Cerebral palsy is a non-progressive neurological disorder that affects body movement and muscle coordination. As of 2010, cerebral palsy affects approximately 800,000 children and adults in the United States, with approximately 10,000 new babies born with the condition each year, according to the National Institute of Neurologic Disorders and Stroke. Cerebral palsy occurs due to brain damage sustained during fetal development or just before, during or just after birth.
Cerebral Motor Cortex
As the name of the disorder suggests, cerebral palsy affects the cerebrum, the largest portion of the brain. The cerebrum controls voluntary movements, thinking, reasoning and emotions, as well as some specialized functions such as visual processing, speech and hearing. Damage often occurs to the cerebral motor cortex, a portion of the brain that lies at the back of the frontal lobe just before the fold that separates the frontal lobe from the parietal lobe, as described by the Canadian Institute of Neurosciences, Mental Health and Addiction.
The abnormalities in the cerebral motor cortex disrupt the brain’s ability to control both movement and posture. This results in the characteristic symptoms including a lack of muscle coordination, stiff or tight muscles, walking on the toes, muscles that appear too tight or too floppy, tremors and difficulty with precise movements. The severity of cerebral palsy varies depending on the extent of the damage to the cerebral motor cortex. Patients with mild cerebral palsy may exhibit slightly awkward movements, while severe cerebral palsy results in the inability to walk.
The brain consists of white matter, so called because it contains lots of nerve fibers sheathed in myelin--the fatty substance that surrounds and protects nerves--and the myelin appears white. The white matter contrasts with the gray matter, the majority of brain tissue, which appears gray because of the gray centers of the cells.
Although the gray matter processes the information in the brain, the white matter transmits the signals to the rest of the body. Some cerebral palsy occurs due to damage to the white matter, a condition known as periventricular leukomalacia--PVL. The damage in PVL looks like tiny holes in the white matter. The presence of these holes interrupts the transmission of nerve signals, resulting in the movement problems characteristic of cerebral palsy.
For many years, doctors believed most cases of cerebral palsy occurred due to complications during labor and delivery that caused a lack of oxygen to the baby’s brain resulting in brain damage. Today, however, due to research conducted by the National Institute of Neurologic Disorders and Stroke, doctors know that birth complications account for only approximately 5 to 10 percent of cerebral palsy cases.
Risk factors for cerebral palsy include low birth weight, premature birth and multiple births--since multiple births usually result in premature birth and low birth weight. A condition known as Rh incompatibility, which occurs when the mother’s blood type of positive or negative differs from the baby’s, increases the risk for cerebral palsy. Other risk factors include the exposure to toxic substances and abnormalities in the health of the mother, such as thyroid disease or mental retardation.