What is the difference between Alzheimer's and Parkinson's disease?

Alzheimer’s disease and Parkinson's disease, also known as “Parkinsonism” can be collectively termed as neurodegenerative disorders or precisely neurological disorders. 

Learning The Basic Difference Between Alzheimer’s Disease and Parkinson's Disease 

Alzheimer's disease usually begins in the hippocampus, where new memories are formed. 

Older memories are not so affected, which is why a person can remember the storytelling session with the grandma but has forgotten what he just ate a few hours ago.  In elderly people, this stage is often called Mild Cognitive Impairment (MCI). It’s a classic example of progressing disease that is characterized by dementia. 

It’s mostly the nerve cells in the brain that start to be destroyed: these are the connective branches that carry the signals, which are our thoughts, memories, and feelings. 

When memories start to disappear, often, the emotions around that memory remain intact. This is because the amygdala, where emotions happen, doesn’t degrade until after the hippocampus.

As the disease becomes mild or early Alzheimer’s, these symptoms get worse. Learning new information becomes increasingly difficult.

As the damage spreads through the brain, the other lobes of the brain get affected. As time passes by, the cortex starts to grow thinner, and the volume of the overall brain decreases. Different lobes get affected to show different symptoms. 

A few noticeable attributes of this disease are from losing semantic memory to having no spatial awareness about special aspects of life. 

Apart from this, there are different known stages of Alzheimer’s: 

1. Early-onset Alzheimer’s 
2. Mild-onset Alzheimer’s 
3. Moderate-onset Alzheimer’s 

On the contrary, Parkinson’s disease is a degenerative condition of the substantia nigra in the basal ganglia, which is on top of the brain stem but lie deep in the center and at the bottom of the brain. The brain cells produce the brain hormone called dopamine which is considered mandatory to coordinate the different body movements without any restriction. 

In general, muscle movements become jerky without the function of the basal ganglia, and there arises a problem in adjusting the body posture according to the latest position. 

As a result, the muscle movements are slowed and show a decrease in rigidity, resting tremor, and instability with regard to posture.

Risk Factors Associated with Alzheimer's Disease

• Age - the disorder is more likely in older adults, and a greater proportion of over-85-year-olds have it than in those over 65
• Family history (inheritance of genes) - having Alzheimer's in the family is associated with higher risk. This is the second biggest risk factor after age.
• Having a certain gene (the apolipoprotein E or APOE gene) puts a person, depending on their specific genetics, at three to eight times more risk than a person without the gene.6 Numerous other genes have been found to be associated with Alzheimer's disease, even recently.
• Factors that increase blood vessel (vascular) risk - include diabetes, high cholesterol, and high blood pressure. (These also increase the risk of stroke, which itself can lead to another type of dementia.)
• Low educational and occupational attainment.
• Prior head injury. (While a traumatic brain injury does not necessarily lead to Alzheimer's, some research links have been drawn, with increasing risk tied to the severity of trauma history.)
• Sleep disturbances (the breathing problem sleep apnea).

Risk Factors Associated with Parkinson's Disease

• Age - advancing age is one of the critical factors in its development. Usually, age above 60 is a major risk factor. 
• Gender - Men are more prone to the development of Parkinson’s disease when compared to women. 
• Family history - Patient’s with positive family history and first-degree relatives showing the disease is most likely to have it. Usually, affected parents and siblings are able to transfer the disease. 
• Genetic and environmental factors: Certain chemicals like pesticides and insecticides are a great contributor. Other chemical agents that are potential risk factors are metals, detergents, solvents, etc. 
• Head Trauma: Prior head trauma can predispose one to such disease. 

How do Alzheimer’s and Parkinson’s Disease Develop? 

Alzheimer's is primarily caused by inherited specific gene mutations - the genes involved are called APOE3 and APOE4. If you have both, your likelihood of Alzheimer's is greater. Some of the commercially available testing kits allow you to take samples at home, mail them in, and get results. If you test positive for either of these genes, you should consult a qualified neurologist - please don't try to diagnose yourself with the nonsense being spread about this disease on the internet!

Current research suggests two principal pathways for the damage to nerve cells and cognition that results from Alzheimer's. 

The first is the development of fatty deposits referred to as 'plaques' that form on the cell bodies of neurons and disrupt their proper function. The second is a protein called Tau, which forms tendrils that grow around and within synapses (the junctions between neurons where they communicate with each other electrically and/or chemically). The effect of Tau is to disrupt the signaling between the nerve cells. 

The exact cause of Parkinson’s disease is unknown. This disease is a clump of misfolded proteins within neurons called the Lewy bodies. Alpha-synuclein is the characteristic misfolded protein, and these molecules form small repeated units called oligomers. These Lewy bodies are toxic to nerve cells and are the major reason why Parkinson’s dementia arises. Another reason for the disease is the disrupted mitochondria. 

