What is PD?

There is no cure for PD, but research is ongoing and medications or surgery can often provide substantial improvement with motor symptoms.

The four primary symptoms of PD are:

1. Tremor—Tremor (shaking) often begins in a hand, although sometimes a foot or the jaw is affected first. The tremor associated with PD has a characteristic rhythmic back-and-forth motion that may involve the thumb and forefinger and appear as a “pill rolling.” It is most obvious when the hand is at rest or when a person is under stress. This tremor usually disappears during sleep or improves with a purposeful, intended movement.
2. Rigidity—Rigidity (muscle stiffness), or a resistance to movement, affects most people with PD. The muscles remain constantly tense and contracted so that the person aches or feels stiff. The rigidity becomes obvious when another person tries to move the individual’s arm, which will move only in short, jerky movements known as “cogwheel” rigidity.
3. Bradykinesia—This is a slowing down of spontaneous and automatic movement that can be particularly frustrating because it may make simple tasks difficult. Activities once performed quickly and easily—such as washing or dressing—may take much longer. There is often a decrease in facial expressions (also known as “masked face”).
4. Postural instability—Impaired balance and changes in posture can increase the risk of falls.

PD does not affect everyone the same way. The rate of progression and the particular symptoms differ among individuals. PD symptoms typically begin on one side of the body. However, the disease eventually affects both sides, although symptoms are often less severe on one side than on the other.

People with PD often develop a so-called parkinsonian gait that includes a tendency to lean forward, taking small quick steps as if hurrying (called festination), and reduced swinging in one or both arms. They may have trouble initiating movement (start hesitation), and they may stop suddenly as they walk (freezing).

Other problems may accompany PD, such as:

• Depression—Some people lose their motivation and become dependent on family members.
• Emotional changes—Some people with PD become fearful and insecure, while others may become irritable or uncharacteristically pessimistic.
• Difficulty with swallowing and chewing—Problems with swallowing and chewing may occur in later stages of the disease. Food and saliva may collect in the mouth and back of the throat, which can result in choking or drooling. Getting adequate nutrition may be difficult.
• Speech changes—About half of all individuals with PD have speech difficulties that may be characterized as speaking too softly or in a monotone. Some may hesitate before speaking, slur, or speak too fast.
• Urinary problems or constipation—Bladder and bowel problems can occur due to the improper functioning of the autonomic nervous system, which is responsible for regulating smooth muscle activity.
• Skin problems—The skin on the face may become oily, particularly on the forehead and at the sides of the nose. The scalp may become oily too, resulting in dandruff. In other cases, the skin can become very dry.
• Sleep problems—Common sleep problems in PD include difficulty staying asleep at night, restless sleep, nightmares and emotional dreams, and drowsiness or sudden sleep onset during the day. Another common problem is “REM behavior disorder,” in which people act out their dreams, potentially resulting in injury to themselves or their bed partners. The medications used to treat PD may contribute to some sleep issues. Many of these problems respond to specific therapies.
• Dementia or other cognitive problems—Some people with PD develop memory problems and slow thinking. Cognitive problems become more severe in the late stages of PD, and some people are diagnosed with Parkinson’s disease dementia (PDD). Memory, social judgment, language, reasoning, or other mental skills may be affected.
• Orthostatic hypotension—Orthostatic hypotension is a sudden drop in blood pressure when a person stands up from a lying down or seated position. This may cause dizziness, lightheadedness, and, in extreme cases, loss of balance or fainting. Studies have suggested that, in PD, this problem results from a loss of nerve endings in the sympathetic nervous system, which controls heart rate, blood pressure, and other automatic functions in the body. The medications used to treat PD may also contribute.
• Muscle cramps and dystonia—The rigidity and lack of normal movement associated with PD often causes muscle cramps, especially in the legs and toes. PD can also be associated with dystonia—sustained muscle contractions that cause forced or twisted positions. Dystonia in PD is often caused by fluctuations in the body’s level of dopamine (a chemical in the brain that helps nerve cells communicate and is involved with movement).
• Pain—Muscles and joints may ache because of the rigidity and abnormal postures often associated with the disease.
• Fatigue and loss of energy—Many people with PD often have fatigue, especially late in the day. Fatigue may be associated with depression or sleep disorders, but it may also result from muscle stress or from overdoing activity when the person feels well. Fatigue may also result from akinesia, which is trouble initiating or carrying out movement.
• Sexual dysfunction—Because of its effects on nerve signals from the brain, PD may cause sexual dysfunction. PD-related depression or use of certain medications may also cause decreased sex drive and other problems.
• Hallucinations, delusions, and other psychotic symptoms can be caused by the drugs prescribed for PD.

Diseases and conditions that resemble PD

PD is the most common form of parkinsonism, which describes disorders of other causes that produce features and symptoms that closely resemble Parkinson’s disease. Many disorders can cause symptoms similar to those of PD, including:

• Multiple system atrophy (MSA) refers to a set of slowly progressive disorders that affect the central and autonomic nervous systems. The protein alpha-synuclein forms harmful filament-like aggregates in the supporting cells in the brain called oligodendroglia. MSA may have symptoms that resemble PD. It may also take a form that primarily produces poor coordination and slurred speech, or it may involve a combination of these symptoms. MSA with parkinsonian symptoms is sometimes referred to as MSA-P (or striatonigral degeneration).
• Lewy body dementia is associated with the same abnormal protein deposits (Lewy bodies) found in Parkinson’s disease but appears in areas throughout the brain. Symptoms may range from primary parkinsonian symptoms such as bradykinesia, rigidity, tremor, and shuffling walk, to symptoms similar to those of Alzheimer’s disease (memory loss, poor judgment, and confusion). These symptoms may fluctuate (vary) dramatically. Other symptoms may include visual hallucinations, psychiatric disturbances such as delusions and depression, and problems with cognition.
• Progressive supranuclear palsy (PSP) is a rare, progressive brain disorder caused by a gradual deterioration of cells in the brain stem. Symptoms may include problems with control of gait and balance (people often tend to fall early in the course of PSP), an inability to move the eyes, and alterations of mood and behavior, including depression and apathy as well as mild dementia. PSP is characterized by clumps of a protein called tau.
• Corticobasal degeneration (CBD) results from atrophy of multiple areas of the brain, including the cerebral cortex and the basal ganglia. Initial symptoms may first appear on one side of the body, but eventually affect both sides. Symptoms include rigidity, impaired balance, and problems with coordination. Other symptoms may include dystonia that affects one side of the body, cognitive and visual-spatial impairments, apraxia (loss of the ability to make familiar, purposeful movements), hesitant and halting speech, myoclonus (muscular jerks), and dysphagia (difficulty swallowing). CBD also is characterized by deposits of the tau protein.

Several diseases, including MSA, CBD, and PSP, are sometimes referred to as “Parkinson’s-plus” diseases because they have the symptoms of PD plus additional features.

In very rare cases, parkinsonian symptoms may appear in people before the age of 20. This condition is called juvenile parkinsonism. It often begins with dystonia and bradykinesia, and the symptoms often improve with levodopa medication.