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Overview
The term cerebral palsy describes
not merely a single affliction, but an entire
spectrum of closely related chronic disorders
which appear in the first years of life, impair
the body's ability to control movement, and
usually do not worsen over time.
Cerebral refers to the cerebrum,
the upper part of the brain, composed of two
halves or hemispheres; palsy, a word descended
from Middle English and Latin roots related to
"paralysis," describes disorders that impair
control of body movement. Together, they form an
omnibus term for a variety of disorders in which
faulty development or damage to motor areas in the
brain disrupt its ability to control movement and
posture.
The symptoms of cerebral palsy (CP)
differ from person to person, and can change over
time. They can be as simple as having difficulty
with fine motor tasks like writing or using
scissors, or they may be as profound as an
inability to maintain balance or walk. The most
severely afflicted may have involuntary movements,
such as uncontrollable hand motions and drooling.
Others suffer from secondary or related medical
disorders, including seizures or mental
retardation. Some persons with severe CP might be
completely disabled and require lifelong care,
while others might display only a slight
awkwardness and need no special assistance.
Cerebral palsy is neither
contagious nor inherited. Although it cannot be
cured, science has made great strides in treating
and preventing it.
Incidence
It is estimated that more than half a million
Americans have CP, and an additional 4,500 infants
and children are diagnosed annually. These numbers
have remained remarkably constant over the past 30
years, in part because improvements in pre-natal,
pediatric and intensive care have enabled many
more critically premature and frail babies to
survive infancy than in the past. The downside of
this improvement is that many such children have
developmental disorders or suffer neurological
damage.
Symptoms
Doctors classify CP into four
categories: spastic, athetoid, ataxic and mixed
forms. These classifications reflect the type of
movement disturbance displayed by the patient.
Spastic CP
is the most common type. It afflicts somewhere
between half and three-quarters of all patients
with cerebral palsy, causing the muscles to be
stiff and permanently contracted. Doctors often
further subdivide spastic cerebral palsy into one
of five types, describing the limbs that are
affected. These names combine a Latin prefix
describing the affected limbs with the term plegia
(sometimes "paresis"), meaning paralyzed or weak:
-
diplegia
affects either both arms or both legs;
-
hemiplegia
affects the limbs on only one side of the body;
-
quadrapelgia
affects all the limbs;
-
monoplegia
affects only one limb; and
-
triplegia
affects three limbs.
Monoplegia and triplegia
are exceedingly rare, and are
mentioned here only in passing, so that a complete
picture of the affliction can be presented.
In persons with spastic diplegia
affecting the legs, the limbs often turn in and
cross at the knees. This causes a characteristic
walking rhythm known as scissors gait, in which
the legs move awkwardly and stiffly, nearly
touching at the knees.
Persons with spastic hemiplegia
(hemiparesis) also may experience hemiparetic
tremors - uncontrollable shaking of the limbs on
one side of the body - which, if severe enough,
can seriously impair movement.
About 10% to 20% percent of
patients have athetoid cerebral palsy (also called
dyskinetic cerebral palsy), which is characterized
by slow, uncontrolled, writhing movements of the
hands, feet, arms or legs. Some cases affect the
muscles of the face and tongue, causing grimacing
or drooling. The condition can affect the muscles
which control speech, a condition known as
dysarthria. Emotional stress can worsen the
movements, which usually vanish during sleep.
Ataxic cerebral palsy
is a rare form, affecting an estimated 5% to 10%
of CP patients. It affects the patient's balance
and depth perception. Persons with ataxic CP have
poor coordination. They walk unsteadily, usually
placing their feet far apart. Many have trouble
with quick or precise movements, like writing or
buttoning a shirt. Some also have intention
tremor, in which a voluntary movement, like
reaching for an object, sets off a trembling in
the limb which grows in intensity as the person
nears the target object.
Mixed CP
involves two or more types of cerebral palsy in
the same person. While any mix of types and
subtypes can occur, the most common are athetodic/spastic-diplegic
or athetoid/spastic-hemiplegic; the least common
is athetoid/ataxic. It is possible to have a mix
of all three types (spastic/athetoid/ataxic).
Experts estimate that mixed CP accounts for 10% of
all cases of cerebral palsy, although the actual
percentage may be higher.
