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from Video of Hillary Clinton suffering apparent stroke on camera. Our
link to the video is below; click on the photo in the lower right.
https://www.youtube.com/watch?v=YMHOcmDVBP0
What is progressive supranuclear palsy?
Progressive supranuclear palsy (PSP) is an
uncommon brain disorder that affects movement, control of walking (gait)
and balance, speech, swallowing, vision, mood and behavior, and
thinking. The disease results from damage to nerve cells in the brain.
The disorder’s long name indicates that the disease worsens (
progressive) and causes weakness (
palsy) by damaging certain parts of the brain above nerve cell clusters called nuclei (
supranuclear).
These nuclei particularly control eye movements. One of the classic
signs of the disease is an inability to aim and move the eyes properly,
which individuals may experience as blurring of vision.
Estimates
vary, but only about three to six in every 100,000 people worldwide, or
approximately 20,000 Americans, have PSP—making it much less common
than Parkinson's disease (another movement disorder in which an
estimated 50,000 Americans are diagnosed each year). Symptoms of PSP
begin on average after age 60, but may occur earlier. Men are affected
more often than women.
PSP was first described as a distinct
disorder in 1964, when three scientists published a paper that
distinguished the condition from Parkinson's disease. It was sometimes
referred to as Steele-Richardson-Olszewski syndrome, reflecting the
combined names of the scientists who defined the disorder.
Currently there is no effective treatment for PSP, but some symptoms can be managed with medication or other interventions.
What are the symptoms?
The pattern of signs and symptoms can be quite
different from person to person. The most frequent first symptom of PSP
is a loss of balance while walking. Individuals may have unexplained
falls or a stiffness and awkwardness in gait.
As the disease
progresses, most people will begin to develop a blurring of vision and
problems controlling eye movement. In fact, eye problems, in particular
slowness of eye movements, usually offer the first definitive clue that
PSP is the proper diagnosis. Individuals affected by PSP especially have
trouble voluntarily shifting their gaze vertically (i.e., downward
and/or upward) and also can have trouble controlling their eyelids. This
can lead to a need to move the head to look in different directions,
involuntary closing of the eyes, prolonged or infrequent blinking, or
difficulty in opening the eyes. Another common visual problem is an
inability to maintain eye contact during a conversation. This can give
the mistaken impression that the person is hostile or uninterested.
People
with PSP often show alterations of mood and behavior, including
depression and apathy. Some show changes in judgment, insight, and
problem solving, and may have difficulty finding words. They may lose
interest in ordinary pleasurable activities or show increased
irritability and forgetfulness. Individuals may suddenly laugh or cry
for no apparent reason, they may be apathetic, or they may have
occasional angry outbursts, also for no apparent reason. Speech usually
becomes slower and slurred and swallowing solid foods or liquids can be
difficult. Other symptoms include slowed movement, monotone speech, and a
mask-like facial expression. Since many symptoms of PSP are also seen
in individuals with Parkinson’s disease, particularly early in the
disorder, PSP is often misdiagnosed as Parkinson’s disease..
How is PSP different from Parkinson's disease?
Both PSP and Parkinson's disease cause stiffness,
movement difficulties, and clumsiness, but PSP is more rapidly
progressive as compared to Parkinson’s disease. People with PSP usually
stand exceptionally straight or occasionally even tilt their heads
backward (and tend to fall backward). This is termed “axial rigidity.”
Those with Parkinson's disease usually bend forward. Problems with
speech and swallowing are much more common and severe in PSP than in
Parkinson's disease, and tend to show up earlier in the course of the
disease. Eye movements are abnormal in PSP but close to normal in
Parkinson's disease. Both diseases share other features: onset in late
middle age, bradykinesia (slow movement), and rigidity of muscles.
Tremor, very common in individuals with Parkinson's disease, is rare in
PSP. Although individuals with Parkinson's disease markedly benefit from
the drug levodopa, people with PSP respond minimally and only briefly
to this drug. Also, people with PSP show accumulation of the protein
tau in affected brain cells, while people with Parkinson’s disease show accumulation of a different protein, called
alpha-synuclein.
What causes PSP?
The exact cause of PSP is unknown. The symptoms of
PSP are caused by a gradual deterioration of brain cells in a few
specific areas in the brain, mainly in the region called the brain stem.
One of these areas, the substantia nigra, is also affected in
Parkinson's disease, and damage to this region of the brain accounts in
part for the motor symptoms that PSP and Parkinson's have in common.
The
hallmark of the disease is the accumulation of abnormal deposits of the
protein tau in nerve cells in the brain, so that the cells do not work
properly and die. The protein tau is associated with microtubules –
structures that support a nerve cell’s long processes, or axons, that
transmit information to other nerve cells. The accumulation of tau puts
PSP in the group of disorders called the
tauopathies, which also
includes other disorders such as Alzheimer’s disease, corticobasal
degeneration, and some forms of frontotemporal degeneration. Scientists
are looking at ways to prevent the harmful clumping of tau in treating
each of these disorders.
