The Difference Between Alzheimers And Parkinsons
Medically Reviewed by: Dr. BautistaUpdated on: September 3, 2021
Neurodegenerative disorders refer to a wide range of diseases and conditions that are characterized by progressive damage to the function or structure of nerves. While there are numerous known neurodegenerative disorders, the two most common and well-known are Alzheimers disease and Parkinsons disease.
Based on calculations, estimates suggest that about 6.2 million Americans will be living with Alzheimers disease in 2021. About one million Americans are estimated to be living with Parkinsons disease.
The two diseases are frequently grouped together, and while it may seem that Parkinsons falls into the category of diseases similar to Alzheimers due to similar clinical and neuropathologic features, Alzheimers and Parkinsons disease are uniquely different. They manifest differently, and they come with different forms of treatment to manage symptoms . Learn more about the difference between Alzheimers and Parkinsons below.
Mechanism Burden Scores Allow For Reproducible Subtyping Of Ad And Pd Patients
Using the data of 148 SNPs mapping to 15 common AD/PD disease mechanisms in 486 AD and 358 PD patients within our discovery cohorts, we developed an unsupervised machine learning approach to discover subgroups . This approach consisted of two basic steps: sparse autoencoding of the SNPs mapping to each of the 15 mechanisms, resulting into a profile of genetic burden scores consensus sparse non-negative matrix factorization to cluster patients and for identifying most discriminative mechanisms. Our method resulted in 4 subgroups in ADNI, PPMI as well as in a merger of ADNI and PPMI patients that were statistically stable and better discriminated than expected by pure chance details are described in the section and in the Supplementary Text . Interestingly, clusters found in the merged AD/PD cohort were all composed of a mixture of AD and PD patients . They were not identical to the ones identified in each disease individually, but showed a highly significant overlap in both cases -test). That means our clustering suggests the existence of certain commonalities between AD and PD patients on the level of SNP burden on specific mechanisms. We will discuss the question of disease relevance later.
Cluster 2 isamong other featuresstrongly associated with the genetic burden on IL1B, NLRP3, TP53,,,. Activation of IL1B by NLRP3 and TP53 play a role in the response of the immune system. Neuroinflammation is a common feature of AD and PD.
Strategy For Identifying Mechanism Based Ad/pd Subtypes
Before going into more detail, we briefly outline our general approach for identifying subtypes of sporadic AD and PD idiopathic patients : Following Tan et al. it is largely driven by the idea of a genetic sub-classification followed by a clinical, imaging based and biological characterization of patients in each cluster to test disease relevance.
Figure 1
Genetic commonalities between AD and PD can only be expected at the biological function level. Hence, the starting point of our work was a comprehensive mapping of the molecular disease landscape of AD and PD based on the scientific literature . The result was a set of 15 molecular mechanisms comprising 27 proteins that have been implicated in both diseases . We mapped 148 SNPs to these genes based on proximity as well as eQTL analysis, see details in Supplements. Using ADNI and PPMI as discovery cohorts , we calculated for each of the 15 molecular mechanism an aggregate burden score via sparse autoencoders and then used sparse non-negative matrix factorization to identify 4 distinct patient subgroups in AD and PD, see section. These subgroups were found independently in both diseases as well as in a merger of ADNI and PPMI patients .
Figure 2
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Symptoms Of Alzheimers Disease
The most common symptoms of Alzheimers disease are associated with memory loss. However, the way that memories are stored and recalled is distinct in people with Alzheimers than other forms of dementia. Patients with this disease usually have strong recollections of deeply seated memories.
However, they have trouble regurgitating information that they learned recently. Thats because Alzheimers changes the regions of the brain that are associated with learning.
Some of the symptoms of Alzheimers disease include:
- Trouble remembering new information
- Confusion about time, places and events
- Suspicions toward loved ones and caregivers
- Difficulty speaking, walking or swallowing
Alzheimers disease presents itself in different stages. Symptoms may vary, and the stages dont always correspond exactly with these, but understanding them may help you identify the condition in yourself or a loved one.
