What is Parkinson's disease?

Dr. Nader Pouratian, MD

Parkinson’s disease is a movement disorder characterized primarily by tremor at rest, stiffness and slowness of movements. The disease and its symptoms are due to degeneration of a very specific part of the brain called the substantia nigra, resulting in loss of dopamine in the brain. Treatment, therefore, focuses on giving patients drugs that increase dopamine levels of the brain or that act like dopamine on the brain. Surgery focuses on correcting abnormal activity in the delicate circuits in the brain that are affected by Parkinson’s disease. While Parkinson’s disease is considered a movement disorder, there are important and often disabling non-motor symptoms as well, including depression, constipation, loss of smell, vivid dreams, balance problems and other problems. Although many people are afflicted by Parkinson’s disease, a precise cause is not known. It is believed, however, that people with pesticide exposures early in life are at increased risk.

Parkinson's disease is a degenerative disorder of the central nervous system. This disease belongs to a group of conditions called motor system disorders and is the result of the loss of dopamine-producing brain cells. The disease is both chronic, meaning it persists over a long period, and progressive, meaning its symptoms grow worse over time. It is not contagious. Although some cases of Parkinson's disease appear to be hereditary and a few can be traced to specific genetic mutations, most cases are sporadic, that is, the disease does not seem to run in families. Many researchers now believe that Parkinson's disease results from a combination of genetic susceptibility and exposure to one or more environmental factors that trigger the disease.

This answer is based on source information from the National Institute of Neurological Disorders and Stroke.

Parkinson's disease is a movement disorder resulting from a deficiency of dopamine, a neurotransmitter involved in coordinating muscle activity as well as memory function. Its hallmarks include tremors, rigid limbs, and difficulty starting or stopping movement. Mild cognitive problems are common early in the disease, and dementia occurs in 30% to 80% of Parkinson's patients in the late stages.

In 1817, Dr. James Parkinson, a British physician was first to describe a disease with these characteristics:

  • Shaking-while the limb is at rest
  • Slowness of movement, also known as bradykinesia
  • Increased resistance to passive movement, or stiffness, such as a rigidity of the trunk or limbs
  • Postural instability or poor balance

For someone to be diagnosed with Parkinson's, he or she must have at least two of those symptoms.

Parkinson’s disease is a condition that affects the body's ability to move in certain ways. It happens the brain can't make enough of a brain chemical called dopamine. It can cause trembling, stiffness and loss of balance and coordination. As the disease gets worse, it can make it hard to walk, talk and swallow.

Parkinson's disease affects the part of the brain called the basal ganglia. The basal ganglia controls automatic movements, such as picking up a glass or moving the legs to walk.

Parkinson's disease often affects people after age 60, but it can start earlier. It affects both men and women but is more common in men.

Because there is no lab test for it, Parkinson's disease can be hard to diagnose. Doctors diagnose it based on symptoms and a physical exam. Although there is no cure for Parkinson's condition, treatments are available to slow its progress.

Parkinson's disease is a progressive neurological disorder caused by the loss of specific groups of nerve cells in the brain. Parkinson's disease affects people of all ages, but becomes increasingly common as people get older. More than a million people in the United States have the disease, including 1 percent of people over the age of 60. Many symptoms of Parkinson's disease – shaking, slowness, stiffness, anxiety, depression, and difficulty sleeping--remain mild and treatable for many years. No two people with Parkinson's disease have exactly the same symptoms or responses to treatment.

Chemicals in the brain called neurotransmitters produce signals that regulate muscle movement throughout the body. In people with Parkinson's disease, specific brain cells stop working properly, including those that produce the neurotransmitter dopamine. As levels of dopamine fall, patients have increasing difficulty controlling their movements. Medications that replace dopamine and correct other chemical imbalances help to control the symptoms of Parkinson's disease. A number of different genes for Parkinson's disease have been identified, but environmental factors are also believed to influence risk.

In its early stages, Parkinson's disease may be difficult to diagnose: doctors might not consider this diagnosis in younger patients, and in older patients they may incorrectly attribute the symptoms to the aging process.

Parkinson's disease (PD) is a Movement Disorder, which is chronic and slowly progressive, where nerve cells in the brain (substantia Nigra pars compacta) start to die well before physical symptoms occurs. These cells produce Dopamine, which helps with motor (physical) movement such as walking, speed of movement and fine motor coordination. The symptoms that occur before physical symptoms are called pre-motor or non-motor symptoms. These are red flags signally a potential increase risk of Parkinson's Disease. 

Non-Motor Symptoms with the highest risk-

  • REM Behavior Sleep Disorder (Acting our dreams in Sleep by talking or moving arms and legs) with an average of 12 years before physical symptoms.
  • Decreased or No Sense of Smell (Hyposmia or Anosmia) as much as 5 years or more before physical symptoms.
  • Constipation with an average of (less than one bowel movement/day) 3 years or more before physical symptoms. 

Depression, Anxiety, Cognitive Difficulty, (thinking or Processing), Apathy and Visual Disturbances are also non-motor symptoms. 

Motor Symptoms occur when 50%-70% if the nerve cells in the Substantia Nigra have died. Two out of three symptoms that are used in diagnosis are:

  • Rigidity
  • Slowness of movement (bradykinesia) 
  • Tremor starting in One Arm and/or Leg

Usually decrease volume of one’s voice, small handwriting, decreased arm swing and shuffling or taking shorter steps are early motor signs as well. 

Parkinson's disease is a clinical diagnosis made by physician, there is no blood test or imaging to diagnosis idiopathic Parkinson's Disease.

Parkinson's disease is frequently misdiagnosed as Essential Tremor or mistaken for Multiple System Atrophy or other atypical Parkinson Syndromes that don't respond to medications by General Neurologists, Neurosurgeons or other Physicians. A Movement Disorder Specialist is a Neurologist who does an extra 1-2 years of training (A Fellowship). Any Neurologist can call themselves a Movement Disorder Specialist, so find out if they have done a fellowship. 

Exercise, medications and deep brain stimulation surgery can help the symptoms of Parkinson's disease, allowing patients to be more functional. Lack of Sleep worsens symptoms. There is no cure for Parkinson's disease yet, however, research is getting closer in understanding Parkinson's Disease and for biomarkers that can help in early diagnosis and following progression.

Parkinson's disease is a degenerative nerve disorder. It usually starts slowly and becomes worse over time. Parkinson's may begin with a simple muscle tremor, often in one hand. It may also cause slowness of voluntary movements, muscle stiffness, imbalance, changes in speech, and dementia. Parkinson's is known as a motor-system disorder because it affects the parts of the brain that control movement.

Parkinson’s disease is a condition where the brain cells that make dopamine gradually stop working. Normally, brain cells make and use chemical messengers. Dopamine is an important one that sends instructions to the body about movement. If not enough dopamine is made, the instructions can’t get delivered. This causes symptoms like shaking, stiffness and slow movements, as well as problems with walking and talking. People with Parkinson’s disease might feel tired and anxious, and they may not want to talk about their condition. Medicines improve the symptoms. Other therapies can help too.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.