How to elicit dystonia in a patient with cerebral palsy (CP)?

How to Elicit Dystonia in Cerebral Palsy

To elicit dystonia in a patient with cerebral palsy, focus on observing involuntary shoulder movements during active upper extremity tasks, particularly during hand open/close maneuvers, while distinguishing these from mirror movements. 1

Key Clinical Features to Assess

Upper Extremity Examination

• Perform hand open/close maneuvers as this specific task is most useful for distinguishing between no dystonia and mild dystonia 1
• Observe shoulder movements carefully rather than focusing primarily on the hand, as experts cite shoulder involvement more frequently with increasing dystonia severity 1
• Look for involuntary, repetitive twisting movements and abnormal postures that are characteristic of dystonia 2
• Assess for non-velocity-dependent hypertonia, which distinguishes dystonia from spasticity 2

Critical Distinction: Mirror Movements vs. Dystonia

• Mirror movements are frequently cited when attempting to distinguish between no dystonia and mild dystonia during the hand open/close examination 1
• This differentiation is particularly important as mirror movements can be confused with dystonic movements but represent a different phenomenon 1

Systematic Examination Approach

Movement Observation

• Elicit slow, repetitive involuntary movements by having the patient perform voluntary tasks 3
• Observe for stiff abnormal postures that emerge during or after movement 3
• Note the distribution: dystonia can be unilateral or bilateral 4

Face and Jaw Assessment

• Examine for facial involvement, which occurs in approximately 70% of patients with movement disorders 4
• Look for face twitching, rigidity of facial muscles, and dysarthria related to dystonia of facial or laryngeal muscles 4

Important Clinical Caveats

Diagnostic Challenges

• Dystonia is significantly underdiagnosed in cerebral palsy, especially when coexistent with spasticity—most people with spastic CP have dystonia on dedicated assessment, but only a minority receive a clinical diagnosis 1
• The absence of spasticity and normal tone cannot rule out cerebral palsy, as motor types may emerge and change during the first 2 years of life 5
• Cerebral palsy classically presents with spasticity, dystonia, or athetosis, but may also result in hypotonia 4

Age-Related Considerations

• Motor types and topography may evolve during the first 2 years of life, making early definitive classification challenging 5
• In infants younger than 2 years, motor severity is difficult to accurately predict because almost half have their Gross Motor Function Classification System reclassified 5

Clinical Significance

• Dystonia is an important cause of chronic pain (affecting 75% of CP cases), hospitalization, and musculoskeletal complications 6, 2
• Dystonia interferes with activities and has considerable impact on motor function, pain/comfort, and ease of caregiving 3
• Dystonia requires different treatment approaches than spasticity, making accurate identification clinically essential 2

Red Flags Requiring Prompt Attention

• Loss of motor milestones suggests a neurodegenerative process 4
• Respiratory insufficiency with generalized weakness indicates neuromuscular disorders with high risk of respiratory failure 4
• Abnormalities on brain MRI may require neurosurgical consultation 4