The stages of Alzheimers disease include:
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Clinical And Neuropathological Differences Between Parkinson’s Disease Parkinson’s Disease Dementia And Dementia With Lewy Bodies Current Issues And Future Directions
Institute of Neuroscience, Campus for Ageing and Vitality, Newcastle University, Newcastle-upon-Tyne, UK
First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
Biomedical Research Foundation of the Academy of Athens, Athens, Greece
Institute of Neuroscience, Campus for Ageing and Vitality, Newcastle University, Newcastle-upon-Tyne, UK
First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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Is Dementia A Symptom Of Both
One of the biggest similarities between PD and LBD is dementia. Some studies have found that approximately 78 percent of PD patients will eventually develop dementia.4 More specifically, almost half of Parkinsons patients will develop a certain type of dementia called Parkinsons Dementia, usually 10-15 years after their initial PD diagnosis.3 People with Parkinsons Dementia commonly experience poor memory and concentration, slowed thinking, confusion, depression, emotional changes, delusions, and visual hallucinations.
Parkinsons dementia is different than LBD, mainly in which symptoms occur first . Patients with Parkinsons Dementia will first show Parkinsons motor symptoms, followed by dementia many years after diagnosis. Conversely, LBD patients will first show dementia symptoms and may show motor symptoms later.3
The Effects Of Alzheimers On The Brain
Damage to the brain begins years before symptoms appear. Abnormal protein deposits form plaques and tangles in the brain of someone with Alzheimers disease. Connections between cells are lost, and they begin to die. In advanced cases, the brain shows significant shrinkage.
Its impossible to diagnose Alzheimers with complete accuracy while a person is alive. The diagnosis can only be confirmed when the brain is examined under a microscope during an autopsy. However, specialists are able to make the correct diagnosis up to 90 percent of the time.
The symptoms of Alzheimers and dementia can overlap, but there can be some differences.
Both conditions can cause:
- behavioral changes
- difficulty speaking, swallowing, or walking in advanced stages of the disease
Some types of dementia will share some of these symptoms, but they include or exclude other symptoms that can help make a differential diagnosis. Lewy body dementia , for example, has many of the same later symptoms as Alzheimers. However, people with LBD but are more likely to experience initial symptoms such as visual hallucinations, difficulties with balance, and sleep disturbances.
People with dementia due to Parkinsons or Huntingtons disease are more likely to experience involuntary movement in the early stages of the disease.
Treatment for dementia will depend on the exact cause and type of dementia, but many treatments for dementia and Alzheimers will overlap.
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Lrrk2 Phosphorylates Tau Protein
Parkinsons patients can develop tangles of the tau protein as a result of a mutated enzyme called LRRK2, the researchers say.
From conducting a series of mammalian studies, the researchers discovered that standard LRRK2 adds groups of phosphate to tau protein, while mutated LRRK2 adds significantly more phosphates to tau protein.
Using these findings, the research team were able to uncover two sites on the tau protein T149 and T153 where the mutated LRRK2 was able to add phosphate groups, which they linked to tangle formations.
The researchers then went on to test their findings on human brain tissue. From this, they discovered that the two sites previously identified on the tau protein that were targeted by LRRK2, were altered the same way in human tissue with LRRK2 mutation.
When testing this finding on human brain tissue that was affected by Alzheimers disease, and other neurodegenerative diseases that form tangles, they found these alterations were the same.
Explaining their findings, the researchers say:
Our data, in aggregate, demonstrate that LRRK2 directly phosphorylates tau at T149 and T153 in vitro and the ability of LRRK2 to phosphorylate tau at these sites may underlie its ability to promote tauopathy in our novel mouse model.
Our current in vivo studies are the first of their kind and provide compelling evidence that LRRK2 and tau interact in a disease-relevant manner.
