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Alzheimer's vs. Parkinson's

Alzheimer's and Parkinson's are both neurodegenerative diseases that affect motor function and communication, prevalent in people over the age of 65. While both diseases currently have no cure, there are different options to treat symptoms. The brain is incredibly complex, which is why scientists are now only touching the surface to comprehend the "why's" of the two diseases.


Alzheimer's is a neurodegenerative disease that destroys neurons. The deposit of protein called beta-amyloid builds an abnormal plaque in the space between neurons. Twisted fibres called tau also build up in the cells. The Tangles and plaque both cause the lack of connection between neurons, which are thought to block the communication nerve cells and disrupt cellular processes. This can possibly result in nerve cell death.

Image is courtesy of the National Institute On Aging.

The damage in the brain occurs in the hippocampus as well as the entorhinal cortex—parts of the brain that are essential for forming memories. The cause of Alzheimer's is due to a combination of factors; genetic, environmental and lifestyle factors are all possible causes to this disease.

A common treatment for this disease is Cholinesterase inhibitors that prevent the breakdown of acetylcholine (neurotransmitter). Examples of medications include Aricept and Exelon.


Parkinson's is a neurodegenerative disease that impact motor function, leading to symptoms such as shaking, stiffness, balance and coordination. Within Parkinson’s, there's a deficiency of dopamine, which results in poor nerve communication. This therefore causes movement problems. Dopamine is a neurotransmitter that helps regulate body movements and mood.

Those with Parkinson's also lose nerve endings for norepinephrine, a hormone that regulates the sympathetic nervous system and autonomic functions of the body, including heart rate and blood pressure. This is why symptoms of Parkinson's disease include fatigue, decreased movement of food in the digestive tract, and irregular blood pressure.

Due to a build up of lewy body clumps made from misfolded synuclein proteins, the basal ganglia and the substantia nigra degenerate. Those parts of the brain are essential for releasing neurotransmitters like dopamine.

There are a few options for Treatment of Parkinson's:

Dopamine supplements

  • Levodopa is a drug that can replenish the brain's deficient supply of dopamine.

MAO-B Inhibitors

  • Slows down the enzyme that breaks down dopamine.

Deep Brain Stimulation

  • Surgical procedure that implants an electrode into the brain connected to an electrical device implanted in the chest by wires.

  • Electrical impulses from electrode interrupts irregular signals in brain.

  • Can help reduce motor symptoms such as tremors, slowness, rigidity.


NIH. (2017). What Is Alzheimer’s Disease? National Institute on Aging. https://www.nia.nih.gov/health/what-alzheimers-disease#:~:text=Alzheimer’s%20disease%20is%20an%20irreversible,appear%20in%20their%20mid%2D60s.

What is Alzheimer’s? (2021). Alzheimer’s Disease and Dementia. https://www.alz.org/alzheimers-dementia/what-is-alzheimers

NIH. (2019). Alzheimer’s Disease Fact Sheet. National Institute on Aging. https://www.nia.nih.gov/health/alzheimers-disease-fact-sheet

NIH. (2018). How Is Alzheimer’s Disease Treated? National Institute on Aging. https://www.nia.nih.gov/health/how-alzheimers-disease-treated

NIH. (2017). Parkinson’s Disease. National Institute on Aging. https://www.nia.nih.gov/health/parkinsons-disease#:~:text=Parkinson’s%20disease%20is%20a%20brain,have%20difficulty%20walking%20and%20talking.

NIH. (2017). Parkinson’s Disease. National Institute on Aging. https://www.nia.nih.gov/health/parkinsons-disease

Gonzalez-Usigli, H. A. (2020, September). Parkinson Disease. Merck Manuals Consumer Version. https://www.merckmanuals.com/en-ca/home/brain,-spinal-cord,-and-nerve-disorders/movement-disorders/parkinson-disease-pd

Article Contributors: Ashley Chen, Edie Whittington

Article Editor: Sherilyn Wen