Determining Symptoms: Is it Parkinson’s Disease or Aging?

Is it a Parkinson’s symptom or a symptom of aging?

As people age, they encounter new symptoms which may interfere with quality of life. The same is true for people with Parkinson’s disease (PD). The tricky thing is that there are many similar symptoms between the two causes!

Often people with PD are left wondering: “Are my experiences attributed to Parkinson’s disease or is it a result of the natural aging process?” Even more importantly, people ask: “How do I treat these symptoms and improve my quality of life?”

Here are some important concepts to help sort out this confusing topic:

1. The common symptoms of Parkinson’s disease, and why these symptoms occur
2. The common symptoms of aging, and why these symptoms occur
3. How to approach a new symptom if you have Parkinson’s disease
4. Symptoms that are specific to PD
5. Symptoms that overlap between PD and aging, and how the symptoms can differ

Symptoms of Parkinson’s Disease

Symptoms of PD can broadly be divided into two large categories – motor and non-motor symptoms.

Motor symptoms are those that affect movement and include:

• rest tremor
• stiffness
• slowness
• difficulty with balance
• shuffling gait
• expressionless face
• and others

Non-motor symptoms are ones that do not affect movement and include:

• pain
• cognitive disorders
• sleep disorders
• constipation
• urinary frequency
• pain syndromes
• and others

It is important to point out that the major difference between a symptom caused by PD and a symptom caused by aging, is the cause behind the symptom. PD symptoms are caused by death of nerve cells, with the prevailing hypothesis that the death is due to the abnormal accumulation of the protein alpha-synuclein in clumps called Lewy bodies.

Because different parts of the brain control different functions, the same lesion in one part of the brain will cause one set of symptoms and in another part of the brain will cause a different set of symptoms.

When Lewy bodies are present in the brainstem, body functions that are controlled by the brainstem will be affected, causing symptoms such as constipation and sleep disorders. When Lewy bodies affect the substantia nigra, located in the midbrain portion of the brainstem, motor symptoms of PD will emerge. When Lewy bodies affect the cortex or the ‘thinking part’ of the brain, cognitive symptoms become apparent.

Symptoms associated with aging

Symptoms of aging are not caused by deposition of alpha-synuclein into neurons.

There are two main reasons why symptoms occur as people age:

1. They are due to a disease or medical condition that occurs commonly as people age (such as cancer, diabetes, etc.)
2. They are due to the general wear and tear of aging itself.

As we learn more and more about the human body, doctors are less inclined to call a symptom “normal aging”. Even if a symptom is very common in the aging population, it could still be due to a disease state that needs to be identified and could potentially be treated.

Likewise, if symptoms are due to processes that occur with natural aging that are not due to a disease state, those symptoms may be able to be treated and improved. To refer to a symptom as “normal” may imply that there are no treatment options, and the symptom must simply be tolerated.

The tricky overlap of symptoms in Parkinson’s disease and aging

Navigating New Symptoms with PD

If you have a symptom that is common between aging and PD, it may not be possible to determine if the problem is caused by one or the other, and it may very well be caused by both.

It is important to notify your doctors about the symptom for evaluation, and to take these steps:

1. Gather as much information about the symptom as you can (how often is it occurring, does something trigger the symptom, etc.) to share with your doctor. The APDA Symptom Tracker app can help.
2. Have a thorough medical work-up to determine if there are any reversible causes of the symptom.
3. Seek treatment for the symptom. Do not accept the answer “It must be due to your PD, so there is nothing to be done”. This is an unacceptable answer as many motor and non-motor symptoms of PD can be treated. The symptom(s) may not be resolved completely but could be improved. Motor and non-motor symptoms of aging can also be treated even if they are due to normal wear and tear.

Symptoms that occur in PD that typically do not occur in aging

Let’s first look at the symptoms that are specific to PD (but not typically attributed to general aging), and then we will walk through the symptoms that overlap.

It is important to point out that there are certain symptoms of PD that are not common in aging. Some of the motor symptoms of PD are distinct to PD and a neurologist is usually able to distinguish them from changes due to regular aging.

