How Does Parkinson’s Relate to Various Forms of Dementias?

April 25, 2024

We've come to recognize the intricate relationship between Parkinson's disease and dementia, with Parkinson's patients being particularly susceptible to developing dementia over time.  You can review this correlation by visiting our past article here.  However, dementia isn't a singular condition; it encompasses various forms with distinct characteristics. So, how exactly does Parkinson's intersect with these different types of dementia? 

Today, let’s explore Parkinson's disease and its connection to various forms of dementia, as well as the specific symptoms associated with each type of dementia to highlight the unique challenges faced by individuals living with these conditions. 

Dementia and Parkinson’s 

As long ago as the 7th Century, physicians and laypeople used the term ‘demented’ to describe patients suffering from cognitive and memory issues, or an uncontrollable tremor.  The origins of dementia, and its various forms, remained a mystery until quite recently, when researchers began to identify causes and symptoms with greater accuracy.  They also began to connect the dots on how certain dementias were connected to other neurodegenerative diseases, such as Parkinson’s Disease.  Now, we can discuss in detail some of the causal factors behind the range of dementias, which affect 5-6 million Americans, and understand how some of these forms may be linked to Parkinson’s Disease.1 

We’ve seen that dementia is prevalent in Parkinson’s patients, especially the older cohort.  This is partly because there is, on average, a ten-year gap between a PD diagnosis and the onset of dementia.2  Patients who experience hallucinations, excessive daytime sleepiness, and more severe motor problems are at a higher risk for dementia.3, 4 

We also saw that protein misfolding, which can create Lewy Bodies, is associated not only with PD but with all dementia types.  When several forms of dementia present simultaneously, this is known as ‘mixed dementia’.  Though there are a lot of acronyms to absorb, it’s valuable to understand the different types of dementia, as they present in unique ways, and some can ‘masquerade’ as Parkinson’s Disease Dementia (PDD).  

The Types of Dementia 

 

  • Mild cognitive impairment (MCI) is a condition marked by memory or cognitive issues that are more serious than others in the patient’s age group.5  MCI is not dementia, per se, but is described as a transitional stage between normal cognitive function and dementia.6  Family and friends might notice increased forgetfulness, trouble finding the right word, movement difficulties and changes in the sense of smell, but there won’t be major implications for daily life.7  Studies are ongoing, but among seniors (65 and older), roughly 10-20% of MCI patients will develop more serious memory and cognitive issues, and almost half of PD patients live with MCI.8  Development of dementia is far from a certainty, and some patients find their symptoms improving, depending on the causes of their MCI, which can include neurodegenerative illnesses but also sleep trouble, diabetes, stroke and the use of some medications.7 

It's crucial to distinguish between normal signs of aging and more worrisome indicators.  While some degree of cognitive decline is expected with age, recognizing when it may signify a more advanced decline, such as dementia or Alzheimer's Disease, can be challenging.  To help navigate this, we offer a free checklist for assessing aging behavior. Download it here.  

  • Parkinson’s Disease Dementia (PDD) emerges slowly, with the average onset occurring ten years after the initial PD diagnosis.9  One study showed that around 30% of all PD patients are later diagnosed with dementia, while another found that almost half will receive this diagnosis within ten years of their initial PD finding.8,10  

As we’ve seen, the protein alpha-synuclein is very much involved. In the brains of dementia sufferers, this protein becomes misfolded, resulting in: 1) the creation of sticky protein clumps which are ubiquitously found in the brains of PD and Alzheimer’s sufferers; 2) the formation of Lewy Bodies, which worsen brain health by drawing alpha-synuclein out of the nucleus of brain cells, where it is needed to perform DNA repair.11  

A diagnosis of PDD is made when there is impairment in the patient’s attentiveness, executive functions, spatial awareness, memory, and language use.  Movement problems are visible at the onset, with memory issues found much later in the progression of PDD.12  

  • Parkinson’s and Lewy Body Dementia (LBD) or Dementia with Lewy Bodies (DLB) 