Associated Disorders
Many persons with CP have no associated medical
disorders. However, some also have seizures and
impaired intellectual development, problems with
attentiveness, activity and behavior, and vision
and hearing.
Roughly a third of children with CP
also have mild intellectually impairment; another
third are moderately or severely impaired, and the
remainder are intellectually normal. Mental
impairment is most common in children with spastic
quadriplegia.
Up to half of all children with
cerebral palsy have
seizures,
in which uncontrolled bursts of electricity
disrupt the brain's normal pattern of electrical
activity. Seizures that recur without a direct
trigger, such as a fever, are classified as
epilepsy. Seizures generally take one of two
forms:
-
Tonic-clonic seizures are spread
throughout the brain, causing varied symptoms
all over the body. They typically cause the
patient to cry out and are followed by
unconsciousness, twitching of legs and arms,
convulsive body movements and loss of bladder
control.
-
Partial seizures are confined to
one part of the brain, and may be either simple
or complex. Simple partial seizures cause
localized symptoms - muscle twitches, chewing
movements and numbness or tingling. Complex
partial seizures can produce hallucinations,
staggering, random movements, impaired
consciousness or confusion.
Children with moderate-to-severe
cerebral palsy, especially those with spastic
quadriparesis, often experience a failure to grow
or thrive. Babies typically fail to gain weight
normally. Young children often appear abnormally
short. Teenagers may be unnaturally short for
their age, and their sexual development may be
unusually slow. These phenomena are thought to be
caused by a combination of poor nutrition and
damage to the brain centers that control growth.
Some patients, particularly those
with spastic hemiplegia, have muscles and limbs
that are smaller than normal. Limbs on the side of
the body affected by CP may grow slower than those
on other side. Hands and feet are most severely
affected. Scientists have noted that the affected
foot in cases of hemiplegia usually is the smaller
of the two, even among patients who walk,
suggesting the size difference is due not to lack
of use, but to disruption of the body's growth
process.
Vision and hearing
problems are more common among children
with cerebral palsy than those in the general
population. In many children with CP, differences
in the left and right eye muscles cause the eyes
are to be misaligned. This condition, called
strabismus, would normally would cause double
vision; in children, however, the brain often
adapts by ignoring signals from one eye. Because
strabismus can lead to poor vision and impaired
depth perception, some physicians recommend
corrective surgery.
Children
with hemiparesis may have hemianopia, a condition
marked by an impairment of the left or right
visual field in both eyes. A related condition
called homonymous hemianopia causes similar
impairment in identical spots in both eyes.
The ability to feel simple
sensations like touch or pain also may be impaired
in some children with CP. A child with
stereognosia, for example, might have difficulty
perceiving or identifying objects using the sense
of touch alone. To tell the difference between a
ball and a sponge placed in his or her hand, the
child would have to look at it.
Symptoms
Doctors classify CP into four
categories: spastic, athetoid, ataxic and mixed
forms. These classifications reflect the type of
movement disturbance displayed by the patient.
Spastic CP
is the most common type. It afflicts somewhere
between half and three-quarters of all patients
with cerebral palsy, causing the muscles to be
stiff and permanently contracted. Doctors often
further subdivide spastic cerebral palsy into one
of five types, describing the limbs that are
affected. These names combine a Latin prefix
describing the affected limbs with the term plegia
(sometimes "paresis"), meaning paralyzed or weak:
-
diplegia
affects either both arms or both legs;
-
hemiplegia
affects the limbs on only one side of the body;
-
quadrapelgia
affects all the limbs;
-
monoplegia
affects only one limb; and
-
triplegia
affects three limbs.
Monoplegia and triplegia
are exceedingly rare, and are
mentioned here only in passing, so that a complete
picture of the affliction can be presented.
In persons with spastic diplegia
affecting the legs, the limbs often turn in and
cross at the knees. This causes a characteristic
walking rhythm known as scissors gait, in which
the legs move awkwardly and stiffly, nearly
touching at the knees.
Persons with spastic hemiplegia
(hemiparesis) also may experience hemiparetic
tremors - uncontrollable shaking of the limbs on
one side of the body - which, if severe enough,
can seriously impair movement.