These PD Symptoms include:

• Rest tremor: Rest tremor is highly characteristic of PD and is not seen in other conditions. A rest tremor is a rhythmic shaking of a body part that occurs when the body part is not being held against gravity and is not moving. Rest tremors occur for example, when the hands are resting in the lap, such as when watching television, or when the arms are dangling at the side when walking.
• Masked face: The expressionless face of PD is also not generally seen as people age.
• Orthostatic hypotension: This symptom is related to the body’s inability to quickly regulate blood pressure, particularly when sitting up from a lying position or standing from a sitting position. This can cause lightheadedness or a faint feeling. When severe, actual fainting can occur. This is not commonly seen in the general aging population.
• REM behavior sleep disorder: This particular sleep disorder in which a person acts out their dreams is particularly associated with PD and not a sign of general aging.

Symptoms that overlap between PD and aging

Now let’s take a closer look at symptoms that overlap between PD and aging and point out some differences that might help determine the cause.

Difficulty walking

Trouble walking due to Parkinson’s disease

A Parkinson’s disease walk typically involves a stooped posture and decreased arm swing, with flexion at the waist, shoulders, and elbows. A person with PD will place their entire foot on the floor while walking without the normal heel-toe stride or pattern. This gives the walk a shuffling appearance. Someone with PD may also have freezing of gait, which is a gait pattern in which there are sudden, short, and temporary episodes of an inability to move the feet forward despite the intention to walk. This is associated with PD and is not seen in the general aging population. People with PD may also develop postural instability in which the reflexes that allow you to remain upright when thrown off balance are impaired. Postural instability is a cardinal feature of PD that can lead to falls and is not a sign of general aging.

Trouble walking due to aging

However, things may not be as simple as I just stated. Studies have looked at the general aging population and studied whether these individuals show characteristic motor features of PD. It was found that the rate of motor features of PD in a general elderly population who do not meet clinical criteria for an actual PD diagnosis was high and increased with age. This begs the question – are these changes due to the presence of Lewy bodies in the brain as people age, or do they develop because of other age-related changes in the midbrain? This question has not yet been answered.

So, Parkinson’s features can contribute to walking difficulties as people age. But there are many other factors that can contribute as well. Usually, the trouble that people have with walking as they age is multi-factorial, which means that it is due to an accumulation of causes that are common with aging. This is very important because it means that each individual cause must be assessed and treated. A neurologist will carefully observe a person’s gait for features of the various causes of gait impairment. He/she may decide to order tests (blood tests imaging tests, electromyography (EMG) to try to tease out and treat the contributing factors.

Some of the reasons that contribute to difficulty walking with aging are:

• Peripheral neuropathy: this refers to damage to the nerves that send and retrieve information to the body and limbs. The longest of these nerves feed the feet and they are most prone to damage from numerous causes including vitamin deficiencies, diabetes, and certain autoimmune conditions. People with peripheral neuropathy may experience numbness or pain (such as burning sensations of electric shock sensations) in their feet. Peripheral neuropathy can contribute to weakness of the muscles in the feet. In addition, it can inhibit sensory input into the feet so that a person does not properly sense where their feet are in space. Both weakness and lack of sensation can contribute to walking problems.  
• Spinal stenosis and pinched nerves: The vertebrae are individual bones that line up to form the spinal column through which the spinal cord runs. Narrowing of the central spinal canal, most commonly in the lower back or neck, is called spinal stenosis and is a common condition that develops with age. Narrowing of the exit holes through which the spinal nerves travel (resulting in radiculopathy or pinched nerves) is also very common with aging and can be caused by arthritis, bony spurs, herniated discs, or compression fractures. Compression of these nerve structures can cause weakness and sensory changes in the legs and feet and can contribute to pain and walking difficulties.
• Cerebral small vessel disease: this refers to damage to the small blood vessels in the brain that occurs over time, often due to vascular risk factors such as high blood pressure, high cholesterol, and diabetes. These risk factors can lead to atherosclerosis or buildup of plaque in the inner lining of the arteries in the brain which contribute to small strokes or bleeds. Often, these individual strokes may be silent, and the person is unaware of a problem. But as these small strokes accumulate, they can slowly lead to difficulty walking, falls and cognitive impairment.
• Poor eyesight: As eyesight deteriorates with age, it is harder to navigate the environment, which can impact gait and fall risk.
• Vestibular loss: The vestibular system is a set of sensory organs in the inner ear that allows a person to maintain balance, posture, and spatial orientation. Damage to the nerves in this system often occurs with age and can result in vertigo, instability and loss of balance.

Pain  

Pain due to Parkinson’s disease

Pain is an often-overlooked non-motor symptom of PD. There are specific reasons why pain can be a feature of PD including pain due to rigidity or stiffness. Dystonic pain is due to abnormal muscle contractions that can occur in PD. The pain of PD can also be central pain, caused by neurodegeneration in parts of the brain that control pain.

Pain due to aging

Wear and tear of the nerves, bones, joints, and muscles can cause the pain of aging. Some of these problems overlap with the causes of walking difficulties mentioned above, including peripheral neuropathy, spinal stenosis, and radiculopathy, as well as arthritis that can cause pain in joints throughout the body.

Urinary dysfunction

Urinary dysfunction due to Parkinson’s disease

Urinary frequency and urgency in PD are most caused by abnormal innervation of the bladder resulting in overactivity of the bladder muscle called the detrusor muscle. This muscle contracts excessively even though it is not filled with urine. This causes an increased urge to urinate and/or an increased frequency of urination, which can be especially prominent at night.

Urinary dysfunction due to aging

As people age, the bladder loses some of its elasticity, which means that a person may feel the need to urinate more frequently. The muscles of the bladder and pelvic floor also weaken which may make it difficult to empty the bladder completely or cause loss of control of urine. In men, an enlarged prostate can cause urinary urgency and frequency.

Constipation

Constipation due to Parkinson’s disease

Constipation is the most common non-motor symptom of PD and is due to alpha-synuclein accumulation in Lewy body-like structures in the nerves that line the gut. This results in a general slowness of the gut which leads to constipation.

Constipation due to aging

Structural changes of the large intestine as people age can cause constipation. In addition, diabetes and being more sedentary with age can contribute to this difficult problem.

Difficulty sleeping

Difficulty sleeping due to Parkinson’s disease

There are many sleep disorders that are associated with PD including:

• Rapid eye movement (REM) behavior sleep disorder (RBD): a sleep disorder in which the affected person is not paralyzed during dreaming (which is normally what occurs) and can therefore act out his/her dreams
• Insomnia: an inability to fall asleep at the beginning of the night or in the middle of the night upon awakening
• Restless leg syndrome: uncomfortable sensations, usually in the legs, which are temporarily relieved by movement of the legs
• Sleep apnea: a disorder in which breathing stops and starts through the night, leading to periods of low oxygenation in the blood and frequent awakenings
• Sleep fragmentation: frequent brief arousals during sleep which can cause sleep to be less restful

Difficulty sleeping due to aging

Many of the above sleep disorders are also common as people age. Older adults can also experience circadian rhythm sleep disorders, a group of sleep disorders that cause disruption in timing of sleep. Advanced phase sleep disorder, in which a person falls asleep in the early evening and wakes up in the early morning is common as people age. Multiple other issues can contribute to sleeping difficulties with age including medication effect, depression, pain, and urinary frequency.

Cognitive difficulties

Cognitive difficulties due to Parkinson’s disease

Cognitive changes can be an intrinsic part of PD, caused by abnormal accumulation of the protein alpha-synuclein into Lewy bodies in the thinking areas of the brain. The cognitive changes that people with PD may notice are difficulty with executive functioning (the ability to plan, organize, initiate, and regulate goal-directed behavior) and visuo-spatial functioning (the ability to estimate distance and depth perception, use mental imagery, copy drawings, or construct objects or shapes).

Cognitive difficulties due to aging

As people age, they may notice subtle changes in their thinking. Neuropsychiatric testing can help to distinguish whether these are due to expected changes in the brain or due to a disease state. Testing will investigate the various cognitive domains (e.g., memory, language, executive functioning, etc.) and determine whether abilities are the same or different than age matched controls. There are numerous disease states besides PD that can contribute to changes in thinking including Alzheimer’s disease and cerebral vascular disease.

Tips and takeaways

• It can be challenging to determine the cause of certain symptoms because there is a significant amount of overlap between symptoms that a person may experience with regular aging and the symptoms of Parkinson’s disease.
• While the symptoms may be similar between aging and PD, they may have different underlying causes.
• However, there are some symptoms that are distinctly common in Parkinson’s disease, but are not common with aging.
• Talk with your doctor about all your symptoms. He/she can help you figure out why you are having the symptom(s).
• Regardless of cause, you can seek treatment for your symptoms. There may be treatments available that can minimize the symptom(s) and improve your quality of life.
• Download the APDA Symptom Tracker App to help you more easily and accurately track your symptoms, so you can help your doctor understand what you are experiencing.