How Does Parkinson’s Relate to Dementia?

April 22, 2024

April is Parkinson’s Disease Awareness Month, which is the perfect time to learn about this disease and its impact on health.  Several other illnesses are linked to Parkinson’s, or have similar symptoms; remember that dementia is not a disease in itself, but a collection of symptoms caused by one or more disorders that affect the brain.1,2  Today, we’re going to take a deep dive into how Parkinson’s disease and dementia can be linked.  

Stay tuned for later this week when we discuss the different forms of dementia that may arise with Parkinson’s disease.  

Parkinson’s Disease (In Brief) 

Parkinson’s disease (PD) is one cause of dementia, though it’s not the only one.  This is a neurodegenerative disorder, i.e., it involves damage to brain cells.  The earliest signs of damage are in the neurons which link the brain and the gut, and those which govern our sense of smell.  The damage then spreads to the substantia nigra, an area of the brain which helps control movement and produces dopamine, a crucial neurochemical.  Further neuronal degeneration throughout the brain causes cognitive problems.3  

The main culprit behind this gradual damage is a protein called alpha-synuclein.  In its normal state, it is harmless, but when the brain becomes inflamed, a toxic form of the protein is created, eventually forming protein clumps called Lewy Bodies.  These sticky clumps are found in the brains of patients with various types of dementia, which suggests a connection between alpha-synuclein processing and the development of neurogenerative illnesses. 

The motor symptoms of PD have been understood for about 200 years. They are: 

  • Tremor:  shaking affecting the feet, jaw, and hands  
  • Bradykinesia:  unusually slow movements, even during familiar tasks  
  • Rigidity:  stiffness in the muscles, which remain almost permanently tensed up  
  • Postural Instability:  impaired balance and visible changes in posture4

PD also results in a range of non-motor symptoms which include disturbed sleep, depression, sciatica, hypotension, and hallucinations.  A century ago, PD was thought not to cause mental issues, but clearer understanding of the disease has led to important shifts in our assumptions about the causes and mechanism of PD, insights which are explored in our recent article.5  Far from being purely a motor (movement) disorder, patients with Parkinson’s show increased inflammation, signs of damage to the body’s metabolic system - which converts food into energy – and dysregulation of the tiny mitochondria which regulate energy within our cells.6 

Parkinson’s Disease is strongly linked to dementia. PD patients are almost six times as likely to develop dementia, and will display some of these symptoms: 

  • Loss of memory 
  • Problems with balance and movement 
  • Difficulties with words 
  • Becoming lost in a familiar environment 
  • Repeating the same questions or stories 
  • Taking longer to complete routine tasks 
  • Losing interest in daily activities 
  • Hallucinations, delusions, impulsivity, and paranoia 
  • Lack of empathy7 

Patients with PD have a much-increased likelihood of developing dementia, with prevalence rising to 90% among the oldest cohort.8, 9 

All forms of dementia, including PDD, seem to be connected to issues with the processing of the protein alpha-synuclein.  At present, eight genes are known to relate to PD, with mutations in at least one of these affecting the encoding of alpha-synuclein.  The role of this protein isn’t fully understood but, among other things, it helps regulate neurotransmitters, including dopamine (which governs movement, mood, and sleep) and acetylcholine (which affects memory and learning) as well as playing a role in DNA repair.  

At present, there is no cure for PD or any of the dementia-related diseases, but treatments are in development and recent research has yielded vital new insights. 

The Stages of Parkinson’s 

First articulated in 1967, the five stages of Parkinson’s Disease provide a terminology to describe the progression of the disease:10 

Stage One: mild symptoms which generally don’t interfere with daily life.  A one-sided tremor might be seen, and there could be changes in posture, gait, and facial expressions. 

Stage Two: worsening symptoms including tremor and rigidity on both sides of the body, or throughout the neck and torso.  Both walking and daily tasks become slower and more difficult. 

Stage Three: frequent loss of balance and falls are a hallmark of worsening motor symptoms.  The patient can live independently, with some restrictions on daily activities. 

Stage Four: symptoms are severely disabling.  The patient may need a cane or walker and will require significant help with daily life.  