What Is Parkinsons Disease
Parkinsons disease was described by James Parkinson nearly 100 years before Dr. Alois Alzheimer described the dementia later named Alzheimers disease . Called the shaking palsy by Parkinson, PD is diagnosed when a person shows at least two of these three symptoms: slowed movements , muscle rigidity, and tremor . We recognize many other associated signs of PD, including expressionless face, quiet speech, cramped handwriting, shuffling gait, trouble getting out of a chair, and difficulty swallowing. Many of the symptoms of idiopathic Parkinson’s disease result when certain nerve cells that produce dopamine in the brain begin to malfunction and die.
Most cases are called idiopathic, meaning the cause remains unknown, although a small number of cases are linked with poisoning , head trauma, more complex PD-like neurological disorders , or reversible toxic medication effects ,
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What Causes Lewy Body Dementia
The causes of LBD are not yet well understood, but research is ongoing in this area. There are probably multiple factors involved, including genetic and environmental risk factors that combine with natural aging processes to make someone susceptible to LBD.
For more information, visit www.lbda.org.
Modified with permission from the Lewy Body Dementia Association
To learn more about motor symptoms related to Parkinsons, visit here.
To learn more about non-motor symptoms related to Parkinsons, visit here.
Parkinsons Doesnt Always Cause Dementia
While cognitive decline is common in both Alzheimers and Parkinsons, it is less likely to occur in Parkinsons patients. According to studies, only half of those with Parkinsons develop cognitive difficulties. This can range from mild forgetfulness to full-blown dementia.
When dementia does manifest itself with Parkinson, it occurs in the subcortical area of the brain. Alzheimers dementia occurs in the cortical area of the brain. As a result of this, the clinical symptoms of these two dementias can be somewhat different.
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Early Signs And Symptoms Are Different
Parkinsons disease generally begins as a movement disorder. Early signs and symptoms include:2
- Tremor, which often begins in the hand or fingers
- Slowed movement, which may include foot dragging
- Rigidity
- Slowed automatic movements such as blinking, smiling, and swinging your arms when you walk
Alzheimers disease generally begins as noticeable memory loss. Early signs and symptoms include:3,4
- Trouble remembering familiar words
- Challenges performing everyday tasks such as balancing a checkbook
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Number Of People Affected
Parkinsons disease is thought to affect about 2 percent of Americans over 65. Of those, about 50 to 80 percent will go on to develop Parkinsons-related dementia.1 The Parkinsons Foundation estimates that nearly 1 million Americans will be living with Parkinsons by 2020. The disease affects 1.5 times more men than women.7
Approximately 5.8 million Americans are currently living with Alzheimers disease. That number is expected to increase to 14 million by 2050.8 There is little difference between numbers of men and women who develop Alzheimers, but there are more women with the disease, because women tend to live longer than men.3
Where To Get Help
- Your local community health service
- Your local council
- National Dementia Helpline Dementia Australia Tel. 1800 100 500
- Aged Care Assessment Services Tel. 1300 135 090
- My Aged Care Tel. 1800 200 422
- Cognitive Dementia and Memory Service clinics Tel. 1300 135 090
- Carers Victoria Tel. 1800 242 636
- Commonwealth Respite and Carelink Centres Tel 1800 052 222
- Dementia Behaviour Management Advisory Service Tel. 1800 699 799 for 24-hour telephone advice for carers and care workers
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Differences Between Delirium Dementia Alzheimer’s And Parkinson’s
Your brain doesnt finish developing until your mid-to-late 20s. Is it all downhill from there? Neuroscientists are discovering that you can continue to rewire your brain to encourage growth and prevent your brain cells from dying, but everyone experiences age-related cognitive decline.
Its often lumped into an umbrella category of mental slowdown that happens as you get older.
However, there are a few different brain diseases that affect aging adults. Heres how to understand the difference between delirium, dementia, Alzheimers and Parkinsons.
