By Lee Vanderloop
Spastic cerebral palsy is the most common form of cerebral palsy, occurring in 50-75% of all cases. People with spastic cerebral palsy have too much muscle tone or tightness, a condition called hypertonia. Their movements are stiff and jerky, especially in the legs, arms, and back.
Sometimes an infant born with weak muscle tone, called hypotonia, will progress to hypertonia after the first 2 to 3 months of life. Children with cerebral palsy may exhibit unusual posturing or favor one side of the body when they move.
Up to 80% of all people with cerebral palsy suffer from some degree of spasticity. Spastic cerebral palsy is further categorized by what parts of the body are affected. In spastic diplegia, the main effect is found in both legs. Spastic hemiplegia involves one side of the person’s body. Spastic quadriplegia affects a person’s whole body (face, trunk, legs, and arms).
A person can have spastic cerebral palsy so mild that walking can simply look awkward, or be so severe that the use of a wheelchair is required.
Causes of Spastic Cerebral Palsy
According to the National Institutes of Health, four types of brain damage cause the characteristic symptoms of cerebral palsy:
- Damage to the white matter of the brain (periventricular leukomalacia [PVL]). The white matter of the brain is responsible for transmitting signals inside the brain and to the rest of the body. Periventricular leukomalacia describes a type of damage that looks like tiny holes in the white matter of an infant’s brain. These gaps in brain tissue interfere with the normal transmission of signals. There are a number of events that can cause PVL, including maternal or fetal infection. Researchers have also identified a period of selective vulnerability in the developing fetal brain between 26 and 34 weeks of gestation. During this time, periventricular white matter is particularly sensitive to injury.
- Abnormal development of the brain (cerebral dysgenesis). Any interruption of the normal process of brain growth during fetal development can cause brain malformations that interfere with the transmission of brain signals. The fetal brain is particularly vulnerable during the first 20 weeks of development. Mutations in the genes that control brain development during this early period can keep the brain from developing normally. Infections, fevers, trauma, or other conditions that cause unhealthy conditions in the womb also put an unborn baby’s nervous system at risk.
- Bleeding in the brain (intracranial hemorrhage). Intracranial hemorrhage involves bleeding inside the brain caused by blocked or broken blood vessels. A common cause of this kind of damage is fetal stroke. Some babies suffer a stroke while still in the womb because of blood clots in the placenta that block blood flow. Other types of fetal stroke are caused by malformed or weak blood vessels in the brain or by blood-clotting abnormalities. Maternal high blood pressure (hypertension) is a common medical disorder during pregnancy that has been known to cause fetal stroke. Maternal infection, especially pelvic inflammatory disease, has also been shown to increase the risk of fetal stroke.
- Brain damage caused by a lack of oxygen in the brain (hypoxic-ischemic encephalopathy or intrapartum asphyxia). Asphyxia, a lack of oxygen in the brain caused by an interruption in breathing or poor oxygen supply, is common in babies due to the stress of labor and delivery. But even though a newborn’s blood is equipped to compensate for short-term low levels of oxygen, if the supply of oxygen is cut off or reduced for lengthy periods, an infant can develop a type of brain damage called hypoxic-ischemic encephalopathy, which destroys tissue in the cerebral motor cortex and other areas of the brain. This kind of damage can also be caused by severely low maternal blood pressure, rupture of the uterus, detachment of the placenta, or problems involving the umbilical cord.
How Movement is Affected
The type of brain damage that leads to cerebral palsy affects movement. Movement is governed by muscle tone, which is the continuous and passive amount of tension in a muscle that allows us to change or keep certain postures.
Healthy muscles work in groups. For example, when you bend your arm, the group of muscles on the front of your arm contract and the muscles on the back of your arm relax, which is what allows the bend to occur. Except in deep sleep, our muscles are in a constant state of active or passive tension, which allows us to do things like sit up, raise our heads, or stand.
Our brain sends out signals to muscles telling which ones to contract and which to extend to make our movements smooth and controlled. When any movement occurs, there are two sets of muscles working around a joint. Normally, the muscles on one side of the joint must relax so that the muscles on the other side can contract. In people with spastic cerebral palsy, the brain activates muscles at the same time, causing muscle groups to work against each other. The result is stiff, jerky movements.
