What is Cerebral Palsy?
Cerebral palsy (CP) is a term used to describe a group of related movement disorders caused damage to the developing brain of a baby during pregnancy or childbirth. The damage affects areas of the brain involved with controlling and coordinating movement and balance, resulting in physical disabilities. The base word palsy means weakness or inability and cerebral refers to the brain.
Cerebral palsy is a disorder that has been recognized for hundreds of years. The earliest known description of cerebral palsy as an acknowledged medical condition dates back 2,500 years to medical texts from ancient Greece. The disorder was first given the name "cerebral palsy" in the late 1800s by one of the founders of the prestigious Johns Hopkins Medical School.
Today, cerebral palsy is the most common cause of physical disabilities in children in the world. The National Institute of Health (NIH) estimates that for every 1,000 babies born in the U.S., 3.5 will be diagnosed with cerebral palsy. According to the Cerebral Palsy Guidance, around 10,000 babies are born each year in the US with cerebral palsy. Approximately 1 in 323 people in the U.S. are currently living with cerebral palsy.
Cerebral palsy is caused by damage to the brain during a specific window of time when the brain is still developing during pregnancy or infancy. Although this type of injury to the developing brain triggering CP can theoretically occur anytime in the first 2 years of life, it almost always happens during pregnancy or childbirth.
The brain requires a continuous supply of blood and oxygen to survive. During pregnancy and childbirth the circulation of oxygenated blood to the baby's brain is particularly vulnerable to interruption. When oxygen to the baby's brain is disrupted (even for a short time) cells in the cerebral cortext are of the brain begin to die. The cerebral cortext is area within the brain that controls body movement and coordination. Injury to this area of the brain during this early developmental stage causes unique problems with how the brain communicates with the muscles in the body. The normal signals from the brain become distorted and it is not able to control movement like it normally would.
Children with cerebral palsy are affected differently depending on the specific nature and extent of the brain injury. Some children with CP may be disabled on just one side of their body or in the upper body only, whereas others will be affected over their entire body.Types of Cerebral Palsy
There are 4 recognized types of cerebral palsy which differ based on the type of muscle control issues and what areas of the body are impacted:
- Spastic - Spastic cerebral palsy is the most widespread type of CP. Somewhere between 77-81% of all cerebral palsy cases are classified as spastic CP. The characteristic symptom of spastic CP is extreme muscle stiffness (hypertonia) affecting a specific area of the body. So the dyskinetic has a significant problem with involuntary movements mixed whereas the spastic CP is the tightness of muscle tone. Spastic CP is divided into subtypes depending on the specific section of the body that is impaired by muscle stiffness:
- Diplegia: hypertonia impairs the lower body (legs and feet) only while the upper body is usually not affected
- Hemiplegia: only one particular side of the body (left or right) is impaired by muscle stiffness with the upper body more affected than the lower
- Quadriplegia: hypertonia impairs the entire body - upper and lower and left and right sides
- Dyskinetic - Dyskinetic is a form of CP in which there are typically involuntary movements that come under that umbrella. They may be twisting, they may be tremors, or they may have a ombination of tremors and twisting. But basically the dyskinetic has a significant problem with involuntary movements mixed in; whereas, the spastic variety, these basically refer to tightness of muscle tone. With dyskinetic cerebral palsy children suffer from a combination of both excessive muscle stiffness and spasticity (hypertonia) and lack of muscle tone or floppy muscles (hypotonia). This often leads to slow, involuntary movements of muscles in the arms and legs. Sometimes the face and mouth are also affected. Dyskinetic CP is the second most common type of CP.
- Ataxic - This is the least common type of cerebral palsy, accounting for less than 5% of all cases. Children who have ataxic cerebral palsy are impaired by severe lack of balance and movement coordination. This is particularly evident when attempting fine motor movements like writing. Ataxic CP can also cause difficulty with walking. Ataxic CP can affect the entire body and may also result in difficulties with speech or swallowing.
- Mixed - A small percentage of children with cerebral palsy are impairment by a combination of the different subtypes. This is called mixed cerebral palsy. The most common combo in cases of mixed CP is spastic-dyskinetic.
Cerebral palsy is not actually a singular disease, but rather an diverse condition including a grouping of related neurologic disorders impairing body movement. This means that the outward symptoms and effects of cerebral palsy will be very different in each individual child. Not only are there different types of CP, each with its own unique symptoms, but there is also a wide spectrum of severity. So even with the same type of cerebral palsy, actual physical symptoms and disabilities will vary greatly between moderate and severe cases.
- I. Novak, C. Morgan, L. Adde, et al. Early, Accurate Diagnosis and Early Intervention in Cerebral Palsy – Advances in Diagnosis and Treatment. JAMA Pediatr. 2017 Vol 171(9), 897-907.
- O. Verschuren, M. Peterson, A. Balemans, E. Hurvitz. Exercise and physical activity reccomendations for people with cerebral palsy. Dev Med Child Neurol. 2007 Feb.; 49(2), 2016-2032.
- K. Nelson and J. Ellenberg. Antecedents of Cerebral Palsy. N Engl J Med 1986; 315:81-86.
- A. Eliasson, L. Krumlinde-Sundholm, Birgit Rosblad, E. Beckung, et al. The Manual Ability Classification System (MACS) for children with cerebral palsy: scale development and evidence of validity and reliability. Dev Med Child Neurol. 2006 July 48:7, 549-554.
- DH Sutherland & J. Davis. Common gait abnormalities of the knee in cerebral palsy. Clinical Orthopedics and Related Research. 01 Mar 1993(288): 139-147.