Spastic Cerebral Palsy
Spastic CP is the most common type, affecting approximately 70–80% of people with cerebral palsy. It is caused by damage to the motor cortex or the white matter pathways that carry movement signals from the brain.
The hallmark of spastic CP is increased muscle tone (hypertonia). Muscles feel stiff, tight, and resist stretching. This can make movements slow, effortful, and less coordinated.
Common features include:
- Stiff, tight muscles that are difficult to move
- Scissoring of the legs (legs crossing over each other when walking)
- Toe walking due to tight calf muscles
- Joint contractures (permanent shortening of muscles and tendons)
- Difficulty with fine motor tasks like writing, buttoning, or using cutlery
Dyskinetic Cerebral Palsy
Dyskinetic CP (also called athetoid or dystonic CP) is caused by damage to the basal ganglia — the deep brain structures that help regulate and smooth out movement. It affects about 6% of people with CP.
The main feature is involuntary, uncontrolled movements that can be slow and writhing (athetosis) or sustained and twisting (dystonia). These movements often increase during stress or effort and may decrease during sleep.
Common features include:
- Fluctuating muscle tone — sometimes too stiff, sometimes too floppy
- Involuntary movements of the face, tongue, arms, and legs
- Difficulty controlling the mouth and tongue, affecting speech and eating
- Difficulty sitting still or maintaining a posture
- Movements that are unpredictable and difficult to control
People with dyskinetic CP often have normal or near-normal intelligence, but their involuntary movements can make it very difficult to communicate and perform daily tasks without assistance.
Ataxic Cerebral Palsy
Ataxic CP is the least common type, affecting about 6% of people with CP. It is caused by damage to the cerebellum, which coordinates balance, coordination, and precise movements.
Common features include:
- Shaky or trembling movements, especially during fine motor tasks
- Difficulty with balance and depth perception
- Unsteady, wide-based walking (ataxic gait)
- Difficulty with precise movements like reaching for objects
- Challenges with rapid or alternating movements
Mixed Cerebral Palsy
Many people with CP have features of more than one type. This is called mixed CP. The most common combination is spastic-dyskinetic, where a person has both stiff muscles and involuntary movements. Mixed CP occurs when damage affects multiple areas of the brain.
Body Distribution (Topography)
CP is also classified by which parts of the body are affected:
- Hemiplegia/hemiparesis — one side of the body (e.g., left arm and left leg). Most common in spastic CP.
- Diplegia/diparesis — mainly the legs, with arms less affected. People with diplegia often walk but may use aids.
- Quadriplegia/quadriparesis — all four limbs, trunk, and often the face and mouth. This is usually the most severe form.
- Monoplegia — one limb only (rare)
- Triplegia — three limbs (uncommon)
Summary
The type and distribution of CP depend on where in the brain the injury occurred. Understanding the type helps guide treatment and support, but every person is unique regardless of their classification.