Diagnostic Features 

10 Major Alzheimer's Disease Symptoms

1. Memory failure
2. Losing track of dates
3. Taking very long to complete daily tasks
4. Misplacing things 
5. Difficulty learning and remembering new things 
6. Mood and personality changes 
7. Anxiety and depression 

Dementia Related Symptoms and Alzheimer’s Disease - Are These Neurological Illness Similar? 

Dementia is a syndrome or a group of symptoms—memory impairment, decreased judgment, reasoning, or ability to learn new things, etc—that can be caused in a variety of ways. 

Developing dementia can be caused by diseases that affect nerve cells in the brain (multiple sclerosis, Alzheimer’s, Parkinson’s). Dementia can also be caused by brain tumors, strokes (vascular disease), head injuries, decreased nutrition, infection (AIDs, Creuzfeldt-Jakob disease), and other diseases. 

Alzheimer’s disease is one form of dementia. Alzheimer’s disease has specific signs and symptoms that define it as a specific disease process, as does Lewy Body Dementia, cortico-basal, frontotemporal, etc.

 The other dementias are not as prevalent but are still important clinically and are caused by other mechanisms. Lewy body dementia is similar but involves a protein called alpha-synuclein instead of amyloid beta, which aggregates to form ‘Lewy bodies.’ These are also present in Parkinson’s disease.When any two or more types of dementia are present at the same time, the individual is considered to have mixed dementia (due to other medical conditions).

10 Major Parkinson’s Disease Symptoms

1. Depression 
2. Parkinson’s disease dementia
3. Anxiety 
4. Dizziness 
5. Fainting 
6. Cognitive difficulties
7. Muscle weakness 
8. Upper respiratory tract obstruction
9. Constipation 
10. Blepharospasm
11. Excessive Salivation

Treatment For Alzheimer’s Disease 

Galantamine, rivastigmine, and donepezil are cholinesterase inhibitors are the drugs of choice in Alzheimer’s disease.  These drugs tackle major physical brain changes and help introduce motivation, reduce anxiety levels and enhance memory. Aducanumab is currently one of the most used medications for the disease. Before prescribing this medication, a PET scan is necessary. 

Other Alzheimer’s treatment regimens include the popular photobiomodulation therapy.  Photobiomodulation therapy uses infrared light stimulation, brainwave biofeedback, and functional medicine to eliminate the root causes of the ailment. 

Treatment For Parkinson’s Disease 

#1 - Medicational Treatment 

Parkinson’s disease is well-addressed by dopamine agonist drugs combined with anticholinergics; even in advanced stages, patients prefer being on the drugs, despite all kinds of complications like on-off phenomenon and levodopa-induced dyskinesia. 

Levodopa is the most common drug; this drug is the chemical precursor of dopamine. (Dopamine itself does not pass the blood-brain barrier, but levodopa does.) Levodopa is almost always combined with carbidopa; this drug does not impact Parkinson’s disease symptoms but helps reduce side effects of levodopa, particularly nausea, and aids in the absorption of levodopa.

While levodopa is the most common drug for Parkinson’s disease, there are many other options and many formulations of levodopa. There are many other drugs that are prescribed with levodopa-carbidopa complex, which include: 

• Enzyme Inhibitors (e.g., MAO-B inhibitors, COMT inhibitors) to increase the overall amount of produce dopamine. 
• Amantadine to reduce involuntary movements. 
• Anticholinergic drugs to reduce muscle rigidity 

#2 - Deep Brain Stimulation 

Surgical intervention is the only option that remains when stability is not achieved alone with the drugs. In such a therapy, electrodes are inserted in the targeted area of the brain, and brain activity is recorded during this step. An MRI is done prior to electrode insertion. The next step includes the insertion of an impulse generator battery to deliver electrical signals to the targeted area. The stimulation is meant to control bodily movements. 

#3 - Supplementary Therapy 

Supplemental therapy mainly includes the aspect of lifestyle modification. It allows early and better recovery. It is collectively corrected with 

• Physical and speech therapy 
• A healthy balanced diet 
• Regular exercise and workout 
• Yoga activities 
• Massage therapy. 

It’s No Brainer - How To Prevent Alzheimer’s and Parkinson’s Disease? 

#1 - Eat a healthy diet - lower in meat and fats and higher in vegetables, grains, and fish - the Mediterranean diet is often recommended

#2 - Stay physically active - either walking or any other kind of exercise that raises your heart rate for at least an hour or so a day

#3 - Stay intellectually engaged - reading, writing, talking with other people

#4 - Stay socially engaged - humans evolved to live together and nothing lights up the brain as much as social interaction

What is The Difference Between Alzheimer’s and Parkinson's Disease?