What are the diagnostic criteria for cerebral palsy in a pediatric patient?

Diagnostic Criteria for Cerebral Palsy

Cerebral palsy is a clinical diagnosis requiring motor dysfunction as the essential criterion, plus at least one additional criterion: either abnormal neuroimaging or clinical history indicating risk for cerebral palsy. 1

Core Definition

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

Essential Criterion (Mandatory)

Motor dysfunction must be present, characterized by: 1

• Reduced quality of movement (e.g., absent fidgety general movements on Prechtl assessment) 1
• Neurologically abnormal movements (e.g., early observable hand asymmetry or suboptimal Hammersmith Infant Neurological Examination scores) 1
• Motor activities substantially below chronological age expectations (e.g., head lag, not sitting, inability to grasp, or not reaching for toys when age-appropriate) 1

Critical Caveat for Motor Assessment

In milder presentations, particularly unilateral cerebral palsy, infants may score within normal range on standardized motor assessments while still displaying abnormal movements. 1 For example:

• An infant with hemiplegia might obtain normal fine-motor scores but complete assessment one-handed 1
• An infant with diplegia may achieve normal upper limb scores and abnormal lower limb scores, producing a combined total motor score within normal range 1

Therefore, assessments must be performed by professionals skilled at distinguishing atypical movement from typical variation. 1

Additional Criteria (At Least One Required)

1. Abnormal Neuroimaging

MRI with or without serial cranial ultrasound in preterm infants identifies neuroanatomical abnormalities predictive of cerebral palsy. 1 The most predictive patterns include: 1

• White matter injury (56%): cystic periventricular leukomalacia or periventricular hemorrhagic infarctions 1
• Cortical and deep gray matter lesions (18%): basal ganglia or thalamus lesions, watershed injury (para-sagittal injury), multicystic encephalomalacia, or stroke 1
• Brain maldevelopments (9%): lissencephaly, pachygyria, cortical dysplasia, polymicrogyria, or schizencephaly 1

2. Clinical History Indicating Risk for Cerebral Palsy

Preconception risks: history of stillbirths, miscarriages, low socioeconomic status, assisted reproduction, abnormal genetic copy number variations 1

Pregnancy risks: genetics, birth defects, multiples, males, maternal thyroid disease or preeclampsia, infection, intrauterine growth restriction, prematurity, substance abuse 1

Age-Specific Diagnostic Pathways

Before 5 Months Corrected Age (Newborn-Detectable Risks)

Half of all infants with cerebral palsy have high-risk indicators identifiable in the newborn period. 1 Most predictive tools: 1, 2

• Term-age MRI (86-89% sensitivity) 1, 2
• Prechtl Qualitative Assessment of General Movements (98% sensitivity; 95-98% when fidgety movements absent at 3-5 months) 1, 2
• Hammersmith Infant Neurological Examination (90% sensitivity; 96% predictive value when score <57 at 3 months) 1, 2

After 5 Months Corrected Age (Infant-Detectable Risks)

The other half of infants with cerebral palsy have uneventful pregnancy/labor, with parents or professionals first noticing delayed motor milestones (e.g., not sitting at 9 months or hand asymmetry). 1 Most predictive tools: 1

• MRI (86-89% sensitivity, where safe and feasible) 1
• Hammersmith Infant Neurological Examination (90% sensitivity) 1
• Developmental Assessment of Young Children (83% C index) 1

Timing of Diagnosis

Diagnosis typically occurs between 12 and 24 months of age, though early diagnosis is recommended before 6 months corrected age when possible using standardized assessments. 1, 2

Motor Type Classification

Four motor types exist but may emerge and change during the first 2 years: 1

• Spasticity (85-91%): categorized topographically as unilateral/hemiplegia (38%) or bilateral including diplegia (37%) and quadriplegia (24%) 1
• Dyskinesia (4-7%): including dystonia and athetosis 1
• Ataxia (4-6%) 1
• Hypotonia (2%): not classified in all countries 1

Common Pitfalls to Avoid

Do not delay diagnosis waiting for spasticity to develop, as motor types evolve and some children have dyskinetic or ataxic forms without spasticity. 3

Do not assume normal standardized motor scores exclude cerebral palsy in milder presentations—observe for asymmetries and abnormal movement quality. 1

Do not diagnose cerebral palsy based on history alone—congruent abnormal findings on neuroimaging, standardized neurological assessments, and standardized motor assessments are required. 1