Cerebral palsy or CP is a group of disorders associated with developmental brain injuries that occur during fetal development, birth, or shortly after birth. It is characterized by a disruption of motor skills, with symptoms such as spasticity, paralysis, or seizures. Cerebral palsy is a form of static encephalopathy and a form of it, called spastic diplegia, is sometimes called Little's disease. It is a chronic nonprogressive neurological disorder. The incidence is about 1.5 to 4 per 1000 live births. There is no cure, but therapy has been shown to be helpful to maintain, if not expand, motor functions. It has one of the highest lifetime costs of any congenital disability.
The disorder is marked by several important signs. All persons with cerebral palsy developed it while the brain was under development. This limits the age at which the disorder can develop to at most 5 years old, however 80% of all cases occur before the baby reaches 1 month old. Secondly, it is a nonprogressive disorder, that is, once the damage to the brain is done no additional damage occurs. Cerebral palsy never worsens, though its symptoms may seem to increase with time, due to the aging process. The disorder also never improves. It is a permanent disability which stays with a person for their entire life. Any temporary problems would suggest a disorder other than cerebral palsy, and more tests will have to be done. Additionally, the disorder is characterized by disruption of the motor skills of the person. The severity in the loss of motor skills varies greatly from case to case. Lastly, even though there is a loss of motor skills, the muscles themselves are not the problem. The problem lies solely in the brain's ability to control those otherwise healthy muscles.
Cerebral palsy, then known as "Cerebral Paralysis", was first identified by a British surgeon named William Little in 1860. Little raised the possibility of asphyxia during birth as a chief cause of the disorder. It was not until 1897 that Sigmund Freud suggested that a difficult birth was not the cause but rather only a symptom of other effects on fetal development. Modern research has shown that asphyxia is not found during birth in at least 75% of cases. Such research also shows that Freud's view was correct, even though during the late 19th century and most of the 20th century Little's view was the traditional explanation. ("Conditions", 9)
Since cerebral palsy refers to a group of disorders, there is no exact known cause. Some major causes are asphyxia or hypoxia of brain, birth trauma or premature birth, genetic susceptibility, certain infections in the mother during and before birth, central nervous system infections, trauma, and consecutive hematomas. In most people with CP, the cause is unknown. After birth, the condition may be caused by toxins, physical brain injury, incidents involving hypoxia to the brain (such as drowning), and encephalitis or meningitis. Despite all of these causes, the cause of many individual cases of cerebral palsy is unknown.
Recent research has demonstrated that asphyxia is not the most important cause as it was once considered to be, though it still plays a role, probably accounting for about 10% of all cases. The research has shown that infections in the mother, even infections that are not easily detected, may triple the risk of the child developing the disorder.
Premature babies have a higher risk because their organs are not yet fully developed. This increases the risk of asphyxia and other injury to the brain, which in turn increases the incidence of cerebral palsy.
Incidence and prevalence
The incidence is about 1.5 to 4 per 1000 live births. This amounts to approximately 5,000-10,000 babies born with cerebral palsy each year in the United States. Each year, around 1,500 preschoolers are diagnosed with the disorder. In around 70% of all cases, cerebral palsy is found with some other disorder, the most common being mental retardation.
Overall, advances in care of pregnant mothers and their babies has not resulted in a noticeable decrease in cerebral palsy. Only the introduction of quality medical care to locations with less than adequate medical care has shown any decreases. The incidence increases with premature or very low-weight babies regardless of the quality of care. Twins are also four times more likely to develop cerebral palsy than single births, and triplets are more likely still to develop it.
Despite medical advances, in some cases the incidence of cerebral palsy has actually increased over time. This may be attributed to medical advances in areas related to premature babies or the increased usage of artificial fertilization techniques.
Based on the group of muscles involved (typically only used to further describe spastic CP):
- Tetraplegia or Quadriplegia : Involvement of the four limbs, the trunk and the head. The great majority of these individuals will not be able to stand up or walk.
- Diplegia: The four limbs are affected, but lower limbs are more involved than upper limbs. Some of the people with diplegia will be able to walk alone or with orthosis.
- Hemiplegia: Only the right side or the left side of the body is involved. People with hemiplegia are the most likely to walk, even though people with the above two types can often walk without assistance, if severity allows.
NOTE: These are not the only 3 types of spastic CP. Occasionally, terms such as monoplegia, paraplegia, triplegia and pentaplegia may be used.
Ataxia: Persons with ataxia have damage to their cerebellum which results in problems with balance, especially while walking. It is the most rare type, occurring in at most 10% of all cases.
Athetoid or dyskinetic: Persons with this type generally have involuntary body movements. The damage occurs to the extrapyramidal motor system and/or pyramidal tract and to the basal ganglia. It occurs in ~20% of all cases.
Spastic: Persons with this type have damage to the corticospinal tract, motor cortex, or pyramidal tract. It occurs in ~70% of all cases.
These three types may be found together. In 30% of all cases of cerebral palsy, the spastic form is found with the one of the other types. There are a number of other minor types of cerebral palsy, but these are the most common.
Presentation (signs and symptoms)
All types of cerebral palsy are characterized by abnormal muscle tone, posture, reflexes, or motor development and coordination. The classical symptoms are spasticity, paralysis, seizures, unsteady gait, and dysarthria. While mental retardation and cerebral palsy do not cause each other, the two disorders are found together in approximately 20%-30% of all persons with cerebral palsy. CP symptomology is as diverse as the individuals who have it. Secondary symptoms can include rigidity of limbs, bladder control issues, and impaired tongue movement.
Cerebral Palsy is not a progressive disorder. A person with the disorder may improve somewhat during childhood, if they receive extensive care from specialists. Some individuals with the disorder will need to stay under the immediate care of another person for their entire lives, while others have a mild enough case to pursue fully independent lives.
There is no cure for cerebral palsy, but various forms of therapy can help a person with the disorder to function more effectively. Nevertheless, there is only some benefit from life-long care. The treatment is usually symptomatic and focuses on helping the person to develop as many motor skills as possible or to learn how to compensate for the lack of them. The disorder does not affect the expected length of life so treatment focuses on quality of life issues. Non-speaking people with cerebral palsy are often successful availing of Augmentative and Alternative Communication systems such as Blissymbols.
Usage of the term "spastic"
The term "spastic" describes the attribute of spasticity in one type of cerebral palsy. In 1952 a UK charity called The Spastics Society was formed. The term "spastic" was used by the charity as a term for people with cerebral palsy. This rapidly became used as a general insult to disabled people, and the charity changed its name to SCOPE in 1994.