Cerebral palsy is a nondegenerative neurological disorder that affects motor skills and movement. Complications during childbirth were thought to be the cause of the disorder in the 1800s, but 20th-century research found that cerebral palsy is rooted in abnormal development of the fetal brain, presumably caused by genetic mutations, maternal infections or fetal injury. Cases of acquired cerebral palsy can be traced to specific instances of brain damage early in life. Advances in clinical imaging, such as magnetic resonance imaging, have identified specific brain areas associated with the disorder. As expected, the brain regions directly involved in cerebral palsy are the motor areas, and the disorder is caused by an interruption of the signals between the body and brain.
Cerebellum
The cerebellum, the major portion of the brain stem, integrates signals to achieve balance and coordination. Damage to this region of the brain results in ataxia. Ataxic cerebral palsy is the least common form of the disorder. Individuals with a lesion in the cerebellum have trouble with balance and depth perception, poor muscle tone, difficulties walking, speech difficulties, uncoordinated grasping and reaching, and unsteady hands.
Basal Ganglia
The red nucleus and substantia nigra are motor structures in the midbrain, the upper portion of the brain stem that connects the cerebellum and cortex. Along the midbrain, the basal ganglia include the caudate nucleus, putamen and globus pallidus. Damage to these structures results in jerky, involuntary movements. This type of cerebral palsy is referred to as athetoid, or choreo-athetoid, and can also accompany speech difficulties. Athetosis is the presence of the movements in the hands and face. Chorea is the presence of the movements in the head, arms or legs. Dystonia is the presence of the movements in the trunk.
Motor Cortex
The motor cortex is found in the frontal cortex, the top and front portion of the brain. Damage to the motor areas of the brain results in spastic muscles, which are stiff and limited in movement. Spastic cerebral palsy is the most common form of the disorder. The muscles in the affected area of the body do not move in a paired, coordinated fashion, but co-contract in a manner that blocks effective movement. The severity and affected area has a broad range, from mild and limited to whole body, and can change over time.
Affected individuals often have "mixed-type" cerebral palsy and individual manifestations of the condition depending on the extent and exact location of the brain damage.
References
- National Institute of Neurological Disorders and Stroke: Cerebral Palsy
- The Ontario Foundation for Cerebral Palsy: About Cerebral Palsy
- The Ontario Foundation for Cerebral Palsy: A Guide to Cerebral Palsy
- Serendip: Brain Structures and Their Functions
- University of Idaho: Medical Science 532 Neuroscience Course
