What is Cerebral Palsy
Cerebral palsy is 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 Characteristics
Cerebral palsy represents the most common physical disability in childhood, affecting approximately 2 to 3 cases per 1000 live births in high-income countries. 4, 2 The condition is fundamentally a clinical diagnosis rather than a single disease entity, encompassing children who share features of a non-progressive brain injury or lesion acquired during the antenatal, perinatal, or early postnatal period. 5
Essential Diagnostic Features
The diagnosis requires the presence of motor dysfunction characterized by:
- Reduced quality of movement 3
- Neurologically abnormal movements 3
- Motor activities substantially below chronological age expectations 3
The brain disturbance itself is non-progressive, though secondary complications can develop over time without appropriate intervention. 1
Clinical Presentation and Motor Types
The motor impairments manifest in distinct patterns:
Spasticity is the predominant form, occurring in 85-91% of cases. 2 Other motor types include:
The anatomical distribution varies:
- Unilateral/hemiplegia: 38% 2
- Bilateral diplegia (lower limbs more affected): 37% 2
- Quadriplegia (all four limbs and trunk): 24% 2
Motor types emerge and evolve during the first 2 years of life, making early classification challenging but not impossible. 1
Associated Conditions and Comorbidities
Cerebral palsy frequently coexists with other neurodevelopmental disorders and medical conditions:
- Chronic pain: 75% 2
- Intellectual disability: 27-49% 4, 2
- Epilepsy: 35-38% 4, 2
- Speech disorders: 33-82% 4
- Hip displacement: 28% 2
- Behavioral disorders: 26% 2
- Sleep disorders: 23% 2
- Visual impairment: 11% 2
- Hearing impairment: 4% 2
- Autism spectrum disorder: 3-9% 4
Etiology and Risk Factors
The underlying cause of cerebral palsy is uncertain in most cases, and birth asphyxia accounts for less than 10% of cases despite historical assumptions. 4
Contributing factors include:
- Genetic variants (14% of cases have a genetic component) 2
- Prematurity and low birth weight 4
- Maternal conditions: thyroid disease, preeclampsia, infections 2
- Intrauterine growth restriction and multiple gestation 2
- Preconception risks: history of stillbirths, miscarriages, low socioeconomic status, assisted reproduction 2
- Infections, trauma, stroke, and hypoxic events in early infancy 2
Recent evidence demonstrates that rare genomic variants contribute significantly to etiology, with exome sequencing revealing pathogenic variants in 31.1% of cases. 4
Neuroimaging Patterns
The most predictive MRI patterns include:
- White matter injury (cystic periventricular leukomalacia or periventricular hemorrhagic infarctions): 56% 2
- Cortical and deep gray matter lesions (basal ganglia, thalamus, watershed injury, multicystic encephalomalacia, stroke): 18% 2
- Brain maldevelopments (lissencephaly, pachygyria, cortical dysplasia, polymicrogyria, schizencephaly): 9% 2
Timing of Diagnosis
Diagnosis can now be made before 6 months' corrected age using standardized assessment tools in combination with clinical history, representing a significant advancement from the traditional diagnosis window of 12-24 months. 1
Before 5 months' corrected age, the most predictive tools are:
- Term-age MRI (86-89% sensitivity) 1
- Prechtl Qualitative Assessment of General Movements (98% sensitivity) 1
- Hammersmith Infant Neurological Examination (90% sensitivity) 1
After 5 months' corrected age:
- MRI (86-89% sensitivity) 1
- Hammersmith Infant Neurological Examination (90% sensitivity) 1
- Developmental Assessment of Young Children (83% C index) 1
Prognosis and Long-Term Outcomes
Two in three individuals with cerebral palsy will walk, three in four will talk, and one in two will have normal intelligence. 2
Mortality risk increases with the number of associated impairments, including intellectual disability, limb function limitations, hearing impairment, and vision impairment. 6 Respiratory diseases and aspiration pneumonia are the leading causes of death, particularly in individuals with swallowing dysfunction. 2
Management Principles
Early diagnosis and prompt referral to diagnostic-specific intervention is essential to optimize infant motor and cognitive plasticity, prevent secondary complications, and enhance caregiver well-being. 2 Early intervention should begin as soon as cerebral palsy is suspected rather than waiting for definitive diagnosis. 2