About Parkinson's Disease

What is Parkinson's Disease?

Parkinson’s Disease (PD) is a chronic and progressive movement disorder that affects nerve cells within the brain. These neurons are found within the area of the brain called the substantia nigra and are responsible for producing dopamine, a chemical that sends messages to the part of the brain responsible for controlling movement and coordination. As PD progresses, the amount of dopamine produced in the brain decreases, making normal movement control more difficult. Messages from the brain telling the body how and when to move are delivered abnormally, making initiating and controlling movement in a normal way difficult. This process leads to the characteristic motor symptoms of PD.

Primary motor signs of Parkinson’s disease include tremor, slowness (bradykinesia), rigidity, and postural instability. Most people with Parkinson’s also experience non-motor symptoms, which include loss of sense of smell, constipation, mood and sleep disorders, and neurogenic orthostatic hypotension (low blood pressure when standing up). Some of these non-motor symptoms may precede motor symptoms.

How is Parkinson's Disease diagnosed?

Although there are no standard diagnostic tests for Parkinson’s, some imaging technology can assist in excluding other diseases that imitate Parkinson’s disease, such as stroke or hydrocephalus. The diagnosis of Parkinson’s is typically made initially by a person’s internist or family physician through careful neurological history and examination. Many people seek additional opinions from a neurologist or movement disorder specialist, who has specific training in assessment and treatment of PD.

What are the stages of Parkinson’s Disease?

The stages of Parkinson’s correspond with the severity of movement symptoms and how much the disease affects a person’s daily activities.

Early or mild Parkinson’s is often associated with movement symptoms, particularly tremor and typically occurs on one side of the body. People may notice changes in their posture, walking ability, and/or facial expressions. Regular exercise helps to improve and maintain mobility, flexibility, range of motion (ROM), and balance, as well as assists in reducing depression and constipation.

With moderate Parkinson’s Disease, movement symptoms occur on both sides of the body and people may notices that their body moves more slowly. Trouble with balance and coordination may develop, as well as “freezing episodes”. Medications may “wear off” between scheduled doses and may cause side effects such as dyskinesia (involuntary movements). Regular exercise, and participation in physical therapy, continues to be important for balance, mobility, and strategies for maintaining independence.

With advanced Parkinson’s, a person may experience greater difficulty with walking, may require an assistive device or wheelchair and greater assistance with daily activities. Cognitive impairments may be prominent, including hallucinations and delusions. Balancing the benefits of medications with their side effects can become more challenging during this stage of Parkinson's.

It is important to remember that each person’s experience with Parkinson’s is different, including the progression of their symptoms within each stage. Although your physician cannot accurately predict the course of Parkinson’s for any individual, they, in addition with your care team, can focus on reducing a person’s symptoms, preventing complications, and improving quality of life.

Parkinson's Disease: Motor Symptoms

A Parkinson’s diagnosis requires a careful medical history and physical examination to detect the cardinal signs of the disease. Below is a list of common motor symptoms in which you may experience and can discuss with your physician and physical therapist.

Resting Tremor
The typical tremor experienced with Parkinson’s occurs mostly at rest and lessens when the body part is actively in use. For example, your hand may shake when you’re sitting, but when you reach out to shake someone’s hand the tremor is less noticeable or goes away entirely. Tremor usually affects only one side of the body, especially in the early stages of PD, but may progress to both sides as the disease progresses. Fatigue, stress, or intense emotions can temporarily make tremors worse.

Bradykinesia
Bradykinesia is the slowness of movement, often one of the cardinal symptoms of Parkinson’s disease. This slowness can occur in different ways such as reduction of automatic movements such as swinging your arms when walking, difficulty initiating movement such as getting up out of a chair, general slowness in actions, and the appearance of abnormal stillness or a decrease in facial expression. This translates into difficulty performing activities of daily living as well as a shorter step length and shuffling walking pattern.

Rigidity
Rigidity causes stiffness of the limbs, neck, and trunk. In the case of Parkinson’s, some muscles remain stiff and do not relax, contributing to decreased range of motion. This may be observed with less arm swing when walking due to tightness of the neck and shoulder.

Postural Instability
Postural instability is the tendency to be unstable when standing upright. A person with postural instability has lost some of the reflexes needed to maintain an upright posture and may fall backward more easily. This can also contribute to a backward sway when rising from a chair, standing, or turning.

Secondary Motor Symptoms 

• Freezing of gait is a sign of PD where a person will hesitate before stepping forward as if they feel their feet are glued to the floor.
• Microphagia is the name for the shrinkage in handwriting, which occurs as a result of bradykinesia.
• Drooling and excessive saliva result from reduced swallowing movements.
• Mask-like expression, meaning a person's face may appear less expressive than usual, can occur because of decreased unconscious facial movements.
• Flexed posture may result from a combination of rigidity and bradykinesia. 
• Festinating gait, or an uncontrollable acceleration of gait, is one of the types of movements that are too quick instead of too slow. This can place a person at increased risk for falls. 

Parkinson's Disease: Non-motor Symptoms

Most people with Parkinson’s experience non-motor symptoms, which are those that do not involve movement, coordination, physical tasks, or mobility. These “invisible” symptoms may not be as noticeable by friends and family, but can be just as troublesome as motor impairments of PD.

Early non-motor symptoms may precede motor symptoms and a Parkinson’s diagnosis by years. They can include:

• Loss of sense of smell
• Constipation
• Urinary urgency and frequency
• REM/sleep behavior disorder
• Mood disorders
• Neurogenic orthostatic hypotension (low blood pressure when standing up)
• Cognitive changes
• Hallucinations

If a person has one or more of these symptoms, it does not necessarily mean that individual will develop PD, but may help better understand the disease process. Reach out to your neurologist, movement disorder specialist, and care team if you experiencing any of these non-motor symptoms.