About 10% to 20% percent of
patients have athetoid cerebral palsy (also called
dyskinetic cerebral palsy), which is characterized
by slow, uncontrolled, writhing movements of the
hands, feet, arms or legs. Some cases affect the
muscles of the face and tongue, causing grimacing
or drooling. The condition can affect the muscles
which control speech, a condition known as
dysarthria. Emotional stress can worsen the
movements, which usually vanish during sleep.
Ataxic cerebral palsy
is a rare form, affecting an estimated 5% to 10%
of CP patients. It affects the patient's balance
and depth perception. Persons with ataxic CP have
poor coordination. They walk unsteadily, usually
placing their feet far apart. Many have trouble
with quick or precise movements, like writing or
buttoning a shirt. Some also have intention
tremor, in which a voluntary movement, like
reaching for an object, sets off a trembling in
the limb which grows in intensity as the person
nears the target object.
Mixed CP
involves two or more types of cerebral palsy in
the same person. While any mix of types and
subtypes can occur, the most common are athetodic/spastic-diplegic
or athetoid/spastic-hemiplegic; the least common
is athetoid/ataxic. It is possible to have a mix
of all three types (spastic/athetoid/ataxic).
Experts estimate that mixed CP accounts for 10% of
all cases of cerebral palsy, although the actual
percentage may be higher.
Associated Disorders
Many persons with CP have no associated medical
disorders. However, some also have seizures and
impaired intellectual development, problems with
attentiveness, activity and behavior, and vision
and hearing.
Roughly a third of children with CP
also have mild intellectually impairment; another
third are moderately or severely impaired, and the
remainder are intellectually normal. Mental
impairment is most common in children with spastic
quadriplegia.
Up to half of all children with
cerebral palsy have seizures, in which
uncontrolled bursts of electricity disrupt the
brain's normal pattern of electrical activity.
Seizures that recur without a direct trigger, such
as a fever, are classified as epilepsy. Seizures
generally take one of two forms:
-
Tonic-clonic seizures are spread
throughout the brain, causing varied symptoms
all over the body. They typically cause the
patient to cry out and are followed by
unconsciousness, twitching of legs and arms,
convulsive body movements and loss of bladder
control.
-
Partial seizures are confined to
one part of the brain, and may be either simple
or complex. Simple partial seizures cause
localized symptoms - muscle twitches, chewing
movements and numbness or tingling. Complex
partial seizures can produce hallucinations,
staggering, random movements, impaired
consciousness or confusion.
Children with moderate-to-severe
cerebral palsy, especially those with spastic
quadriparesis, often experience a failure to grow
or thrive. Babies typically fail to gain weight
normally. Young children often appear abnormally
short. Teenagers may be unnaturally short for
their age, and their sexual development may be
unusually slow. These phenomena are thought to be
caused by a combination of poor nutrition and
damage to the brain centers that control growth.
Some patients, particularly those
with spastic hemiplegia, have muscles and limbs
that are smaller than normal. Limbs on the side of
the body affected by CP may grow slower than those
on other side. Hands and feet are most severely
affected. Scientists have noted that the affected
foot in cases of hemiplegia usually is the smaller
of the two, even among patients who walk,
suggesting the size difference is due not to lack
of use, but to disruption of the body's growth
process.
Vision and hearing
problems are more common among children
with cerebral palsy than those in the general
population. In many children with CP, differences
in the left and right eye muscles cause the eyes
are to be misaligned. This condition, called
strabismus, would normally would cause double
vision; in children, however, the brain often
adapts by ignoring signals from one eye. Because
strabismus can lead to poor vision and impaired
depth perception, some physicians recommend
corrective surgery.
Children
with hemiparesis may have hemianopia, a condition
marked by an impairment of the left or right
visual field in both eyes. A related condition
called homonymous hemianopia causes similar
impairment in identical spots in both eyes.
The ability to feel simple
sensations like touch or pain also may be impaired
in some children with CP. A child with
stereognosia, for example, might have difficulty
perceiving or identifying objects using the sense
of touch alone. To tell the difference between a
ball and a sponge placed in his or her hand, the
child would have to look at it.
Causes
A small proportion of children who
have cerebral palsy - 10% to 20% - acquire it
after birth, typically from brain damage in the
first few months or years of life. In such cases,
the disorder may result from brain infections,
like bacterial meningitis or viral encephalitis,
or from head trauma sustained in an accident, fall
or from child abuse.
