Keep in mind that while brain damage in Parkinson’s dementia is primarily due to Lewy body formation, abnormal accumulation of two other proteins—amyloidandtau—are also believed to contribute. These two proteins are linked toAlzheimer’s disease.
Parkinson’s vs. Alzheimer’sParkinson’s disease and Alzheimer’s disease are progressive brain disorders that result in nerve cell death. However, Parkinson’s is primarily a movement disorder that cansometimescause dementia, whereas Alzheimer’s diseasealwayscauses dementia.
Parkinson’s vs. Alzheimer’s
Parkinson’s disease and Alzheimer’s disease are progressive brain disorders that result in nerve cell death. However, Parkinson’s is primarily a movement disorder that cansometimescause dementia, whereas Alzheimer’s diseasealwayscauses dementia.
Risk Factors for Developing Parkinson’s Dementia
Risk factors for Parkinson’s dementia are increasing age, longer disease duration, a more severe disease course, and older age at disease onset.
In addition, some early disease symptoms are linked to an increased risk of Parkinson’s dementia. These include the presence of:
Lastly, specific genetic markers—for example, the presence of the APOE-ε4 gene—andcerebrospinal fluidfindings (e.g., a low amount of Aβ1-42) also predict an increased risk for Parkinson’s disease.
Side NoteThe presence of the APOE-ε4 gene is also a risk factor for Alzheimer’s disease. Aβ1-42 is the major component of amyloid collections seen in the brains of people with Alzheimer’s disease.
Side Note
The presence of the APOE-ε4 gene is also a risk factor for Alzheimer’s disease. Aβ1-42 is the major component of amyloid collections seen in the brains of people with Alzheimer’s disease.
What Is Alzheimer’s Disease?
How Is Parkinson’s Dementia Treated?
There is no cure for Parkinson’s disease dementia; however, various therapies can ease symptoms to improve daily functioning and quality of life.
Medications for Parkinson’s dementia include:
Non-drug therapies for PDD include cognitive rehabilitation, exercise, physical therapy,music therapy, and art therapy.
Nuplaz (pimavanserin) is an antipsychotic approved for the treatment of Parkinson’s disease psychosis. Nuplaz is the only medication FDA-approved to treat hallucinations and delusions associated with Parkinson’s disease. Healthcare providers may prescribe medications like Nuplazid off-label to treat Parkinson’s dementia.
Lewy Body Dementia vs. Parkinson’s Disease Dementia
Like PDD, dementia with Lewy bodies (DLB) is a progressive, neurodegenerative condition associated with the buildup of Lewy bodies within the brain.
These complex diseases share various motor, cognitive, and behavioral characteristics, such as stiffness, slow movements, visual-spatial dysfunction, and visual hallucinations.
That said, a critical distinguishing feature is that Parkinson’s disease dementia occurs at least one year—but usually several years—after the onset of motor symptoms.
On the other hand, in DLB, dementia symptoms occur before or around the same time as the development of motor symptoms.
Other distinguishing features are:
Difference Between Alzheimer’s and Lewy Body Dementia
End-Stage Parkinson’s Dementia
Severe, debilitating symptoms mark end-stage Parkinson’s dementia. Worsening sleep problems and frequent hallucinations tend to occur, and individuals can become extremely confused, depressed, anxious, or hostile.
Besides symptoms of dementia, motor symptoms, such as frequentfreezing episodes(when they suddenly cannot move), prevent people from being able to walk or stand on their own.
Severe constipation, significant difficulty with speaking and swallowing, and complications like falls, malnutrition, dehydration, and weight loss are also common at the end stages of the disease.
End-Stage Parkinson’s and Signs of Increased Risk of Death
Outlook for Someone With Parkinson’s Disease Dementia
People with Parkinson’s disease dementia are at a higher risk of dying compared to the general population and to those with Parkinson’s disease without dementia.
In fact, some research suggests that a person with PDD lives an average of five to seven years. That said, there is no surefire way to predict the outlook for or life expectancy of any person with PDD, as it can vary considerably.
The best thing you can do if you or a loved one has Parkinson’s disease dementia is focus your energy on facets of life and of the disease you can control, such as staying hydrated, eating nutritiously, and engaging in physical activity (if possible).
Also, keep in close contact with your healthcare team, take your medication as prescribed, and reach out to loved ones, neighbors, or asupport groupfor comfort and social connection.
Worsening Parkinson’s Disease and Associated Triggers
When to Contact a Healthcare Provider
If you are experiencing thinking, memory, or behavior problems (whether or not you have been diagnosed with Parkinson’s disease), please make an appointment with a healthcare provider.
They can assess you for all possible causes of your cognitive/ behavioral concerns and refer you to a neurologist for additional diagnostic tests if deemed appropriate.
Summary
Symptoms of PDD include problems planning and concentrating, recognizing faces, and seeing or believing things that aren’t real (hallucinations and delusions). Sleep and mood problems like apathy (lack of motivation) are also common.
Unlike the related condition—dementia with Lewy bodies—PDD develops at least one year but usually several years after the onset of motor (movement-related) symptoms like stiffness and shaking.
Treatment of PDD aims at reducing symptoms and often includes a combination of medication and nondrug therapies like cognitive rehabilitation and exercise.
