To diagnose cerebral palsy (CP), a pediatrician or pediatric neurologist will perform a complete physical examination and medical history, paying attention to prenatal development, birth and the mother’s health status during the pregnancy. A neurological examination will also be used to diagnose the condition.

During well-baby checkups (these occur at 2, 4, 6, 9 and 12 months of age), the physician performs a visual examination of the baby and checks the ability to move the neck, hands, feet, arms and legs. The physician also rotates the baby’s legs to check for hip dislocation. In addition, the physician will check several basic responses and reflexes, such as a startle response, to assess the baby’s development.

The checkups will also focus on assessing the child’s motor, speech and language and neurological (nervous system) development. The physician will focus on basic skills such as rolling over, sitting up and standing as well as the use of sounds and words.

During the examination at 12 months, the physician will inspect a child’s feet and observe the child’s gait to make sure the bones in the legs and feet are normal. The physician will assess the child’s basic motor movements, such as grasping and clapping, to determine if there are any difficulties. The physician will discuss the child’s communication skills with the parent, including the child’s ability to understand and whether or not the child is speaking. In addition, the physician will examine the child’s ears for any signs of infection and mouth for the presence of teeth.

The physician will also evaluate the child’s ability to visually track or follow objects (e.g., vision test) and generally assess the child’s hearing.

In addition to the medical history, neurological and physical examination, the physician may also order diagnostic tests for the child. These may include:

• X-ray. A painless test in which an image is created of part of the body by using low doses of radiation that are reflected on film paper or fluorescent screens. An x-ray is effective at diagnosing skull fractures, although it is less effective at diagnosing specific problems within the brain. For this purpose, a computed axial tomography (CAT) scan or magnetic resonance imaging (MRI) may be used.

• CAT scan. A noninvasive or minimally invasive test that uses a rotating x-ray device to create three-dimensional cross-sectional images (or slices) of different body parts, including the brain and skull. CAT scans can be used to diagnose numerous conditions and complications which may arise from a head injury, such as blood clots and skull fractures. They can also be used to guide a biopsy.
  
  
• MRI. A noninvasive procedure that uses powerful magnets and radio waves to produce clear, cross-sectional or three-dimensional images of body tissues. A certain type of MRI is particularly useful in cases of head injuries because of the ability to assess how the brain is functioning. This type of MRI is called a functional MRI (fMRI). During an fMRI, the patient may be asked to perform a task while the machine scans the brain and records its activity. This information can then be used to determine which parts of the brain may be damaged.
  
  
• Blood test. A sample of blood is drawn from the newborn’s heel or the veins in the arm of older children. These tests can determine possible chromosomal and genetic reasons for the child’s condition.
  
  
• Urine test. A sample of the child’s urine is collected in a laboratory cup. The urine sample may identify metabolic problems.
  
  
• Electroencephalogram (EEG). Performed if the child has seizures. During an EEG, activity in the brain is monitored through electrodes that are placed on the scalp. People who have seizures may show abnormally slow frequencies or spikes and other disruptions, even when they are not having a seizure. The physician may request that the EEG be performed both while the child is sleeping and awake in order to give the most accurate picture of normal brain activity.

During the mother’s pregnancy, the treating physician routinely performs a number of diagnostic tests to monitor fetal development. These tests can be early warning signals of risk factors for CP. The tests may include:

• Blood tests on the woman to determine blood Rh factor. This blood test is performed in the first trimester. Different Rh factor between the woman and the fetus increases the risk that her immune system will attack the growing fetus’ red blood cells and cause brain damage. This is readily treatable with immune globulin to prevent the immune system reaction.
  
  
• Amniocentesis. With the aid of an ultrasound guidance, a needle is inserted through the abdomen and into the uterus. Then, a small amount of amniotic fluid (the fluid in the uterus) is removed for testing. This test is generally performed between 16 and 20 weeks into the pregnancy.
  
  
• Chorionic villus sampling (CVS). A sample of the placenta is removed for testing. It may be obtained using either a needle inserted into the abdomen (as in amniocentesis) or via a tube inserted through the vagina. This test can be performed between eight and 12 weeks gestation.
  
  
• Percutaneous umbilical blood sampling (PUBS). A needle is used to remove a sample of blood from the fetus' umbilical cord. This test carries higher risks of complications than amniocentesis or CVS and is typically used only when diagnosis must be made very quickly. It is typically performed later in pregnancy, after 20 weeks gestation.