Comparing Alzheimer’s, ALS, MS, and Parkinson’s


I recently realized that I did not fully understand the differences, or the similarities, that some of the most common neurological diseases shared. I will share in this post some basic comparisons of Alzheimer’s, ALS, MS, and Parkinson’s. Find out what you need to know about causes, treatments, and symptoms, of these neurological diseases.


The typical age onset of Alzheimer’s is about 65 years. In the US, about 500,000 new cases per year get diagnosed. The region of the brain affected is the hippocampus. This part of the brain forms and stores memories. The primary symptoms are dementia, impaired cognitive function, and behavioral and psychiatric issues.

There is not one single cause established for contracting Alzheimer’s. It seems to be a combination of the following: genetic predisposition, lifestyle and environmental factors. These affect the brain in ways that lead to shrinkage, cell death, plaques, and tangles. Past head trauma may be linked to future Alzheimer’s diagnosis as well.

More recently the connection between infectious pathogens as the root cause has come to the forefront of new research.

Amyotrophic Lateral Sclerosis

More commonly known as ALS or Lou Gehrig’s disease, the onset of this disease is usually around age 55, but can come on as early as 40 or as late as 70. About 30,000 new cases each year are diagnosed in the US. There are two different types of ALS, sporadic and familial. Sporadic, is the most common form of the disease. It may affect anyone, anywhere. Familial ALS means the disease is inherited. Familial ALS accounts for 5 to 10 percent of all cases in the U.S.

This disease affects the motor neurons of the brain and the spinal cord. “A” means no. “Myo” refers to muscle, and “Trophic” means nourishment – “No muscle nourishment.” When a muscle has no nourishment, it “atrophies” or wastes away. “Lateral” identifies the areas in a person’s spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates, it leads to scarring or hardening (“sclerosis”) in the region.

The primary symptoms are difficulty walking, weakness in limbs, slurring of speech, trouble swallowing, muscle cramps and twitching.

Because the cause is so allusive, there is very little that can be done for prevention. Some studies point to gut health, as well as the consumption of poor quality or unhealthy meat as links to the cause. Lyme disease also gets connected to ALS sometimes, but there is no hard science to support that connection at this time.

Multiple Sclerosis

Usually referred to as MS, this disease onset is usually around 34 years of age, but can be diagnosed as early as 20 or as late as 50. About 10,000 new cases are diagnosed each year in the US.

This disease affects the myelin sheath of neurons. This damage disrupts the ability of parts of the nervous system to communicate, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. MS takes several forms, with new symptoms either occurring in isolated attacks (relapsing forms) or building up over time (progressive forms).

The primary symptoms are fatigue, walking (gait) difficulties, numbness, tingling, spasticity, weakness, vision problems, dizziness and vertigo.

While the cause is not clear, the underlying mechanism is thought to be either destruction by the immune system or failure of the myelin-producing cells. Proposed causes for this include genetics and environmental factors such as being triggered by a viral infection.

Parkinson’s Disease

The average onset is about 60 years of age, and 60,000 people are diagnosed each year. The disease affects the substantia nigra, which is a structure, located in the midbrain that plays an important role in dopamine synthesis. Parkinson’s symptoms are primarily caused by low and falling dopamine levels. Dopamine-generating cells, known as dopaminergic neurons (types of nerve cells) in the substantia nigra part of the brain have died.

The primary symptoms are shaking or tremor at rest, slowness of movement, stiffness or rigidity of the arms and legs, trouble with balance, and postural instability.

In addition to movement-related (“motor”) symptoms, Parkinson’s symptoms may be unrelated to movement (“non-motor”). People with PD are often more impacted by their non-motor symptoms than motor symptoms. Examples of non-motor symptoms include: apathy, depression, constipation, sleep behavior disorders, loss of sense of smell and cognitive impairment.

Environmental causes like long-term exposure to chemicals, toxins, heavy metals, pesticides etc. are most likely at the root cause of the disease. Family history and suffering from a TBI (traumatic brain injury) earlier in life are also linked to the increase chances of having Parkinson’s.

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