It’s worth repeating the main culprit: misfolded alpha-synuclein proteins create clumps called Lewy Bodies.   The presence of Lewy Bodies shifts a patient’s diagnosis to LBD/DLB, a disease highlighted by the sad death of comedian Robin Williams (1951 – 2014), and in fiction, through Kelsey Grammer’s character in Boss (2011-12).  Found mainly among seniors and affecting around 1.4 million Americans, the disease is progressive, i.e., it worsens over time, and on average, patients survive for 5-8 years, although there are outliers.13  A risk factor for LBD/DLB is REM Sleep Behavior Disorder, where a sleeping person physically acts out their dreams.14 

LBD/DLB is the second most common form of dementia, affecting 10-15% of dementia sufferers.  It can develop independently, or connect to PD/PDD.  There is considerable crossover between the two sets of symptoms, including changes in cognition (memory, thinking skills), movement and behavior, although memory issues emerge sooner than in cases of PDD.13  Convincing, persistent, and often frightening hallucinations affect 80% of LBD/DLB sufferers, and these can include objects (e.g., a pile of clothes misapprehended as a doll) insects and other animals, and miniature people.15  Delusions and paranoia are also common.16 

  • Alzheimer’s Disease (AD) 

Lewy Bodies are also found in the brains of AD sufferers.17  AD is fatal and its symptoms are even more disabling than those of PD, including an earlier onset of language issues and an inability to form new memories.18 

Then, there are three types of dementias that can ‘masquerade’ as Parkinson’s: 

  • Vascular Parkinsonism is a form of dementia which is caused not by neurodegeneration but by impaired blood flow to the brain, often resulting from mini strokes that affect the substantia nigra (the area of the brain most connected to PD).  Sometimes called ‘atypical Parkinsonism’, it affects the lower body, resulting in the characteristic shuffling gait, but not hand tremors.  
  • Corticobasal Syndrome (CBS), a form of Frontotemporal Dementia (FTD), in which the frontal and temporal lobes are shrunk following the death of neurons.  CBS brings about movement issues that closely match those of PD; rigidity and tremor in CBS also have the characteristic asymmetrical (unequal) bodily effects.  83% of CBS patients reported the ‘alien limb’ phenomenon, in which an arm or leg feels estranged or seems to have ‘a mind of its own’.19  Sophisticated tests are needed to differentiate neural protein issues in CBS from those signifying PD or other forms of dementia.20 
  • Progressive Supranuclear Palsy (PSP) is another form of FTD which affects motor function and balance in much the same way as PD, and it is often mistaken for PD in its earliest stages.  However, PSP has a generally later onset (mid- to late-sixties) and progresses quickly, resulting in severe disability within 3-5 years of the first symptoms.21  Speech problems emerge earlier than in PD, and while PD sufferers tend to lean forward as a result of rigidity, PSP patients lean back, often resulting in falls and head injuries.   

Strategies for Slowing and Reducing the Risk of Dementia with Parkinson’s 

As you might expect, lifestyle choices can have an important role in reducing risk or slowing the progression of neurodegenerative diseases.  The recommendations include: 

  • High-intensity Exercise encourages the production of the key neurotransmitters which are affected by PD and other neurodegenerative ailments.  In one study, participants who exercised three times a week for six months and regularly reached 80-85% of their age-appropriate maximum heart rate experienced less severe motor symptoms.22  
  • Sleep can be difficult for PD sufferers, who might experience REM sleep disorders, or find that their tremors wake them up.  Avoiding naps can help, and researchers advise careful consideration of sleep hygiene, i.e., the environment in which we sleep, to eliminate excess light, noise, movement, and sources of stress.23 

  • Nutrition is a key weapon against neurodegeneration.  Carefully planned diets including the keto diet and the MIND (Mediterranean Diet for Neurodegenerative Delay) diet can push back the onset of PD and decrease the level of disability.24 

RELEVATE, our brain health product, contains 17 clinically researched nutrients designed to support long-term brain health.  These nutrients are selected based on those found in brain-healthy diets like the Mediterranean and MIND diets. 