23 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
UCSF Memory and Aging Center.Parkinson’s disease dementia.
Åström DO, Simonsen J, Raket LL, et al.High risk of developing dementia in Parkinson’s disease: a Swedish registry-based study.Sci Rep. 2022;12(1):16759. doi:10.1038/s41598-022-21093-8
Hanagasi HA, Tufekcioglu Z, Emre M.Dementia in Parkinson’s disease.J Neurol Sci. 2017;374:26-31. doi:10.1016/j.jns.2017.01.012
Aarsland D, Taylor JP, Weintraub D.Psychiatric issues in cognitive impairment.Mov Disord. 2014;29(5):651-62. doi:10.1002/mds.25873
Maggi G, Trojano L, Barone P, Santangelo G.Sleep disorders and cognitive dysfunctions in Parkinson’s disease: a meta-analytic study.Neuropsychol Rev. 2021;31(4):643-682. doi:10.1007/s11065-020-09473-1
Weil RS, Reeves S.Hallucinations in Parkinson’s disease: new insights into mechanisms and treatments.Adv Clin Neurosci Rehabil. 2020;19(4):ONNS5189. doi:10.47795/ONNS5189
Vasconcellos LF, Pereira JS.Parkinson’s disease dementia: diagnostic criteria and risk factor review.J Clin Exp Neuropsychol. 2015;37(9):988-93. doi:10.1080/13803395.2015.1073227
Koros C, Stefanis L, Scarmeas N.Parkinsonism and dementia.J Neurol Sci. 2022;433:120015. doi:10.1016/j.jns.2021.120015
De Miranda BR, Goldman SM, Miller GW, Greenamyre JT, Dorsey ER.Preventing Parkinson’s disease: an environmental agenda.J Parkinsons Dis. 2022;12(1):45-68. doi:10.3233/JPD-212922
Hussain MW, Camicioli R.Nonmotor symptoms of Parkinson’s disease as predictors of dementia.Can J Neurol Sci. 2018;45(1):97-99. doi:10.1017/cjn.2017.239
Schrag A, Siddiqui UF, Anastasiou Z, Weintraub D, Schott JM.Clinical variables and biomarkers in prediction of cognitive impairment in patients with newly diagnosed Parkinson’s disease: a cohort study.Lancet Neurol. 2017;16(1):66-75. doi: 0.1016/S1474-4422(16)30328-3
Lim EW, Aarsland D, Ffytche D, et al.Amyloid-β and Parkinson’s disease.J Neurol. 2019;266(11):2605-2619. doi:10.1007/s00415-018-9100-8
Fyfe I.APOE*ε4 promotes synucleinopathy.Nat Rev Neurol. 2020;16(4):185. doi:10.1038/s41582-020-0335-5
Armstrong MJ, Okun MS.Diagnosis and treatment of Parkinson disease: a review.JAMA. 2020;323(6):548-560. doi:10.1001/jama.2019.22360
Wang HF, Yu JT, Tang SW, et al.Efficacy and safety of cholinesterase inhibitors and memantine in cognitive impairment in Parkinson’s disease, Parkinson’s disease dementia, and dementia with Lewy bodies: systematic review with meta-analysis and trial sequential analysis.J Neurol Neurosurg Psychiatry. 2015;86(2):135-43. doi:10.1136/jnnp-2014-307659
Tamtaji OR, Reiter RJ, Alipoor R, Dadgostar E, Kouchaki E, Asemi Z.Melatonin and Parkinson Disease: Current Status and Future Perspectives for Molecular Mechanisms.Cell Mol Neurobiol. 2020 Jan;40(1):15-23. doi:10.1007/s10571-019-00720-5
Goldman JG, Holden S.Treatment of psychosis and dementia in Parkinson’s disease.Curr Treat Options Neurol. 2014 Mar;16(3):281. doi:10.1007/s11940-013-0281-2
Jellinger KA.Dementia with Lewy bodies and Parkinson’s disease-dementia: current concepts and controversies.J Neural Transm (Vienna). 2018;125(4):615-650. doi:10.1007/s00702-017-1821-9
Utsumi K, Fukatsu R, Hara Y, Takamaru Y, Yasumura S.Psychotic features among patients in the prodromal stage of dementia with Lewy bodies during longitudinal observation.J Alzheimers Dis. 2021;83(4):1917-1927. doi:10.3233/JAD-210416
Taylor JP, McKeith IG, Burn DJ, et al.New evidence on the management of Lewy body dementia.Lancet Neurol. 2020;19(2):157-169. doi:10.1016/S1474-4422(19)30153-X
Luquin M-R, Kulisevsky J, Martinez-Martin P, Mir P, Tolosa ES.Consensus on the definition of advanced Parkinson’s disease: a neurologists-based Delphi study (CEPA Study).Parkinsons Dis.2017;2017:4047392. doi:10.1155/2017/4047392
Savica R, Grossardt BR, Bower JH, et al.Survival and causes of death among people with clinically diagnosed synucleinopathies with parkinsonism: a population-based study.JAMA Neurol. 2017;74(7):839-846. doi:10.1001/jamaneurol.2017.0603
Meet Our Medical Expert Board
Share Feedback
Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit
Was this page helpful?
Thanks for your feedback!
What is your feedback?OtherHelpfulReport an ErrorSubmit
What is your feedback?