Difference Between Alzheimers Disease And Parkinsons Disease
Categorized under Health | Difference Between Alzheimers Disease and Parkinsons Disease
Alzheimers Disease vs Parkinsons Disease
Alzheimers disease and Parkinsons disease are both degenerative brain diseases. However, they differ in their symptoms, biological and physical manifestations , causes, and treatment.
Alzheimers disease is a form of dementia thats more directly related with a persons age. The primary pathophysiology of Alzheimers disease observes nerve cell deterioration which is demonstrated as an increased loss of coherence and a progressive loss of ability to conduct normal activities of daily living.
From a biochemical perspective, Alzheimers disease is caused by the lack of acetylcholine, which is a neurotransmitter in both the peripheral nervous system and central nervous system . Anatomically, portions of the brain such as the temporal lobe, parietal lobe, and frontal cortex are affected.
There is little known treatment for Alzheimers disease, though research indicates that acetylcholinesterase inhibitors can slow the progression of the disease once a positive diagnosis has been established. Studies for prevention suggest that performing simple mental exercises such as reading and maintaining regular mentally stimulating activity reduces the chance of acquiring the disease.
Treatment for Parkinsons disease involves dopamine precursors and agonists to increase the presence of dopamine.
Summary:
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Acknowledgments And Conflict Of Interest Disclosure
Data in this manuscript are original and were generated for the purpose of this study. Photomicrographs were taken from tissue provided by the Newcastle Brain Tissue Resource, which is funded in part by a grant from the UK Medical Research Council , by Brains for Dementia research, a joint venture between Alzheimer’s Society and Alzheimer’s Research UK and by the NIHR Newcastle Biomedical Research Centre awarded to the Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University. DLB research is supported by NIHR Newcastle Biomedical Research Centre in Ageing and Long-Term Conditions. LW is funded by the Alzheimer’s Society. The authors have no conflicts of interest to declare.
Living With Parkinson Disease
These measures can help you live well with Parkinson disease:
- An exercise routine can help keep muscles flexible and mobile. Exercise also releases natural brain chemicals that can improve emotional well-being.
- High protein meals can benefit your brain chemistry
- Physical, occupational, and speech therapy can help your ability to care for yourself and communicate with others
- If you or your family has questions about Parkinson disease, want information about treatment, or need to find support, you can contact the American Parkinson Disease Association.
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Don’t Smoke Lessen Alcohol Intake & Do Not Take Drugs
Even if you don’t drink a lot, alcohol has a cumulative effect on your brain. One blackout after a drinking binge can induce life long memory loss. Over time, smaller amounts of alcohol will lead to blackouts and soon you’ll have a ton of lost time even though you barely drank one bottle of beer.
Smoking negatively affects memory by reducing the amount of oxygen that reaches the brain while repeated drug use kills your neurons and the rushes of dopamine reinforce drug dependence.
What Is Alzheimers Disease
Alzheimers is named after Dr. Alois Alzheimer, a German neurologist who first discovered the cognitive function disease. Alzheimers disease is a neurologic disorder that is characterized by damage to the brain cells and actual brain shrinkage, or atrophy. Alzheimers disease is the leading cause of dementia, a generic term for behavioral and cognitive decline that may affect your basic ability to function as an AD patient.
While research still does not know the exact cause of Alzheimers disease, the basic mechanism involves dysfunction in brain proteins. This disrupts normal function in brain cells for an AD patient, known as neurons. The brain disorder results in damage to the neurons, a loss of connection between neurons, and eventually dead brain cells for an Alzheimers patient. This process typically starts in areas of the brain involved with memory, but this can start years prior to any noticeable cognitive symptoms. The neuronal atrophy eventually spreads to other regions of the brain, leading to increased brain shrinkage and severe cognitive issues.
There is currently no known cure for an Alzheimers patient, but medication can help to manage symptoms, maximize function, and slow the cognitive impairment diseases progress, enough to support your independence for some time.
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