If you decide you’d like to sign up for a subscription of RELEVATE (a monthly delivery of brain boosting nutrition), click here now and use code APRILMIND to get an additional MIND diet meal planning pad, 6-day MIND meal planning inspiration sheet, colorful MIND diet food wheel, and a specially branded vitamin organizer.  Take action inside and outside the kitchen, for lasting brain health.   

Growing our awareness of cognitive and motor changes in our bodies can help us recognize when neurodegeneration might be occurring.  The founder of Neuroreserve, Dr. Edward Park, experienced a challenging, twenty-year journey with his father, who suffered from PD and PDD.  This journey led directly to his interest in neuroprotective treatments and inspired the formation of NeuroReserve, which has the aim of providing information and therapies for anyone concerned about long-term brain health.25 

Dr. Edward Park also created RELEVATE, a brain health nutritional supplement that helps bridge the gap between the ideal intake of nutrients for brain health and the Standard American Diet (SAD).  To learn more about RELEVATE, click here.  

If you’re interested in more brain-healthy tips, sign up here for our newsletter to get a FREE e-guide to help you learn "6 Steps to Build Lasting Brain Power”, plus receive evidence-based articles, tips, and recipes directly to your inbox.  

References 

  1. The Truth About Aging and Dementia | CDC. (n.d.). Retrieved April 23, 2024, from https://www.cdc.gov/aging/publications/features/Alz-Greater-Risk.html
  2. Aarsland, D., & Kurz, M. W. (2010). The Epidemiology of Dementia Associated with Parkinson’s Disease. Brain Pathology, 20(3), 633. https://doi.org/10.1111/J.1750-3639.2009.00369.X
  3. Aarsland, D., Andersen, K., Larsen, J. P., Lolk, A., & Kragh-Sørensen, P. (2003). Prevalence and Characteristics of Dementia in Parkinson Disease: An 8-Year Prospective Study. Archives of Neurology, 60(3), 387–392. https://doi.org/10.1001/ARCHNEUR.60.3.387
  4. Anang, J. B. M., Gagnon, J. F., Bertrand, J. A., Romenets, S. R., Latreille, V., Panisset, M., Montplaisir, J., & Postuma, R. B. (2014). Predictors of dementia in Parkinson disease: A prospective cohort study. Neurology, 83(14), 1253. https://doi.org/10.1212/WNL.0000000000000842
  5. What Is Mild Cognitive Impairment? (n.d.). Retrieved April 23, 2024, from https://www.alzheimers.gov/alzheimers-dementias/mild-cognitive-impairment 
  1. Cammisuli, D. M., Cammisuli, S. M., Fusi, J., Franzoni, F., & Pruneti, C. (2019). Parkinson’s Disease–Mild Cognitive Impairment (PD-MCI): A Useful Summary of Update Knowledge. Frontiers in Aging Neuroscience, 11. https://doi.org/10.3389/FNAGI.2019.00303
  2. What Is Mild Cognitive Impairment? | National Institute on Aging. (n.d.). Retrieved April 23, 2024, from https://www.nia.nih.gov/health/memory-loss-and-forgetfulness/what-mild-cognitive-impairment
  3. Weil, R. S., Costantini, A. A., & Schrag, A. E. (2018). Mild Cognitive Impairment in Parkinson’s Disease—What Is It? Current Neurology and Neuroscience Reports, 18(4). https://doi.org/10.1007/S11910-018-0823-9
  4. Parkinson’s Disease Dementia | Memory and Aging Center. (n.d.). Retrieved April 23, 2024, from https://memory.ucsf.edu/dementia/parkinsons/parkinson-disease-dementia
