Progressive
supranuclear palsy (PSP) is a rare brain disorder
that causes serious and permanent problems with control
of gait and balance. The most obvious sign of the
disease is an inability to aim the eyes properly,
which occurs because of lesions in the area of the
brain that coordinates eye movements. Some patients
describe this effect as a blurring. PSP patients often
show alterations of mood and behavior, including depression
and apathy as well as progressive mild dementia.
The
disorder's long name indicates that the disease begins
slowly and continues to get worse (progressive), and
causes weakness (palsy) by damaging certain parts of
the brain above pea-sized structures called nuclei that
control eye movements (supranuclear).
Approximately
20,000 Americans - or one in every 100,000 people over
the age of 60 - have PSP, making it much less common
than Parkinson's disease, which affects more than 500,000
Americans. Patients are usually middle-aged or elderly,
and men are affected more often than women. PSP is often
difficult to diagnose because its symptoms can be very
much like those of other, more common movement disorders,
and because some of the most characteristic symptoms
may develop late or not at all.
The
most frequent first symptom of PSP is a loss of balance
while walking. Other common early symptoms are changes
in personality such as loss of interest in ordinary
pleasurable activities or increased irritability, cantankerousness
and forgetfulness. Patients 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.
As
the disease progresses, most patients will begin to
develop a blurring of vision and problems controlling
eye movement. Speech usually becomes slurred and swallowing
solid foods or liquids can be difficult.
The
symptoms of PSP are caused by a gradual deterioration
of brain cells in a few tiny but important places at
the base of the brain, in the region called the brainstem.
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