Symptoms of Spastic Cerebral Palsy
Brain damage can occur before an infant is born, during labor and delivery, or when a child is older as the result of illness, accident, or injury. If the damage occurred before or during birth, an infant might have low APGAR scores, floppy muscle tone, poor color, weak breathing, the inability to suck, and development of seizures. In less severe cases, brain injury may not be obvious until the child fails to meet developmental milestones. In most cases, children with cerebral palsy are diagnosed by age three. Your child’s physician may order a brain scan or MRI for the diagnosis of cerebral palsy. This study may show lesions or other possible suspected causes of spastic cerebral palsy.
Following are some symptoms of spastic cerebral palsy in children:
Contractures-Contractures are “frozen joints,” and occur when a limb cannot be stretched or moved (when another person tries to moves it about its joint). Contractures may develop because the muscles were shortened or wasted away (atrophy), or from the development of scar tissue (fibrosis) formed over the joints.
Clonus –Clonus is a movement characterized by rapid, alternate contractions and relaxations of a muscle. Clonus is frequently observed in conditions such as spasticity and certain seizure disorders. A child with spastic cerebral palsy may experience episodes of clonus when trying to walk or navigating stairs. Clonus may cause the child’s foot to move up and down uncontrollably or shake erratically. In the case of clonus involving the arms, an attempt at controlled movement may trigger rapid, violent tremors or shaking of the arms and hands, sometimes leading to violent scissoring of the arms, possibly banging of the fists together.
Dystonia-Dystonia is a movement disorder characterized by lasting muscle tightening or contractions. The contractions result in repeated twisting or writhing movements and unusual postures or positioning that the person with dystonia cannot control. This disorder may be limited to specific muscle groups and may result from the use of certain medications.
Exaggerated deep tendon reflexes-Knee jerk and other reflexes may be exaggerated.
Exaggerated startle reflexes and hypersensitivity-Infants may seem particularly sensitive to their environment, such as noise and light. They may seem especially sensitive to touch, startling easily and becoming fussy when stroked or held.
Hip dysplasia and dislocation-Hip dysplasia and dislocation is a common feature of cerebral palsy. The hip joint is normal at birth but the spastic muscle imbalance and lack of weight bearing leads to the development of progressive structural changes around the hip joint. These deformities contribute to hip dysplasia and dislocation. The consequences of a hip dislocation include difficulty with toileting and hygiene and result in problems with sitting.
Myoclonus-Myoclonus is a neurological movement disorder characterized by brief, involuntary, twitching or “shock-like” contractions of a muscle or muscle group. Depending on its cause, the muscle jerks can occur repeatedly or infrequently. They also may tend to occur only during specific circumstances. The muscle jerks can affect any body region or regions.
Muscle spasms or scissoring-Involuntary crossing of the legs or arms.
Categories of Spastic Cerebral Palsy
Spastic Diplegia-Spastic Diplegia is spastic cerebral palsy that may involve both legs, causing difficulty with walking due to tight muscles in the hips and legs causing legs to turn inward and cross at the knees (scissoring).
Spastic Hemiplegia-Spastic hemiplegia affects one side of the body. In the brain, one hemisphere (side) controls the opposite side of the body. So, if the left side of the brain experiences damage, the symptoms will appear on the right side of the body and vise versa.
Spastic Quadriplegia-Spastic quadriplegia is spastic cerebral palsy that involves all four limbs and the trunk, often along with the muscles controlling the mouth and tongue and also those controlled by the autonomic system responsible for swallowing, gastric emptying, and intestinal motility. This is the most severe form of spastic cerebral palsy.
Treatment for spastic cerebral palsy focuses on controlling excess tone and spasticity by means of medication, surgery or spinal cord stimulation, alleviating pain, and providing regular physical therapy. Failure to control excess tone and spasticity to the extent possible can lead to contractures, scoliosis, and hip dysplasia, and it may severely impact quality of life.
- Benzodiazepines–A class of medications that act upon the central nervous system to reduce communication between certain neurons, lowering the level of activity in the brain. Benzodiazepines are muscle relaxants such as diazepam, oral baclofen, and dantrolene and are frequently the first line of treatment in managing movement disorders.