  5. Yu, R. L., & Wu, R. M. (2022). Mild cognitive impairment in patients with Parkinson’s disease: An updated mini-review and future outlook. Frontiers in Aging Neuroscience, 14, 943438. https://doi.org/10.3389/FNAGI.2022.943438/BIBTEX
  6. Schaser, A. J., et al. (2019). Alpha-synuclein is a DNA binding protein that modulates DNA repair with implications for Lewy body disorders. Scientific Reports 2019 9:1, 9(1), 1–19. https://doi.org/10.1038/s41598-019-47227-z
  7. Lewy Body Dementia: Symptoms, Stages, & Treatment. (n.d.). Retrieved April 23, 2024, from https://www.webmd.com/alzheimers/dementia-lewy-bodies
  8. What Is Lewy Body Dementia? Causes, Symptoms, and Treatments | National Institute on Aging. (n.d.). Retrieved April 23, 2024, from https://www.nia.nih.gov/health/lewy-body-dementia/what-lewy-body-dementia-causes-symptoms-and-treatments
  9.  Boot, B. P., Orr, C. F., et al. (2013). Risk factors for dementia with Lewy bodies: A case-control study. Neurology, 81(9), 833. https://doi.org/10.1212/WNL.0B013E3182A2CBD1
  10.  Onofrj, M., Taylor, J. , et al. (2013). Visual hallucinations in PD and Lewy body dementias: old and new hypotheses. Behavioural Neurology, 27(4), 479–493. https://doi.org/10.3233/BEN-129022
  11. Atypical Parkinsonism | Parkinson’s Disease. (n.d.). Retrieved April 23, 2024, from https://www.michaeljfox.org/news/atypical-parkinsonism#lewy-body-dementia
  12. Dementia with Lewy Bodies and Parkinson Disease Dementia - Neurologic Disorders - Merck Manual Professional Edition. (n.d.). Retrieved April 23, 2024, from https://www.merckmanuals.com/professional/neurologic-disorders/delirium-and-dementia/dementia-with-lewy-bodies-and-parkinson-disease-dementia
  13. Dementia | Parkinson’s Foundation. (n.d.). Retrieved April 23, 2024, from https://www.parkinson.org/understanding-parkinsons/non-movement-symptoms/dementia
  14. Graff-Radford, J., Rubin, M. N., Jones, D. T., Aksamit, A. J., Ahlskog, J. E., Knopman, D. S., Petersen, R. C., Boeve, B. F., & Josephs, K. A. (2013). The Alien Limb Phenomenon. Journal of Neurology, 260(7), 1880. https://doi.org/10.1007/S00415-013-6898-Y
  15. Chahine, L. M., Rebeiz, T., Rebeiz, J. J., Grossman, M., & Gross, R. G. (2014). Corticobasal syndrome: Five new things. Neurology: Clinical Practice, 4(4), 304. https://doi.org/10.1212/CPJ.0000000000000026
  16. Progressive Supranuclear Palsy (PSP) | National Institute of Neurological Disorders and Stroke. (n.d.). Retrieved April 23, 2024, from https://www.ninds.nih.gov/health-information/disorders/progressive-supranuclear-palsy-psp
  17. de Laat, B., Hoye, J., et al. (2024). Intense exercise increases dopamine transporter and neuromelanin concentrations in the substantia nigra in Parkinson’s disease. Npj Parkinson’s Disease 2024 10:1, 10(1), 1–7. https://doi.org/10.1038/s41531-024-00641-1
  18. Parkinson’s Disease: Sleep Disturbances and Fatigue | Sleep Foundation. (n.d.). Retrieved April 23, 2024, from https://www.sleepfoundation.org/physical-health/parkinsons-disease-and-sleep
  19. Metcalfe-Roach, A., Yu, A. C., Golz, E., Cirstea, M., Sundvick, K., Kliger, D., Foulger, L. H., Mackenzie, M., Finlay, B. B., & Appel-Cresswell, S. (2021). MIND and Mediterranean Diets Associated with Later Onset of Parkinson’s Disease. Movement Disorders, 36(4), 977–984. https://doi.org/10.1002/MDS.28464
  20. Edward Park – NeuroReserve Inc. (n.d.). Retrieved April 23, 2024, from https://neuroreserve.com/pages/edward-park
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