More baffling are the cause or
causes of congenital CP - the type that is present
at birth, although many cases go undetected for
months. While the cause of congenital CP often is
unknown, some specific events during pregnancy or
around the time of birth are known to damage motor
centers in the developing brain.
Infections during pregnancy, such
as German measles (rubella) can damage the
developing fetus's nervous system. Other
potentially damaging infections include
cytomegalovirus and toxoplasmosis.
Severe, untreated jaundice can
damage brain cells in newborns and infants. This
sometimes occurs during pregnancy when the
mother's body produces immune cells called
antibodies that destroy the fetus's blood cells, a
condition called Rh incompatibility.
Asphyxia, the deprivation of oxygen
to the brain, or trauma to the head during labor
or delivery also can caused CP. While the blood of
newborn infants is capable of compensating for low
oxygen levels during the stresses of labor and
delivery, severe asphyxia for a lengthy period can
produce a type of brain damage called
hypoxic-ischemic encephalopathy. Such damage
causes many infant deaths. Many surviving infants
are afflicted with CP, mental impairment and
seizures.
At one time, doctors and
researchers believed most cases of CP were
attributable to asphyxia or other complications
during birth. Today, it is known that such birth
complications are responsible for only about 3% to
13% percent of congenital CP cases.
Bleeding in the brain, can occur in
the fetus during pregnancy or in newborns around
the time of birth, damaging fetal brain tissue and
causing neurological problems, including
congenital CP. These hemmorhages are a type of
stroke that may be caused by broken, abnormal or
clogged blood vessels in or leading to the brain,
or by respiratory distress, a common breathing
disorder in premature infants.
Risk Factors
Certain characteristics are known
to increase the possibility that a child will
later be diagnosed with cerebral palsy. These
include:
-
Breech Presentation:
Babies who enter the birth canal at the
beginning of labor feet first, instead of head
first, are considered at risk of CP.
-
Labor and Delivery Complications:
A baby which experiences vascular or respiratory
problems during labor and delivery may be
displaying the first sign of brain damage or
abnormal brain development.
-
Physical Birth Defects:
Babies born with malformation of the spinal
bones, hernia in the groin area, or an
abnormally small jawbone are considered at risk
for CP.
-
Low Apgar Score:
As a means of assessing an infant's condition,
doctors check a baby's heart rate, breathing,
muscle tone, reflexes and skin color
periodically in the first minutes after birth.
Points are assigned for each function determined
to be normal. The result is an Apgar score: The
higher the score, the more normal the baby's
condition. Babies whose Apgar scores remain low
10 to 20 minutes after delivery are considered
to be at increased risk for health problems,
including CP.
-
Premature Birth/Low Birth Weight:
Babies born less than 37 weeks into pregnancy,
and those weighing under 2,500 grams (5 lbs., 7
1/2 oz.) have the highest risk of CP. Risk
increases as birth weight falls.
-
Multiple Births:
There is an increased risk of CP in repeated
deliveries of twins, triplets and other multiple
births.
-
Nervous System Malformations:
Babies born with an abnormally small head (microcephaly)
often have nervous system malformations, such as
CP.
-
Complications in the Mother:
Mothers who experience vaginal bleeding after
the sixth month of pregnancy, and those and who
have excess proteins in their urine are at high
risk of having infants with CP, as are those who
have hyperthyroidism, mental retardation or
seizures.
-
Newborn Seizures:
Infant who have seizures are at risk of being
diagnosed later with CP.
Prevention
The best prescription for having a healthy baby is
to have regular prenatal care and good nutrition,
and to avoid smoking, alcohol consumption and drug
abuse. A pregnancy marked by these conditions is
less likely to result in birth complications and
congenital problems in the newborn.
In addition, doctors recommend
several other forms of prevention and treatment
with respect to CP. These include:
-
Prevent head injuries
by using child safety seats in automobiles and
helmets when riding bicycles, skateboards, etc.
Supervise young children closely during bathing
and swimming. Prevent child abuse. Keep poisons
out of reach.
-
Treat jaundice in newborns with
phototherapy.
Exposing jaundiced babies to special blue lights
that break down bile pigments and prevent them
from building up can avoid damage to the brain.
In rare cases, special blood transfusions may be
necessary.
