Background
Cerebral palsy (CP) is a prevalent group of motor disorders that affects an individual’s ability to maintain balance, posture, and mobility. It is caused by abnormal brain development or brain damage that affects a person’s ability to control muscles, stemming from dysfunction in the central nervous system and the skeletomuscular system. These three types of CP are classified by physicians depending on which areas of the brain are affected. Spastic cerebral palsy is the most common, affecting 80%, resulting in increased muscle tone making them unnaturally stiff and awkward to move. Dyskinetic cerebral palsy results in changing muscle tone that creates issues with controlling limbs and mobility, with uncontrollable or jerky movements, as well as potentially affecting the ability to talk or swallow. Ataxic CP occurs when there are issues with balance and coordination in movement, making it difficult to execute highly controlled movements. Patients can have a mixture of more than one type of CP (CDC, 2019).
CP arises primarily in young children, with symptoms seen as early as birth. Signs of CP can vary greatly due to the range of the disorder but becomes prevalent when children have a delay in reaching motor or movement milestones in development. Screening for the condition is done through developmental monitoring (surveillance) which tracks growth and development over time, followed by medical evaluations. The prevalence of CP in population-based studies suggests the condition is seen anywhere from 1.5 to 4 per 1,000 live births. The rate of CP in the U.S. is approximately 1.75 per 1,000 live births. There are minor racial disparities for the disease with 2.34/1000 in non-Hispanic Blacks and 1.34/100 in the non-Hispanic White population (Stavsky et al., 2017).
Normal Anatomy
The central nervous system (CNS) consists of the brain and the spinal cord. The brain is divided into four major regions of the cerebrum, diencephalon, cerebellum, and the brain stem which is connected to the single structure of the spinal cord. The central nervous system is connected to the peripheral nervous system, which consists of sensory and motor divisions. The sensory part carries signals from the body to the CNS to be decoded, while the motor division carries the signals from the CNS, resulting in body response to stimuli and sensory information. The basal nuclei in the cerebrum of the brain are connected with nuclei in the brain stem, forming a functional group that becomes a motor pathway. The frontal lobe of the brain is primarily associated with motor function. The precentral gyrus of the frontal lobe the primary motor cortex, instruct cells in the spinal cord to move skeletal muscles. If a command is sent down from the primary motor cortex of the frontal lobe, a copy of the instruction is sent to the cerebellum. Sensory feedback is then sent from the muscles and joints regarding proprioceptive information and sensations of balance and movement. The cerebellum then sends a corrective command based on the original cortical command and the received sensory information. The signal is output into the midbrain, descending into the spinal cord to control proper motor function of skeletal muscles (“Anatomy and physiology”).
Physiology of the Disease
Different types of CP affect various areas of the brain. Spastic CP impacts the cerebral cortex and corticospinal tracts. Lesions on the corticospinal tract created uncontrolled facilitatory input of the spinal reflex arc, leading to hyperactivity of stretch reflexes that cause spasticity. Dyskinetic CP impacts the basal ganglia of the brain, a primary component of the extrapyramidal system. Neonatal hyperbilirubinemia results in neurotoxic action of the unconjugated bilirubin on the basal ganglia. It helps to control automatic movements as well as postural or precise movements. Lesions on the basal ganglia cause abnormal involuntary movements including athetosis and dystonia. For ataxic CP, lesions on the cerebellum result in ataxia that leads to balance and proprioception issues (Norton, 2014). All CP disorders are caused to areas of the brain which directly affect the nervous system function. Virtually all nervous system functions are affected by one or several CP disorders including movement, learning, vision, hearing, learning, and cognitive processes and development.
Treatment and Prevention
Treatment of CP is dependent on individual patient factors, particularly affected body parts and severity of symptoms. There is currently no cure that can reverse initial damage to the brain, and the person will likely have dysfunctions for the rest of their life. The most common treatment is the use of physical therapy, starting from a young age, meant to continually improve muscular and skeletal strength and independent motor functioning. As the condition evolves or the patient grows up, physical therapy changes to accommodate those needs and can significantly improve quality of life by relieving pain, increasing self-independence, and improving the range of motion while mitigating dangerous symptoms such as contracture. Another treatment commonly implemented with physical therapy is the use of orthotics by introducing assistive devices (casts, splints, braces) that can compensate for the weak musculoskeletal system (Novak et al., 2017).
Medication is used in cerebral palsy to treat immediate symptoms such as antispasmodic drugs to address affected muscle groups as well as medications to treat co-occurring symptoms such as pain management or learning issues. Surgical intervention (orthopedic surgery or neurosurgery) is possible on a case-by-case basis to improve mobility and reduce limitations caused by muscle tightness (Pons et al., 2016). It is unknown how to prevent the disease since its specific cause has not been found, with only suggestions that it may be a genetic or early development issue resulting in abnormal brain development in the womb or early childhood. The Health and lifestyle of mothers is the only precaution that can be taken to prevent CP by avoiding any potential inflammation, injury, or asphyxiation of the brain of the fetus, ensuring a healthy pregnancy (Stavsky et al., 2017).
References
Anatomy and physiology. (2013). OpenStax.
CDC. (2019). Cerebral Palsy (CP).
Norton, N. S. (2014). Cerebral Palsy. In Reference Module in Biomedical Sciences (pp. 1-3). Elsevier.
Novak, I., Morgan, C., Adde, L., Blackman, J., Boyd, R. N., Brunstrom-Hernandez, J., Cioni, G., Damiano, D., Darrah, J., Eliasson, A.-C., de Vries, L. S., Einspieler, C., Fahey, M., Fehlings, D., Ferriero, D. M., Fetters, L., Fiori, S., Forssberg, H., Gordon, A. M., … Badawi, N. (2017). Early, accurate diagnosis and early intervention in Cerebral Palsy. JAMA Pediatrics, 171(9), 897.
Pons, C., Brochard, S., Gallien, P., Nicolas, B., Duruflé, A., Roquet, M., Rémy-Néris, O., & Garlantezec, R. (2016). Medication, rehabilitation and health care consumption in adults with cerebral palsy: a population based study. Clinical Rehabilitation, 31(7), 957–965.
Stavsky, M., Mor, O., Mastrolia, S. A., Greenbaum, S., Than, N. G., & Erez, O. (2017). Cerebral Palsy-Trends in epidemiology and recent development in prenatal mechanisms of disease, treatment, and prevention. Frontiers in Pediatrics, 5, 21.