symptoms of parkinsons disease : PARKINSON PRIMER

Overview of Parkinson Disease

Parkinson disease (PD) was first described in 1817 by Dr. James Parkinson, a British physician, for whom the disease was named. It is a disease that is characterized by four major features:

Rest tremor of a limb (shaking with the limb at rest)
Slowness of movement (bradykinesia)
Rigidity (stiffness, increased resistance to passive movement) of the limbs or trunk
Poor balance (postural instability)
When at least two of these symptoms are present, and especially if they are more evident on one side than the other, a diagnosis of PD is made, unless there are atypical features that suggest an alternative diagnosis. Patients may first realize something is wrong when they develop a tremor in a limb; movements are slowed and activities take longer to perform; or they experience stiffness and have balance problems. Initially, symptoms are a variable combination of tremor, bradykinesia, rigidity and postural instability. Symptoms typically begin on one side of the body and spread over time to the other side.

Changes occur in facial expression, so that there is a certain facial fixity (blank expression showing little emotion) or a staring appearance (due to reduced frequency of eye blinking). Complaints of a frozen shoulder or foot drag on the affected side are not uncommon. As symptoms come on gradually, older patients may attribute these changes to aging. The tremor is thought to be “shakiness,” bradykinesia is regarded as normal “slowing down,” and stiffness is attributed to arthritis. The stooped posture, common to PD, may be attributed to age or osteoporosis. Both younger and older patients may experience initial symptoms for a year or more before seeking medical evaluation.

Parkinson disease affects 1 in 100 people over the age of 60, with the average age of onset being 60 years. It can also affect younger people. Young-onset Parkinson disease (onset at age 40 or younger) is estimated to occur in 5 – 10% of patients with PD.

Disease Progression

After Alzheimer’s disease, Parkinson disease is the most common neurodegenerative disease.

It is a chronic, progressive disease that results when nerve cells in a part of the midbrain, called the substantia nigra, die or are impaired. These nerve cells produce dopamine, an important chemical messenger that transmits signals from the substantia nigra to another part of the brain called the corpus striatum. These signals allow for coordinated movement. When the dopamine-secreting cells in the substantia nigra die, the other movement control centers in the brain become unregulated. These disturbances in the control centers of the brain cause the symptoms of PD. When 80% of the dopamine-producing cells in the substantia nigra are depleted, symptoms of PD develop.

Initially the symptoms are mild, usually on one side of the body, and may not require medical treatment. Rest tremor is a major characteristic of PD, and the most common presenting symptom, but some patients never develop it. Tremor may be the least disabling symptom, but is often the most embarrassing to the patient. Patients may keep their affected hand in their pocket, behind their back, or hold something to control the tremor, which may be more psychologically distressing than any physical limitation that it imposes.

Over time, initial symptoms become worse. A mild tremor becomes more bothersome and more noticeable. Difficulties may develop with cutting food or handling utensils with the affected limb. Bradykinesia (slowness in movement) becomes a significant problem and the most disabling symptom. Slowness may interfere with daily routines; getting dressed, shaving or showering may take much of the day. Mobility is impaired and difficulty develops in getting into or out of a chair or a car, or turning over in bed. Walking is slower and there is a stooped posture, with the head and shoulders hanging forward. The voice becomes soft and monotonous. A disturbance of balance may lead to falls. Handwriting becomes small (“micrographia”) and illegible. Automatic movements, such as arm swing when walking, are reduced.

by Mariann Di Minno, RN, MA, and Michael J. Aminoff, MD, DSc, of the Parkinson’s Disease Clinic and Research Center at the University of California, San Francisco.