How is Cerebral Palsy Diagnosed

Doctors diagnose cerebral palsy by testing an infant's motor skills and looking carefully at the mother’s and infant's medical history. In addition to checking for those symptoms described above -- slow development, abnormal muscle tone, and unusual posture -- a physician also tests the infant's reflexes and looks for early development of hand preference.

Reflexes are movements that the body makes automatically in response to a specific cue. For example, if a newborn baby is held on its back and tilted so the legs are above its head, the baby will automatically extend its arms in a gesture, called the Moro reflex, that looks like an embrace. Babies normally lose this reflex after they reach 6 months, but those with cerebral palsy may retain it for abnormally long periods. This is just one of several reflexes that a physician can check.

Doctors can also look for hand preference—a tendency to use either the right or left hand more often. When the doctor holds an object in front and to the side of the infant, an infant with hand preference will use the favored hand to reach for the object, even when it is held closer to the opposite hand. During the first 12 months of life, babies do not usually show hand preference. But infants with spastic hemiplegia, in particular, may develop a preference much earlier, since the hand on the unaffected side of their body is stronger and more useful.


The next step in diagnosing cerebral palsy is to rule out other disorders that can cause movement problems. Most important, doctors must determine that the child's condition is not getting worse. Although its symptoms may change over time, cerebral palsy by definition is not progressive. If a child is continuously losing additional motor skills, the problem more likely springs from elsewhere—including genetic diseases, muscle diseases, disorders of metabolism, or tumors in the nervous system. The child's medical history, special diagnostic tests, and, in some cases, repeated check-ups can help confirm that other disorders are not at fault.