Cerebral palsy is a group of disorders of movement and posture resulting from injury or malformation to the developing central nervous system. There are many causes for cerebral palsy, with onset ranging from preconception to an arbitrary point such as 24 months of age.
The neurologic impairment is non-progressive, although secondary disability can occur. Characteristics of cerebral palsy change with developmental stages, especially in the first few years of life. This impairment and resultant disability are both permanent.
‘Cerebral’ – refers to the brain. ‘Palsy’ – can mean weakness or paralysis or lack of muscle control. Therefore cerebral palsy is a disorder of muscle control which results from some damage to part of the brain. The term cerebral palsy is used when the problem has occurred early in life, to the developing brain.
What are the various types of cerebral palsy?
Spastic cerebral palsy
This is the most common type of cerebral palsy. Spasticity means stiffness or tightness of muscles. The muscles are stiff because the messages to the muscles are relayed incorrectly from the damaged parts of the brain.
When people without cerebral palsy perform a movement, groups of muscles contract whilst the opposite groups of muscles relax or shorten in order to perform the movement. In children with spastic cerebral palsy, both groups of muscles may contract together, making the movement difficult.
Dyskinetic cerebral palsy
This refers to the type of cerebral palsy with abnormal involuntary movements. It is divided into two types of movement problems, called dystonia and athetosis.
• Dystonia – this is the term used for sustained muscle contractions that frequently cause twisting or repetitive movements, or abnormal postures.
• Athetosis – this is the word used for the uncontrolled extra movements that occur particularly in the arms, hands and feet, and around the mouth. The lack of control is often most noticeable when the child starts to move – for example, when the child attempts to grasp a toy or a spoon. In addition, children with athetoid cerebral palsy often feel floppy when carried.
Ataxic cerebral palsy
This is the least common type of cerebral palsy. Ataxic (or ataxia) is the word used for unsteady shaky movements or tremor. Children with ataxia also have problems with balance.
Many children do not have just one type, but a mixture of several of these movement patterns.
How Is Cerebral Palsy Diagnosed?
The diagnosis of cerebral palsy is essentially clinical and is highly dependent on the physician’s knowledge of normal motor development and its variants. In all but the mildest cases, the diagnosis of cerebral palsy can be made by 12-18 months of age.
A thorough search for etiologies is warranted in the young child newly diagnosed with cerebral palsy. This includes a thorough history and physical, plus follow-up observation of the progression of motor abilities at frequent intervals. Physicians experienced with this disorder, such as developmental pediatricians, neurologists and geneticists, can be consulted to aid in the diagnosis.
To aid in confirming the diagnosis and ruling out neoplastic or progressive causes for motor disability such as metabolic and neurodegenerative disorders, magnetic resonance imaging (MRI) is usually indicated. The imaging can usually wait until a child can undergo the study without sedation or done in conjunction with another procedure.
Other diagnostic testing may include cultures, immune status, metabolic screening, karyotyping, genetic probes or confirmatory tests for other specific disorders. EEGs, EMGs and skull films are not useful for the diagnosis of cerebral palsy or its etiology.
What causes cerebral palsy?
Cerebral palsy occurs in about two in every thousand children. There are many different causes. A problem with the brain can occur:
1. If the brain does not grow or form properly. The result is that children may have brain malformations.
2. In the early months of pregnancy – for example, if the mother is exposed to certain infections such as Rubella (German Measles), or Cytomegalovirus (CMV).
3. During labour or at birth – for example, if the baby does not receive enough oxygen.
4. In the period shortly after birth – for example, when an infant develops a severe infection, such as meningitis, in the first few days or weeks of life.
5. In children having accidents in the early years of life, causing permanent brain injury. These children are also considered to have cerebral palsy.