Cerebral palsy is not a specific disease but a clinical syndrome caused by a non-progressive injury to the developing brain that results in a disorder of movement and posture that is permanent but not unchanging. It is the most common cause of physical disability affecting children in developed countries. The incidence is steady in most countries at approximately 2 per 1000 live births. The prevalence of cerebral palsy is much higher in children with birth weight under 1500 g and in those born earlier than 28 weeks of gestation. The location, timing and severity of the brain lesion are extremely variable, which results in many different clinical presentations. Despite the static nature of the brain injury, the majority of children with cerebral palsy develop progressive musculoskeletal problems such as posturing and muscle contractures (Koman et al., 2004). Additionally, as pointed out in an expert consensus on cerebral palsy, it is important to recognize that there are also frequent yet inconsistent disturbances of sensation, cognition, communication and perception; abnormalities of behavior; and seizures (Bax et al., 2005).
Cerebral palsy may be classified according to the cause of the brain lesion (when this is known), and the location of the brain lesion as noted on imaging such as MRI or CT. Clinically more useful classification schemes are based on the type of movement disorder, the distribution of the movement disorder (Box 15.1) and the gross motor function of the child.