-
Identify potential Rh
incompatibility
in expectant mothers and, if indicated, fathers.
The incompatibility of blood Rh factors usually
is not problematical with first pregnancies, as
the mother's body typically produces the
unwanted antibodies only after delivery. A
special serum given after each childbirth can
prevent the unwanted production of antibodies.
If a woman develops the antibodies during her
first pregnancy, or if antibody production is
not prevented, doctors can watch the developing
baby closely and, if necessary, either perform a
transfusion to the baby in the womb, or by means
of an exchange transfusion after birth, removing
and replacing a large volume of the baby's
blood.
-
Be vaccinated against rubella
(German measles) before becoming
pregnant.
Treatment
There is no cure for cerebral
palsy, but treatment can improve a child's
capabilities. CP patients whose neurological
problems are properly managed can enjoy
near-normal lives. Every patient is different,
however, and no single therapy works equally well
for everyone. The key is to identify each
patient's specific needs and problems, and to
develop an individualized treatment plan to
address them. Often this is best accomplished by
teamwork, with health care professionals from
various disciplines working together. A typical
treatment team might include:
-
a pediatrician,
pediatric neurologist or a pediatric physiatrist
to synthesize and distill input all team members
into a comprehensive treatment plan, and to
follow the patient's progress over time;
-
an orthopedist
or orthopedic surgeon to predict, diagnose and
treat any associated muscle, tendon and bone
problems;
-
a physical therapist
to design and supervise any special exercise
programs necessary to improve the patient's
movement and strength;
-
an occupational therapist
to help the patient learn life skills for home,
school and work;
-
a speech/language pathologist
to diagnose and treat any identified
communication problems;
-
a social worker
to help patients and their families obtain
community assistance, education and training
programs; and
-
a psychologist
to oversee therapy, help address any unhelpful
or destructive behaviors, and guide the patient
and his/her family through the inevitable
stresses and demands presented by cerebral
palsy.
It is imperative that patients,
families, teachers and caregivers should be
involved in all phases of planning, decision
making and treatment.
Physical Therapy
Therapy is an essential element of any cerebral
palsy treatment program. Depending upon the
patient's deficits, physical therapy may address
movement, speech or practical skills. As the
patient ages and develops - mentally as well as
physically - his or her needs also will change.
Accordingly, therapy should be adjusted to reflect
these new demands.
It is important for physical
therapy to begin early in life, preferably soon
after diagnosis is made. It will incorporate
exercises to prevent muscles from growing weak and
atrophied, or rigidly fixed through contracture.
Of these two complications,
contracture is the more common and potentially
serious. Normal growth stretches muscles and
tendons, causing them to grow at the same rate as
the body's bones. The spasticity that often
characterizes CP can prevent this stretching,
however, and muscle growth may be insufficient to
keep up with that of bones as they grow longer.
This can cause muscles to become fixed in stiff,
abnormal positions, disrupting balance and causing
the loss of physical abilities. Physical therapy,
often in combination with special braces, seeks to
prevent contracture by stretching the spastic
muscles. It also can improve a child's motor
development.
From this early emphasis on motor
development, therapy will begin to incorporate
measures that prepare a child for school. The
focus will gradually shift toward activities
associated with daily living and communication.
Exercises will be aimed at improving the child's
ability to sit, move about independently and
perform tasks such as writing. Mastering such
skills reduces demands on caregivers and enhances
the child's self-reliance and self-esteem. An
occupational therapist can help the child learn to
feed and dress himself, or use the bathroom. A
speech therapist can work with the child to
identify specific communication problems and learn
to use special communication devices like
computers with voice synthesizers.
Behavioral therapy can complement
physical therapy, employing psychological
techniques which encourage the mastery of tasks
that promote muscular and motor development.
Praise, positive reinforcement and small rewards
can encourage a child to learn to use weak limbs,
overcome speech deficits or stop negative
behaviors like hair-pulling and biting.
The need for and types of therapy
typically continue to change throughout life. As
the child with CP grows into adolescence,
counseling for emotional and psychological
challenges may be necessary. Physical therapy may
need to be supplemented by special education,
vocational training, recreation and leisure
programs. By the time the child reaches adulthood,
he or she may benefit from attendant care, special
living accommodations, transportation or
employment assistance services, depending upon his
or her intellectual and physical capabilities.