Stage Five: leg stiffness makes it impossible to stand or walk.  The patient is confined to a wheelchair, or bedridden. 24/7 care is needed for every aspect of life. 

We would add a further stage to this classic structure: ‘Stage Six’ is dementia, which emerges gradually and in parallel with the other stages. 

There are lifestyle and nutrition strategies we can adopt to help slow down and help prevent Parkinson’s disease and other dementias. Diets such as the Mediterranean and MIND diets have been shown to be protective for brain health.11  Unfortunately, many people following Western diets don't prioritize the foods recommended in these diets. Moreover, busy lifestyles can make it challenging to maintain a consistent diet. However, food can be a powerful form of medicine when used strategically. 

One approach is through nutritional supplementation. RELEVATE, our brain health product, contains 17 clinically researched nutrients specifically chosen to support long-term brain health. These nutrients are based on those found in brain-healthy diets like the Mediterranean and MIND diets. 

RELEVATE serves as a bridge between the ideal intake of nutrients for brain health and the Standard American Diet (SAD).  To learn more and order, click here. 

If you decide you’d like to sign up for a subscription of RELEVATE, 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. 

We can see that Parkinson's is very strongly linked to dementia.  But which forms of dementia can arise with Parkinson's?  What are the signs that may arise with each form?  Tune in later this week as we take a deeper dive into Parkinson's and its link to various forms of dementias.  

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. Dementia Society of America® | Definitions. (n.d.). Retrieved April 21, 2024, from https://www.dementiasociety.org/definitions 
  2. Aarsland, D., Andersen, K., Larsen, J. P., Lolk, A., Nielsen, H., & Kragh-Sørensen, P. (2001). Risk of dementia in Parkinson’s disease: A community-based, prospective study. Neurology, 56(6), 730–736. https://doi.org/10.1212/WNL.56.6.730 
  3. Parkinson’s Disease – Symptoms, Diagnosis and Treatment. (n.d.). Retrieved April 21, 2024, from https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Parkinsons-Disease 
  4. Parkinson’s Disease | National Institute of Neurological Disorders and Stroke. (n.d.). Retrieved April 21, 2024, from https://www.ninds.nih.gov/health-information/disorders/parkinsons-disease 
  5. 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 
  6. Parkinson’s Disease- Dr Matthew Phillips: Fasting & Dietary Strategies as Parkinson’s Therapies - YouTube. (n.d.). Retrieved April 21, 2024, from https://www.youtube.com/watch?v=iBNNIIDBIYU 
  7. What Is Dementia? Symptoms, Types, and Diagnosis | National Institute on Aging. (n.d.). Retrieved April 21, 2024, from https://www.nia.nih.gov/health/alzheimers-and-dementia/what-dementia-symptoms-types-and-diagnosis 
  8. Buter, T. C., van den Hout, A., Matthews, F. E., Larsen, J. P., Brayne, C., & Aarsland, D. (2008). Dementia and survival in Parkinson disease: a 12-year population study. Neurology, 70(13), 1017–1022. https://doi.org/10.1212/01.WNL.0000306632.43729.24 
  9. Åström, D. O., Simonsen, J., Raket, L. L., Sgarbi, S., Hellsten, J., Hagell, P., Norlin, J. M., Kellerborg, K., Martinez-Martin, P., & Odin, P. (2022). High risk of developing dementia in Parkinson’s disease: a Swedish registry-based study. Scientific Reports 2022 12:1, 12(1), 1–7. https://doi.org/10.1038/s41598-022-21093-8 
  10. Hoehn, M. M., & Yahr, M. D. (1967). Parkinsonism: Onset, progression, and mortality. Neurology, 17(5), 427–442. https://doi.org/10.1212/WNL.17.5.427/ASSET/0830318B-9B53-41EE-AC84-904FE1BBD32D/ASSETS/WNL.17.5.427.FP.PNG 
  11. Agarwal, P. et al. Mind Diet Associated with Reduced Incidence and Delayed Progression of Parkinsonism in Old Age. J Nutr Heal. Aging 22, 1211–1215 (2018). 
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