Definition of Dystonic Cerebral Palsy in Children
Dystonic cerebral palsy is a subtype of dyskinetic cerebral palsy characterized by involuntary sustained or intermittent muscle contractions that cause twisting and repetitive movements, abnormal postures, or both, resulting from non-progressive disturbances in the developing fetal or infant brain, typically involving lesions to the basal ganglia or thalamus. 1, 2, 3, 4
Core Defining Features
Movement Characteristics:
- Involuntary sustained or intermittent muscle contractions are the hallmark feature 4
- These contractions produce twisting and repetitive movements 4
- Abnormal postures occur either alone or in combination with the abnormal movements 4
- The hypertonia is fluctuating in nature, distinguishing it from the velocity-dependent resistance seen in spasticity 5, 6
Neuroanatomical Basis:
- Dystonic cerebral palsy typically results from non-progressive lesions to the basal ganglia or thalamus 3
- Brain MRI patterns most commonly show cortical and deep gray matter lesions, including basal ganglia or thalamus lesions, watershed injury, multicystic encephalomalacia, or stroke (18% of cerebral palsy cases) 2
Classification Within Cerebral Palsy
Motor Type Classification:
- Dystonia falls under the dyskinetic motor type of cerebral palsy, which affects 4-7% of all cerebral palsy cases 2
- Dystonia is estimated to be present in approximately 15% of children with cerebral palsy, referred to as dyskinetic CP 5
- In dyskinetic cerebral palsy, dystonia and choreoathetosis are typically present together, with dystonia often being more pronounced and severe 3
Clinical Presentation
Distribution Patterns:
- Dystonia can be unilateral or bilateral 7
- Facial involvement occurs in approximately 70% of patients with movement disorders, including face twitching, rigidity of facial muscles, and dysarthria related to dystonia of facial or laryngeal muscles 7
Impact on Function:
- Dystonia interferes with motor function, caregiving activities, and patient comfort 5
- The dystonic component has a major effect on daily activity, quality of life, and societal participation 3
Important Diagnostic Considerations
Coexistence with Other Motor Types:
- Dystonia frequently coexists with spasticity in a subgroup of children with cerebral palsy 5, 6
- 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 7
- Cerebral palsy classically presents with spasticity, dystonia, or athetosis, but may also result in hypotonia 7
Recognition Challenges: