The hallmark symptoms of Parkinson disease are tremors and slow, rigid movements. Small changes in a person’s movements and behavior can signal the onset of Parkinson’s disease before diagnosis.
Parkinson disease is a nervous system disorder that affects around 1 percent of people aged 65 years and older. Symptoms usually develop slowly over several years. They may be subtle at first, so early signs are easy to miss.
If someone notices symptoms of Parkinson disease, they should consider contacting their doctor for more information. Early treatment can improve the condition’s long-term outcome.
In this article, we cover some of the early signs of Parkinson disease, alongside its diagnosis and major possible risk factors.
Early symptoms of Parkinson disease include:
Many healthcare professionals consider tremors to be a key characteristic sign of Parkinson’s disease. Tremors involve a persistent twitching or shaking of the hands, legs, or chin.
Tremors associated with Parkinson disease are called “rest tremors.” This means that the tremors stop when a person uses the affected body part.
Tremors are very subtle when they first appear. At this stage, the person experiencing the tremors is usually the only one who notices them. Tremors will gradually worsen as the disease progresses.
Tremors typically appear on one side of the body and then spread to other parts of the body later on.
- Difficulty in walking
Subtle changes in a person’s walking pattern could be an early sign of Parkinson disease.
Someone who has Parkinson disease might walk slowly or drag their feet as they walk. Many refer to this as a “shuffling gait.”
The person might walk at an irregular pace, suddenly walking faster or slower or changing the length of their stride.
- Cramped or small handwriting
Micrographia is a disorder that involves abnormally small or cramped handwriting.
Doctors associate micrographia with medical conditions that affect the nervous system, or neurodegenerative disorders, such as Parkinson’s disease.
- Loss of smell
Hyposmia occurs when someone loses their ability to smell. This is also called olfactory dysfunction. A loss of smell is a relatively common symptom, affecting 70–90 percent of people with Parkinson’s disease.
Loss of smell is one of the most noticeable symptoms of Parkinson disease that is not related to movement. It can appear several years before the disease affects a person’s movement.
People who have hyposmia as a symptom of Parkinson disease might experience:
- a dulled sense of smell
- difficulty detecting odors
- difficulty identifying odors
- difficulty telling the difference between odors
Doctors use smell identification tests to diagnose hyposmia, but the accuracy of these tests varies widely.
Having hyposmia does not always mean that someone has Parkinson’s disease. A person’s sense of smell can change for many reasons, such as age, smoking, or exposure to harsh chemicals. Hyposmia is also a symptom of other medical conditions, including Alzheimer’s disease and Huntington’s disease.
- Sleep problems
Parkinson disease can severely affect a person’s ability to sleep. People who have Parkinson’s disease may experience a wide range of sleep-related symptoms, including:
- excessive daytime fatigue
- sleep apnea
- uncontrolled or sporadic movements while asleep
- Poor balance
Parkinson disease specifically targets nerve cells called basal ganglia, which reside deep within the brain. Basal ganglia nerves control balance and flexibility, so any damage to these nerves can impair a person’s balance.
Doctors use a test called the pull test to assess a person’s balance. The pull test involves a healthcare professional gently pulling a person’s shoulders backward until they lose their balance and recording how long it takes them to regain it.
Healthy individuals recover after one or two steps, while people with Parkinson’s disease may take a higher number of smaller steps to fully balance themselves.
Bradykinesia is a term that means slowness or absence of movement. Bradykinesia causes a variety of symptoms, such as stiffness of the limbs and slow movements. A person who has bradykinesia might walk slower or have difficult starting a movement.
Some people who have this symptom might misinterpret it as muscle weakness. However, this symptom does not affect muscle strength.
- Facial masking
Facial expressions involve many subtle, complex muscle movements. People with Parkinson’s disease often have a reduced ability to make facial expressions. This is called facial masking.
Facial masking is related to bradykinesia. The facial muscles move more slowly or rigidly than usual. People who have facial masking may appear blank or emotionless, though their ability to feel emotions is not impaired. Facial masking can also cause someone to blink their eyes slower.
A person with facial masking might have difficulty communicating with others because changes in their facial expressions are less noticeable than usual.
- Vocal changes
Changes in the volume and quality of a person’s voice is another early sign of Parkinson’s disease. Vocal changes may involve speaking in a softer tone, or starting to speak at a usual volume and then the voice becomes softer or fades away.
In other cases, a person might lose the usual variation in the volume and tone of their voice, so that the voice appears monotonous.
Other Early signs of this health condition may include:
- stooping or hunched posture
- psychological symptoms
- weight loss
Having these symptoms does not always mean that a person has Parkinson’s disease. People over the age of 60 should consider speaking with their healthcare provider if they experience any of the symptoms listed above.
Early diagnosis leads to earlier treatment, which can improve a person’s overall quality of life.
Is Parkinson’s disease hereditary?
Parkinson’s disease can be hereditary, but most cases are not. Only around 15% of people with Parkinson’s disease have a family history of the condition.
As well as genetic changes, environmental factors — such as exposure to toxins, the use of certain drugs, and traumatic brain injury — may also increase the risk. Most cases develop without a clear reason.
If a sibling or family member has Parkinson’s disease, an individual may have a higher chance of developing it themselves. However, most cases are not hereditary.
In addition, not everyone with the relevant genetic features or family history will develop Parkinson’s disease. A person might have features that increase the risk but never develop symptoms.
Most likely, environmental factors also need to be present.
Genetics and Parkinson’s disease
The symptoms of Parkinson’s disease appear to occur when the brain is no longer able to produce enough dopamine. Low dopamine levels in the brain can affect movement. It is not yet clear what role genetic factors may play in this process.
However, experts have identified specific genes in which changes appear to increase the risk of developing Parkinson’s disease. The symptoms a person experiences may depend on their specific genetic changes.
Genetic changes can affect how mitochondria work. Mitochondria are the parts of a cell that produce energy. As they do this, they release by-products commonly known as free radicals. Free radicals can cause cell damage.
Usually, cells can counter free radicals, but genetic changes can stop this from happening, and the free radicals can cause damage to dopamine cells.
Genetic changes can also lead to accumulations of a protein called alpha-synuclein in and around neurons throughout the brain. These accumulations are known as Lewy bodies, and the damage they cause can result in Lewy body dementia, which has links to Parkinson’s disease.
Dopamine-producing nerve cells appear to be particularly susceptible to Lewy bodies, and some people develop both Parkinson’s disease and Lewy body dementia.
Symptoms of Lewy body dementia include REM sleep behaviour disorder, changes in thinking, hallucinations, and Parkinsonism. Parkinsonism refers to any condition that involves tremors, slowness of movement, or other symptoms similar to those that occur with Parkinson’s disease.
Specific gene changes have specific outcomes. For example, SNCA affects the processing of alpha-synuclein, and PRKN impacts how mitochondria work.
Genes associated with Parkinson’s disease
The genetic changes involved in Parkinson’s disease can be:
- autosomal dominant
- autosomal recessive
Studies have found different genes linked to Parkinson’s disease in different patterns of inheritance. They are still investigating whether or not these genes can follow both patterns and if they are more likely to be present in people who develop symptoms before the age of 30 years.
Autosomal dominant genetic features
People have two copies of each gene. In autosomal dominant inheritance, a child can inherit either a healthy gene or one that is not working correctly. They will have a 50% chance of inheriting a faulty gene.
Autosomal dominant genes that scientists have associated with Parkinson’s disease include:
- SNCA, or PARK1
- UCHL1, or PARK5
- LRRK2, or PARK8
Autosomal recessive genetic features
In autosomal recessive inheritance, two parents have a faulty gene but not the condition linked to it. This is because they still both have one healthy gene.
However, their offspring can inherit two copies of the faulty gene. The offspring will have a 25% chance of inheriting two faulty genes.
Inheriting two faulty copies of the following genes, one from each parent, increases the risk of Parkinson’s disease:
- PINK1, or PARK6
It is important to note that inheriting any of the genes that scientists have identified as being related to Parkinson’s disease does not necessarily mean that a person will develop the condition.
As well as family history, the following factors may increase the risk of Parkinson’s disease:
- being aged 60 years or above
- being male, as Parkinson’s disease affects around 50%Trusted Source more males than females
- having past exposure to certain toxins, such as pesticides
- having a history of head trauma or concussion
- also, having certain medical conditions, such as an infection
Diagnosing Parkinson disease
There is no specific test for Parkinson’s disease. This can make it hard to diagnose, especially in the early stages. To diagnose it, a doctor will consider the person’s symptoms and may suggest some tests.
The symptoms of Parkinson’s disease mainly result from changes in dopamine activity in the brain. Tremors are a hallmark symptom, but other early symptoms include a loss of the sense of smell. The symptoms can overlap with those of other conditions, such as Lewy body dementia and some types of stroke. Lewy body dementia can also occur with Parkinson’s disease.
Some antipsychotic medications can cause Parkinsonism. The symptoms of this are similar to those of Parkinson’s disease, but the diagnosis is different.
Getting an accurate diagnosis can help improve the outlook, as receiving early treatment can improve a person’s quality of life. Some drugs may help slow or prevent some changes.
How do doctors diagnose Parkinson disease?
Since there is no specific test for diagnosing the disease condition, a doctor may have to diagnose it only by considering the symptoms present.
If a person seeks medical advice for the following symptoms, the doctor may carry out tests to see if they have Parkinson’s disease:
- shaking or tremors during rest
- slow movements
- muscle stiffness and rigidity
- problems with balance and coordination, possibly leading to falls
- a loss of the sense of smell
- sleep problems, especially REM sleep behaviour disorder or restless legs syndrome
The doctor will usually start by asking the person about their symptoms, how they feel, and how and when the symptoms started.
They will also carry out a physical examination, look at the individual’s medical history, and recommend some tests to rule out other conditions.
The doctor will ask about:
- any existing conditions the person has
- any drugs they are currently taking
- whether or not they have had exposure to environmental toxins
- whether or not any close family members have or have had Parkinson’s
- whether or not they have any known genetic factors that might increase their risk
The early symptoms can resemble those of other conditions.
If a doctor believes that the person may have Parkinson’s disease, they may refer them to a neurologist or movement disorder specialist.
Assessing the symptoms
The specialist will evaluate the person’s motor function (movement). They will consider:
- walking and gait
- coordination and balance
- some simple hand tasks
- the agility of the legs and arms
- muscle tone
The specialist may also check the person’s sense of smell and ask about pain.
They may prescribe a medication such as levodopa, which increases dopamine levels in the brain. If the person’s symptoms improve with this medication, it may indicate that Parkinson’s disease is present.
The following tests may help diagnose Parkinson’s disease:
Dopamine transporter scans
When a person has a dopamine transporter scan, a doctor will give them a small amount of a radioactive drug. Then, the doctor will scan the brain to check for activity in dopamine-producing cells.
The scan cannot diagnose Parkinson’s disease, but it may help support the doctor’s diagnosis.
It is important to note that the person may have a negative result and still have Parkinson’s disease. A positive result could also indicate another, similar condition, such as multiple system atrophy.
This is not a common test. Medicare and Medicaid will usually cover the cost of a scan, but the person should check with their insurance provider first.
Tests to rule out other conditions
Blood tests can help rule out other possible causes of the symptoms, such as abnormal thyroid hormone levels or liver damage.
An MRI or CT scan can check for signs of a stroke or brain tumor, which may cause similar symptoms.
Hydrocephalus (increased fluid in the brain) due to atrophy can occur with some types of dementia and would be visible with one of these imaging tests. If the person has neurologic symptoms but a normal scan result, Parkinson’s disease may be present.
The doctor may suggest a lumbar puncture to rule out inflammation or a brain infection.
Future testing options
Some experts are investigating blood tests to help distinguish Parkinson’s disease from other Parkinson’s-related conditions. However, these tests are not yet available.
People with Parkinson’s disease often have patchy areas on the skin that are dry and flaky. Some researchers have noted that Parkinson’s disease can also cause unusual sweating, bullous pemphigoid (blistering ulcers on the skin), and other skin changes. Because of this, they have proposed a skin biopsy as a future diagnostic tool.
Receiving a diagnosis of Parkinson’s disease can be a life changing event for an individual and their loved ones. Having support from doctors, friends, and family will be important.
It can help to find out as much information as possible about:
- what to expect
- what the treatment options are
- what kind of support is available
- what kind of treatment one’s insurance will cover
It may also be helpful to join a local or online community group for people with Parkinson’s disease and their loved ones. A doctor will be able to advise on this.
National disease-specific organizations, such as the Parkinson’s Foundation, can also offer advice and information.