Drug Therapy
When CP is accompanied by seizures, some form of
drug therapy usually is necessary. A variety of
drugs, prescribed either individually or in
combination, is available to help the patient
achieve good seizure control. No single drug
controls all types of seizures, however, and no
two patients are guaranteed to respond identically
to any given drug. As with many forms of drug
therapy, a certain amount of experimentation may
be required before optimum results are achieved.
For instance, the effectiveness of the anti-spasticity
drug baclofen might be enhanced by administering
it through spinal injections, rather than orally.
The use of minute implanted pumps to deliver a
steady supply of antispasticity drugs into the
fluid around the spinal cord also may used to help
control spacticity.
Other drugs can be prescribed to
control spasticity. These include diazepam, a
general brain and body relaxant, and dantrolene,
which work to control muscle contraction. Although
these drugs reduce spasticity for short periods,
their long-term value is uncertain. Side effects
like drowsiness can be a problem, and their
long-term impact on a child's developing nervous
system is unknown.
Doctors may prescribe other drugs -
the so-called anticholinergics - to control the
abnormal movements associated with athetoid
cerebral palsy. These drugs work to control the
effects of acetylcholine, a chemical in brain
cells that can trigger muscle contraction. The
most commonly prescribed anticholinergic drugs are
trihexyphenidyl, benztropine and procyclidine
hydrochloride.
In some cases physicians may try to
reduce spasticity or correct a developing
contracture by injecting phenol into a muscle that
is too short. This weakens the muscle and gives
physicians and therapists a chance to stretch and
lengthen the muscle with therapy, bracing or
casts. If the contracture is addressed early
enough, the need for surgery may be avoided.
Surgery
If contractures cause severe movement problems,
surgery to lengthen muscles and tendons may be
recommended. Identifying the appropriate muscles
to correct can be difficult, however, because many
muscles are often involved in a single action,
such as walking, and the body tends to compensate
for muscles that function poorly. To pinpoint
problem muscles, eliminate compensation factors
associated with walking and check surgical
results, doctors use a technique called gait
analysis. This technique uses cameras and
computers to record and analyze each portion the
patient's walk, along with special recording
equipment that detects electrical activity within
the muscles.
Surgically lengthening a muscle
makes it weaker, and usually necessitates months
of recovery. Whenever possible, therefore, doctors
try to fix affected muscles with a single surgery.
If more than one procedure is required, operations
usually are scheduled as close together as
possible.
Other Surgical Techniques
Dorsal root rhizotomy is a surgical technique used
to treat spasticity in the legs by selectively
severing nerves that over-stimulate leg muscles.
Although the procedure is controversial, results
suggest it can hold benefits for some CP patients,
particularly those with spastic diplegia.
Chronic cerebellar stimulation is
an experimental technique that uses electrodes
surgically implanted on the surface of the
cerebellum - the part of the brain that
coordinates movement - to decrease spasticity and
improve motor function by stimulating certain
nerves. Some studies claim the procedure improves
spasticity, while others report less satisfactory
results.
Another experimental technique,
stereotaxic thalamotomy, involves cutting parts of
the thalamus, the brain's center for relaying
messages from the muscles and sensory organs.
Studies show it can reduce some hemiparetic
tremors.
Treating Complications
Incontinence, caused by faulty control over the
bladder muscles, can be treated with exercises,
biofeedback, prescription drugs, surgery or
surgically implanted devices that replace or aid
muscles.
Drooling, caused by poor
functioning of the muscles of the throat, mouth
and tongue, can be more difficult to control.
Anticholinergic drugs reduce the flow of saliva,
but may produce side effects like mouth dryness
and poor digestion. Surgery sometimes helps, but
also can worsen swallowing problems. Biofeedback
has been proven helpful in patients who are
intellectually unimpaired and motivated.
Eating and swallowing problems may
require the caregiver to prepare food in a
semisolid fashion, such as strained vegetables and
fruits. Physical therapy can support and promote
proper positioning while eating or drinking, or
help extend the neck away from the body to reduce
the risk of choking. Severe swallowing problems
may necessitate the use of a tube to deliver food
down the throat and into the stomach. A more
invasive practice called gastrostomy is sometimes
necessary. It involves making a surgical opening
in the abdomen that allows tube-feeding directly
into the stomach. |
