Mixed cerebral palsy is caused by injuries to both the extrapyramidal and pyramidal areas of the brain. Such injuries usually occur while the baby is still developing in the womb. Maternal infections are a common cause of mixed cerebral palsy, as infections within the mother’s body cause inflammation. The inflammation can cause damage the brain of a developing baby. Incompatibility in the mother’s and baby’s blood types can also lead to prenatal complications that can cause mixed cerebral palsy. Damage to the umbilical cord and ruptures in the uterus, as well as encephalitis can cause the condition. Premature infants and multiples (such as twins or triplets) are also at higher risk for developing mixed cerebral palsy.
The most common form of mixed cerebral palsy is spastic/athetoid cerebral palsy. The spasticity is often dominant, while the involuntary athetoid movements become more pronounced and frequent as the child grows. Other combinations are also possible, such as athetoid/ataxic cerebral palsy, though this is less common. Some patients have a combination of ataxic, athetoid and spastic cerebral palsy, though this is extremely rare. It can take years for the symptoms of mixed cerebral palsy to become obvious enough to diagnose.
Mixed cerebral palsy involving athetoid symptoms result from damage to the basal ganglia or the cerebellum because these areas are process the signals that control coordinated movement and posture. Injury to these areas will cause a child to exhibit involuntary movements in the face, arms, and torso. In people with mixed cerebral palsy, the frequency of the involuntary movements interferes with their ability to perform everyday activities like grasping, reaching, eating and speaking. People with mixed cerebral palsy may experience slurred speech, swallowing problems and drooling. Often, symptoms are worse when a person is under emotional stress or excited, and symptoms are less evident when a person is asleep.
As with other forms of cerebral palsy, mixed cerebral palsy is non-progressive; the condition does not worsen with time. However, symptoms may become more pronounced as a person ages. The level of disability depends on the severity of the injuries within the brain. Mixed cerebral palsy is not contagious and cannot be passed on to others, as it is not caused by a virus or bacteria.