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.
Other signs of Parkinson disease may include:
- Small,
cramped handwriting
- Stiff
facial expression
- Shuffling
walk
- Muffled
speech
- Depression
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.
Who does it affect?
Parkinson disease affects about 1 in 300 people
in the general population. The occurrence increases
with age to 1 in 100 at the age of 65 and to
about 3 in 100 at the age of 85. There are currently
between 500,000 and a million people in the
United States with Parkinson disease. Most people
are diagnosed with the disease between the ages
of 50 and 60 and about 85 percent of people
with Parkinson are over the age of 65. There
are approximately 60,000 new cases of PD diagnosed
each year and this number is increasing yearly.
Men are almost 1.3 times more likely to be diagnosed
than women.
What causes PD?
The
cause for Parkinson disease has not been established.
A primary risk factor for PD is age.
There also appears to be a genetic predisposition
that when combined with an environmental factor
causes extreme neuron death in the part of the
brain that controls movement. Some of the environmental
toxins include:
When
the cause of Parkinson disease is not associated
with any of these factors, it is termed idiopathic (meaning “unknown cause”) Parkinson disease. This category makes up about 85 percent of
those with Parkinson disease.
How
do you get it?
The
cells in the part of the brain called the substantia
nigra produce a neurotransmitter called
dopamine. Dopamine is necessary for motor neurons
to communicate with each other to initiate and
continue ordinary movements. As people age,
some of the cells die off naturally. In most
people, approximately 35 percent of these dopamine-producing
cells are gone by age 60. By the age of 80 to 90, over three quarters
of these cells have died, leaving a diminished
number of cells to supply other parts of the
brain with dopamine. In people with Parkinson
disease, the cells die much more prematurely
than usual, creating dopamine deficiency at
an earlier age.
This profound shortage of dopamine leaves brain
cells unable to pass along the message of what
to do in areas of the brain that normally regulate
such vital skills as standing, sitting, and
walking.
When
a person develops symptoms of PD, it means that
there has already been severe loss of cells
in the substantia nigra, probably around 75
to 80 percent. Depending on which nerves are
lost, symptoms may start in different parts
of the body on each side.
How
does it progress?
Initially
the symptoms are mild, usually on one side of
the body, and may not require medical treatment.
Resting 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 monotone. A disturbance of balance
may lead to falls. Handwriting becomes small
(“micrographia”) and illegible.
Automatic movements, such as arm swing when
walking, are reduced.
Symptoms
may originally be restricted to one limb, but
will typically spread over time to the other
limb on the same side. They eventually
progress to the other side of the body.
Generally this progression is gradual, but the
rate of progression varies in different patients.
It
is not possible to predict with any confidence
the likely course of the disease in an individual
patient. The rate of progression and resulting
level of disability vary from patient to patient. Some
indication of the likely outcome in individual
patients is provided by its progression since
first being diagnosed, but this is only suggestive
of te future course.
Is there a cure?
To
date there is no cure for Parkinson disease.
In addition, because there is no definitive
cause for the disease, it is not preventable.
The management of Parkinson disease is based
on relieving the symptoms as much as possible.
The management of the disease can include: harmaceutical
therapy, vitamin supplementation, good nutrition,
exercise, and in some cases,surgery.
There are a number of effective medicines that ease the symptoms
of Parkinson disease. Most symptoms are
caused by lack of dopamine.
The medicines most commonly used will attempt
to either replace or mimic dopamine, which improves
the tremor, rigidity, and slowness associated
with Parkinson disease. Several new medicines
are being studied that may slow the progression.
Many promise to improve the lives of people
with Parkinson disease.
A
relatively new surgical procedure that was approved
by the FDA in 2002 can reduce symptoms and reliance
on medications. This procedure called “Deep Brain Stimulation”
inserts two small electrodes into a portion
of the brain that regulates much of the movement
affected by PD.
The electrodes are connected to two pacemaker-type
devices implanted under the skin in the chest
that send small electrical impulses that may
help relieve tremors, rigidity and slowness.
DBS surgery can ease the symptoms of Parkinson
disease, but it is not a cure.
What’s in the future?
There
is much research being done that scientists
hope will lead to identifying the cause and,
eventually, discovering a cure. Cell transplantation,
gene therapy, and the injection of nerve growth
factors
may offer a potential cure in the future.
