A good, authoritative definition of "cerebral palsy" is that provided by the United States Centers for Disease Control (CDC), which defines this debilitating illness as follows:
"CP is caused by abnormal brain development or damage to the developing brain that affects a person’s ability to control his or her muscles."
That is a very brief, concise definition of cerebral palsy, but it is not the whole story of this particular disease, but is far from complete for the purposes of discussion. Cerebral palsy generally affects babies before or immediately after birth. The causes of cerebral palsy can be numerous, but the following from a cerebral palsy research and family support organization, a link to which is provided below, summarizes this aspect of the discussion well:
"The cause of cerebral palsy is a brain injury or brain malformation that occurs while the brain is developing — before, during, or after birth. As a result of the brain damage during brain development a child’s muscle control, muscle coordination, muscle tone, reflex, posture and balance can be affected. It can also impact a child’s fine motor skills, gross motor skills, and oral motor functioning."
Cerebral palsy can manifest itself in several main ways, including uncontrollable muscle spasms, difficulties maintaining equilibrium (e.g., balance), and stiff muscles. According to the National Institutes of Health, early signs of this disease are often detectable within the first three years of a child's life. While there is no cure for cerebral palsy -- and, it is important to keep in mind that levels of severity differ widely among those affected by this disease -- there are treatment regimens that do help most sufferers to function better than they otherwise would, including physical and occupational therapy, medications to relax stiff muscles or control spasms, surgical procedures to correct abnormalities, and the use of specially-tailored information technologies to enable rudimentary (or better) communications. [See the link to the U.S. National Institutes of Health provided below]
In conclusion, the most common symptoms of cerebral palsy, as noted, are stiff muscles, uncontrollable muscle spasms and general difficulty controlling one's upper and lower extremities, and difficulty communicating orally owing to the impaired brain functioning that is the cause of cerebral palsy. Most often this impaired brain function occurs before birth, but can occur during or soon after birth, with indications visible within three years of birth.