PSP is usually sporadic, meaning that
occurs infrequently and without known cause; in very few cases the
disease results from mutations in the
MAPT gene, which then
provides faulty instructions for making tau to the nerve cell. Genetic
factors have not been implicated in most individuals.
There are
several theories about PSP's cause. A central hypothesis in many
neurodegenerative diseases is that once the abnormal aggregates of
proteins like tau form in a cell, they can affect a connected cell to
also form the protein clumps. In this way the toxic protein aggregates
spreads through the nervous system. How this process is triggered
remains unknown. One possibility is that an unconventional infectious
agent takes years or decades to start producing visible effects (as is
seen in disorders like Creutzfeldt-Jakob Disease). Another possibility
is that random genetic mutations, of the kind that occur in all of us
all the time, happen to occur in particular cells or certain genes, in
just the right combination to injure these cells. A third possibility is
that there is exposure to some unknown chemical in the food, air, or
water which slowly damages certain vulnerable areas of the brain. This
theory stems from a clue found on the Pacific island of Guam, where a
common neurological disease occurring only there and on a few
neighboring islands shares some of the characteristics of PSP,
Alzheimer's disease, Parkinson's disease, and amyotrophic lateral
sclerosis. Its cause is thought to be a dietary factor or toxic
substance found only in that area.
Another possible cause of PSP
is cellular damage caused by free radicals, which are reactive molecules
produced continuously by all cells during normal metabolism. Although
the body has built-in mechanisms for clearing free radicals from the
system, scientists suspect that, under certain circumstances, free
radicals can react with and damage other molecules. A great deal of
research is directed at understanding the role of free radical damage in
human diseases.
How is PSP diagnosed?
No specific laboratory tests or imaging approaches
currently exist to definitively diagnose PSP. The disease is often
difficult to diagnose because its symptoms can be very much like those
of other movement disorders, and because some of the most characteristic
symptoms may develop late or not at all. Initial complaints in PSP are
typically vague and fall into these categories: 1) symptoms of
disequilibrium, such as unsteady walking or abrupt and unexplained falls
without loss of consciousness; 2) visual complaints, including blurred
vision, difficulties in looking up or down, double vision, light
sensitivity, burning eyes, or other eye trouble; 3) slurred speech; and
4) various mental complaints such as slowness of thought, impaired
memory, personality changes, and changes in mood. An initial diagnosis
is based on the person’s medical history and a physical and neurological
exam. Diagnostic scans such as magnetic resonance imaging may show
shrinkage at the top of the brain stem. Other imaging tests can look at
brain activity in known areas of degeneration.
PSP is often
misdiagnosed because it is relatively rare and some of its symptoms are
very much like those of Parkinson's disease. Memory problems and
personality changes may also lead a physician to mistake PSP for
depression, or even attribute symptoms to some form of dementia. The key
to diagnosing PSP is identifying early gait instability and difficulty
moving the eyes, speech and swallow abnormalities, as well as ruling out
other similar disorders, some of which are treatable.
Is there any treatment?
There is currently no effective treatment for PSP,
although scientists are searching for better ways to manage the
disease. PSP symptoms usually do not respond to medications. Drugs
prescribed to treat Parkinson’s disease, such as ropinirole, rarely
provide additional benefit. In some individuals the slowness, stiffness,
and balance problems of PSP may respond to some degree to
antiparkinsonian agents such as levodopa, but the effect is usually
minimal and short-lasting. Excessive eye closing can be treated with
botulinum injections. Some antidepressant drugs may provide benefit
beyond treating depression, such as pain relief and decreasing drooling.
Recent
approaches to therapeutic development for PSP have focused primarily on
the clearance of abnormally accumulated tau in the brain. One ongoing
clinical trial will determine the safety and tolerability of a compound
that prevents accumulation of tau in preclinical models. Other studies
are exploring improved tau imaging agents that will be used to assess
disease progression and improvement in response to treatment.
Non-drug
treatment for PSP can take many forms. Individuals frequently use
weighted walking aids because of their tendency to fall backward.
Bifocals or special glasses called prisms are sometimes prescribed for
people with PSP to remedy the difficulty of looking down. Formal
physical therapy is of no proven benefit in PSP, but certain exercises
can be done to keep the joints limber.
A gastrostomy (a minimally
invasive surgical procedure that involves the placement of a tube
through the skin of the abdomen into the stomach for feeding purposes)
may be necessary when there are swallowing disturbances or the definite
risk of severe choking. Deep brain stimulation (which uses a surgically
implanted electrode and pulse generator to stimulate the brain in a way
that helps to block signals that cause many of the motor symptoms) and
other surgical procedures used in individuals with Parkinson's disease
have not been proven effective in PSP.
What is the prognosis?
The disease gets progressively worse, with people
becoming severely disabled within three to five years of onset. Affected
individuals are predisposed to serious complications such as pneumonia,
choking, head injury, and fractures. The most common cause of death is
pneumonia. With good attention to medical and nutritional needs, it is
possible for individuals with PSP to live a decade or more after the
first symptoms of the disease.