- Intrathecal baclofen–Approved by the Food and Drug Administration (FDA) in 1996 for treatment of cerebral palsy, this therapy is becoming the common choice of treatment in movement disorders that do not respond well to other forms of treatment. This form of therapy uses an implanted pump device to deliver baclofen (muscle relaxant) into the spinal cord. This form of therapy is most appropriate for children with severe hypertonia and uncontrolled movement disorders throughout the body.
- Orthopedic surgery is often recommended when spasticity and stiffness are severe enough to make walking and moving difficult or painful. Commonly, surgery involves lengthening muscles and tendons that are proportionately too short. Orthopedists generally time surgeries to coincide with a specific stage of the child’s physical development.
- Spasticity in the upper leg muscles, which causes a “scissor pattern” walk, is a major obstacle to normal gait. The optimal age to correct this spasticity is 2 to 4 years of age with adduction release surgery. On the other hand, the best time to perform surgery to lengthen the hamstrings or Achilles tendon is 7 to 8 years of age. If adduction release surgery is delayed so that it can be performed at the same time as hamstring lengthening, the child will have learned to compensate for spasticity in the adductors. By the time the hamstring surgery is performed, the child’s abnormal gait pattern could be so ingrained that it might not be easily corrected. With shorter recovery times and new, less invasive surgical techniques, doctors can schedule surgeries at times that take advantage of a child’s age and developmental abilities for the best possible result.
- Selective dorsal rhizotomy (SDR) is a surgical procedure recommended only for cases of severe spasticity when all of the more conservative treatments have proven ineffective. In this procedure, surgeons locate and selectively sever over-activated nerves at the base of the spinal cord to reduce spasticity in the legs.
Spinal Cord Stimulation
Spinal Cord Stimulation was developed in the 1980s to treat spinal cord injury and other neurological conditions involving motor neurons. This procedure involves an implanted electrode, which selectively stimulates nerves at the base of the spinal cord to inhibit and decrease nerve activity. The effectiveness of spinal cord stimulation for the treatment of cerebral palsy has yet to be proven in clinical studies. It is considered only when other conservative or surgical treatments have been unsuccessful at relaxing muscles or relieving pain.
Deep Brain Stimulation
Deep Brain Stimulation involves placing thin wires through tiny holes in the skull into the area of the brain that controls movements. The leads are then connected to a device called a neurostimulator. The device sends electrical pulses or signals to areas deep within the brain. These signals block the abnormal nerve signals causing the symptoms of dystonia. Research hospitals such as Children’s Hospital of Pittsburgh and the University of California, San Francisco have reported benefits for children with cerebral palsy from deep brain stimulation.
A growing body of research supports the use of Botox injections for easing spasticity in children with cerebral palsy. However, the FDA has not approved Botox for this purpose because of possible dangerous side effects. A board certified neurosurgeon should administer this treatment, which gives only temporary relief.
The prognosis for those with spastic cerebral palsy depends on the severity of the spasticity and the nature and severity of the brain damage. Spastic cerebral palsy does not always involve seizures or profound disabilities, developmental delays, or learning disabilities. While one child with severe spastic cerebral palsy might be developmentally delayed and unable to walk and need lifelong care, another with mild cerebral palsy might only have a few awkward movements, exhibit no developmental delays, and require no special assistance.
The degree of spasticity can vary from mild muscle stiffness to severe, painful, and uncontrollable muscle spasms, and can interfere with rehabilitation. It can often interfere with daily activities and may also result in feeding, swallowing, speech and oral motor difficulties, as well as disrupted or increased muscle tone of the gastric and intestinal muscles, putting a child at risk of reflux (Gastro esophageal reflux disease – GERD) and delayed gastric emptying. Unchecked, spasticity can severely impact a child’s physical and cognitive development.
Some children may require only augmentative communication and adaptive equipment to be active and functional, while others may require a lifetime of therapy, surgeries, and medications. Children with severe spastic cerebral palsy may also be at increased risk of aspiration pneumonia and scoliosis. Depending on the severity, a child may also be diagnosed with “failure to thrive” because of the high amount of energy and calories the body uses in cases of chronic spasticity.
Spastic cerebral palsy provides life-long challenges. But with the help of medications, therapy and continuing advancements in medical care, it can be managed to provide the fullest life possible. For more information and support for families dealing with cerebral palsy, go to www.cpfamilynetwork.org.
National Institute of Neurological Disorders and Stroke Spasticity Information Page.