Hemiplegic cerebral palsy is a specific type of permanent movement disorder that affects muscle control and posture, arising from damage to the developing brain before, during, or shortly after birth. This condition is characterized by motor impairment strictly limited to one side of the body. This form of cerebral palsy is not progressive, meaning the underlying brain injury will not worsen over time.
Defining Hemiplegic Cerebral Palsy
Hemiplegic cerebral palsy, often referred to as spastic hemiplegia, is defined by weakness or paralysis (hemiplegia or hemiparesis) affecting the arm and leg on the same side of the body. This unilateral impairment results from damage to the motor cortex, the region of the brain that controls voluntary movement, typically confined to one of the brain’s hemispheres.
The specific location of the brain damage is directly related to which side of the body is affected due to the principle of contralateral control. If the injury occurs in the right hemisphere of the brain, the motor symptoms will be observed on the left side of the body. Spasticity, characterized by stiff and tight muscles, is the most common motor feature in this type.
Hemiplegic cerebral palsy is one of several classifications of the condition. It is distinct from diplegia, which primarily affects both legs, and quadriplegia, which affects all four limbs. Hemiplegia accounts for a significant portion of all cerebral palsy cases, affecting between 33% and 40% of diagnosed individuals.
Origins and Risk Factors
The underlying cause of hemiplegic cerebral palsy is an injury that occurs in the developing brain. The timing of this injury can be grouped into prenatal (before birth), perinatal (around birth), or postnatal (in early infancy). In many instances, the specific event that caused the damage is never clearly identified.
A stroke, known as a perinatal stroke when occurring around the time of birth, is cited as the most common specific cause. This event involves an interruption of blood flow to the developing brain, leading to localized tissue damage.
Other risk factors include:
- Prenatal factors, such as maternal conditions like infections, preeclampsia, or placental abnormalities.
- Perinatal factors, often relating to complications during labor, such as a lack of oxygen (neonatal asphyxia), prematurity, and low birth weight.
- Postnatal causes, occurring after the immediate newborn period, including severe infections like meningitis, head trauma, or an early childhood stroke.
Physical and Associated Characteristics
The defining motor characteristic of hemiplegic cerebral palsy is the asymmetry of movement, with spasticity and weakness concentrated on one side of the body. The affected arm and hand are often more severely involved than the leg. This often leads to a noticeable hand preference in early infancy, which is an unusual sign in children under 18 months of age.
Spasticity in the leg can result in gait abnormalities, such as toe-walking on the affected side or dragging the foot. Fine motor control is typically reduced in the affected hand, making tasks that require dexterity challenging. Children may exhibit a tendency to keep the affected hand fisted or the elbow bent.
Beyond the motor symptoms, hemiplegic cerebral palsy is often accompanied by a range of associated non-motor characteristics. Seizures or epilepsy are common, occurring in about 60% of children with the condition. Sensory issues can be present, leading to difficulty in perceiving touch, temperature, or the position of the affected limb. Other associated conditions may include visual impairments, difficulties with attention span, and problems with speech.
Confirming the Condition and Intervention Strategies
Diagnosis of hemiplegic cerebral palsy typically begins with clinical observation and a detailed developmental history. Delayed motor milestones, asymmetrical movement, or an early hand preference are considered “red flags” that prompt further evaluation. Specialized tools, such as standardized motor assessments, are used to formally evaluate the child’s movement and posture.
Neuroimaging, specifically Magnetic Resonance Imaging (MRI), is recommended to confirm the presence of a brain abnormality and to determine the location of the injury. In children with hemiplegia, focal infarction is the most frequent abnormality found on imaging. However, the diagnosis itself is clinical, based on the child’s presentation, rather than solely on imaging or laboratory tests.
Intervention strategies are multidisciplinary and focus on maximizing function and mobility. Physical therapy is universally utilized to improve gross motor skills, such as walking and sitting. Occupational therapy is employed to enhance fine motor skills, particularly in the affected hand, and to assist with daily living tasks.
A common specialized technique is Constraint-Induced Movement Therapy (CIMT), which involves restricting the use of the unaffected limb to encourage the child to use the more-affected side. The use of orthotics, such as braces or splints, is also a mainstay of treatment to support limbs and prevent contractures. Medications, such as Botulinum toxin injections, are often used to temporarily reduce spasticity in targeted muscles, which facilitates therapy and improves range of movement.