What is the definition of cerebral palsy in children?

Definition of Cerebral Palsy in Children

Cerebral palsy is defined as "a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain." 1, 2, 3

Core Diagnostic Criteria

The definition emphasizes three essential components that must be present:

• Permanent motor disorders: The movement and posture abnormalities are lifelong, though the clinical manifestations may evolve during the first 2 years of life as the child's motor repertoire develops 1

• Activity limitation: The motor impairments cause functional restrictions in the child's ability to perform age-appropriate activities 1, 2

• Non-progressive brain disturbance: The underlying brain injury or lesion occurred during fetal or infant brain development and does not worsen over time, distinguishing it from neurodegenerative conditions 1, 3

Clinical Characteristics

Cerebral palsy is a clinical diagnosis, not a single disease entity, but rather a descriptive term for children who share features of early brain injury with varying presentations 1, 4

Timing of Brain Injury

The causative brain disturbance must have occurred during one of three developmental periods:

• Prenatal (fetal) period: During pregnancy, including genetic factors (14% of cases), maternal infections, thyroid disease, preeclampsia, or intrauterine growth restriction 3

• Perinatal period: During labor and delivery, though birth asphyxia accounts for less than 10% of cases 1

• Early postnatal period: During infancy, from infections, trauma, stroke, or hypoxic events 3

Motor Type Classification

The disorder manifests in four primary motor patterns, though these may emerge and change during the first 2 years:

• Spasticity (85-91% of cases): Increased muscle tone with velocity-dependent resistance to passive movement 1, 2, 3

• Dyskinesia (4-7%): Including dystonia and athetosis 1, 3

• Ataxia (4-6%): Impaired coordination and balance 1, 3

• Hypotonia (2%): Decreased muscle tone, though not classified in all countries 1, 3

Topographical Distribution

Spasticity is further categorized by body region affected:

• Unilateral (hemiplegia): 38% of cases, affecting one side of the body 1, 3

• Bilateral diplegia: 37% of cases, with lower limbs affected more than upper limbs 1, 2, 3

• Quadriplegia: 24% of cases, affecting all four limbs and trunk 1, 3

Epidemiology and Prevalence

• Most common physical disability in childhood, with a prevalence of 2.1 per 1000 live births in high-income countries 1, 3, 5

• Prevalence is 70 times higher in children born weighing less than 1500g compared to those over 2500g 5

Associated Comorbidities

The definition acknowledges that motor disorders often coexist with other impairments, though these are not required for diagnosis:

• Intellectual disability affects 49% of cases 1, 2, 3
• Epilepsy affects 35-38% of cases 1, 2, 3
• Speech disorders affect 33-82% of cases 1
• Chronic pain affects 75% of cases 1, 2, 3
• Musculoskeletal problems affect 28% of cases 1, 2, 3

Critical Diagnostic Distinctions

The "non-progressive" criterion is essential for excluding other conditions:

• Loss of previously acquired motor milestones suggests a neurodegenerative process, not cerebral palsy 3

• The brain lesion itself does not worsen, though secondary complications (contractures, hip displacement, scoliosis) may develop over time 4

• Clinical signs and symptoms emerge and evolve before age 2 years as the child's voluntary motor repertoire expands 1

Functional Prognosis

Despite the permanent nature of the disorder, functional outcomes vary widely:

• 2 in 3 individuals will walk 1, 2, 3
• 3 in 4 will talk 1, 2, 3
• 1 in 2 will have normal intelligence 1, 2, 3