Parkinson’s disease (PD) is a neurodegenerative disorder that affects a part of the brain called the substantia nigra. Multiple sclerosis (MS) is an immune-mediated disease in which the immune system attacks the central nervous system (CNS), including the spine, brain, and optic nerves.

Both PD and MS are lifelong diseases that can affect how a person controls their movements. However, they are distinct conditions with different causes, diagnostic criteria, and treatments.

Rarely, PD and MS may occur together. This has caused some researchers to investigate whether there is a link between the two conditions.

This article discusses the similarities and differences between PD and MS. We also describe how doctors diagnose and treat PD and MS.

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Multiple sclerosis (MS) can cause symptoms that resemble those of several other conditions, including:

Doctors make a diagnosis of MS based on:

  • a person’s medical history
  • a physical examination
  • diagnostic tests

According to the National Multiple Sclerosis Society (NMSS), doctors typically use the following combination of tests to diagnose MS:

  • Neurological examination: This will include testing the following:
    • balance
    • strength
    • walking
    • movement
    • eyesight
    • hearing
    • swallowing
  • Extensive review of medical history: This will include an assessment of:
    • symptoms
    • medical history
    • family history
  • Blood tests: These will help rule out other possible causes of the symptoms, such as vitamin deficiencies and other underlying medical conditions.
  • MRI scans: MRI scans help identify inflammation, demyelination, and MS lesions.
  • Spinal fluid analysis: A spinal fluid analysis helps detect damage to the protective myelin sheath that surrounds nerve fibers in the CNS.

The NMSS further notes that, in order for a doctor to diagnose MS, they must:

  • rule out any other possible medical conditions
  • find evidence of damage to at least two different areas of the CNS
  • find evidence that the CNS damage occurred on two separate occasions

Doctors typically make a diagnosis of PD using a physical examination.

Early diagnosis is often difficult. However, trained or well-experienced neurologists can sometimes make a diagnosis based on early signs and symptoms.

In order for a doctor to diagnose PD, a person must have experienced at least two of the following four symptoms:

According to 2016 research, both MS and PD can affect a person’s physical and cognitive functioning. These conditions typically have more severe physical effects than cognitive effects, particularly during the early stages of the diseases.

Some of the symptoms of MS and PD are similar. The following are some potential symptoms that are common in both conditions, according to the NMSS and the American Parkinson Disease Association (APDA):

  • fatigue
  • pain
  • difficulty walking
  • urinary issues
  • bowel issues
  • sexual issues
  • lightheadedness
  • changes in cognitive functioning
  • depression or anxiety
  • dizziness
  • balance problems
  • sleeping problems
  • muscle spasticity
  • muscle pain
  • difficulty speaking clearly
  • difficulty swallowing

Finally, neither condition by itself is fatal, but both can lead to further health complications.

Despite several similarities in symptoms, MS and PD are two distinct conditions. Some differences between the two conditions are outlined below.

Age of onset

One area in which MS and PD differ is the typical age of onset. According to 2016 research, doctors typically diagnose MS in people ages 20–40, while the typical age of diagnosis for PD is over 60 years old.

Causes

Multiple sclerosis and PD have different causes.

PD is a neurodegenerative disease that occurs due to the dysfunction of cells in the brain’s basal ganglia and the brain’s altered response to dopamine. MS is an inflammatory disease that causes the demyelination of nerves in the CNS, which is what causes the symptoms of MS.

Researchers are not sure what causes MS to occur. However, the following factors may play a role in the development of the inflammation behind the condition:

  • genetics
  • environment
  • infectious agents
  • immunological factors

Researchers believe that PD develops as a result of genetic factors, environmental factors, or a combination of the two.

Treatment and outlook

The treatment and outlook for MS and PD vary.

The treatment for MS focuses on slowing the progression of the disease. In some cases, treatment may help prevent flares from occurring or shorten how long they last.

Treatment for PD focuses on managing the symptoms. There is currently no way to stop or reverse the disease.

Researchers have recently begun investigating a possible connection between MS and PD.

In a 2020 case study, researchers note a potential link between MS and PD. They find that people living with MS who have a mutated GBA1 gene may have a higher risk of developing PD. However, it is not clear why this is the case.

According to an earlier 2014 literature review, MS may affect a person’s brain tissue and brain structure in a way that triggers the development of PD. Nonetheless, this connection is unlikely to be strong. The study authors note that there are only 34 reported cases of coexisting MS and PD, indicating that it is rare for people to develop both conditions.

More research is necessary to establish any firm connection between MS and PD.

Doctors treat both MS and PD using a combination of medications and therapies.

Treating MS

Doctors typically prescribe disease-modifying drugs for the treatment of MS. These medications can help:

  • slow disease progression
  • prevent relapses
  • prevent new disease activity

Disease-modifying medications are available in the following forms:

  • oral medications
  • injectable medications
  • infusions

A treatment plan for MS may also include therapies to help a person maintain or regain physical functions.

Learn more about treatment for MS here.

Treating PD

There are several ways to treat PD.

No treatment can reverse the effects of PD. However, the following treatments can help manage the symptoms:

Learn more about treatment for PD here.

While there is currently no cure for MS or PD, treatments can help slow the progression of these diseases.

Neither MS nor PD is fatal, but both conditions can cause complications that may prove fatal. Following a recommended treatment plan can help prevent disease progression and reduce the risk of complications.

Outlook for MS

The exact prognosis for a person living with MS can vary greatly. Some people will experience only sporadic symptom flare-ups, while others will experience more frequent symptom flare-ups.

According to the Multiple Sclerosis Trust, some factors that can indicate a more favorable outlook include:

  • being younger than 40 years of age at diagnosis
  • being female
  • experiencing mainly sensory symptoms, such as tingling or numbness
  • experiencing long intervals between relapses
  • experiencing infrequent relapses during the first few years of diagnosis
  • experiencing a complete recovery following relapses

Most people living with MS can expect a relatively normal lifespan.

Outlook for PD

People living with PD may expect a relatively normal life span. Treatments can help slow the progression of the disease and provide some symptom relief. However, no treatment can reverse the disease.

There are some signs and symptoms that are common to both MS and PD. However, the diagnostic criteria and treatment options differ in each case.

In rare cases, a person may develop both MS and PD. However, further research is necessary to confirm a possible link between the two conditions.

Treatment can help prevent both MS and PD from worsening. It can also help reduce the risk of complications. A person should work closely with their doctor to develop an appropriate treatment plan.