A condition that affects about three quarter of a million Americans, cerebral palsy was first described in the 1840s by William Little. It is a common developmental disability, which causes problems with movement and posture. Cerebral Palsy (CP) is defined as “an umbrella term covering a group of non-progressive, but often changing, motor impairment syndromes secondary to lesions or anomalies of the brain arising in the early stages of its development” (Pirila et al., 2007, p.116). It poses significant diagnostic and therapeutic difficulties for the physician and considerable hardships to patients and their families (Sankar & Mundkur, 2005). This paper describes the anatomy and physiology of the brain, where the discussed condition originates. It also examines the etiology and risk factors, pathophysiology, signs and symptoms, diagnostic techniques, various treatment procedures and prognosis of the condition.
Brain: Anatomy and Physiology
Brain is the central element of the nervous system, which is responsible for organizing and processing capabilities in humans. It is the center of consciousness, coordination, memory and sensation. The brain receives and processes sensory inputs from various organs and generates appropriate responses. It consists of three major structures – the cerebrum, the cerebellum, and the brain stem. The cerebrum is the largest section of the brain and comprises two hemispheres; these hemispheres are connected with the help of nerve fibers, usually called “corpus callosum”. Each brain hemisphere is related to and responsible for the contralateral body side. The surface of cerebral hemispheres consists of ridges, or gyri, which separated by grooves, also known as “sulci and fissures” (Alcamo & Krumhardt, 2004).
The fissures divide the cerebral hemisphere into the four lobes – parietal lobe, frontal lobe, temporal lobe, and occipital lobe. The outer layer of cerebrum is called the “cerebral cortex” and is made up of grey matter. Each cerebral hemisphere encloses a cavity known as “ventricle”, which contains cerebrospinal fluid. Cerebrum is the center of all sensory and motor activities. It receives and interprets sensory impulses and generates responses to these stimuli. The temporal lobe is responsible for hearing. The parietal lobe is responsible for understanding and speech, and the occipital lobe is responsible for vision. The frontal lobe is the primary motor area, which is also associated with speech, reasoning, thinking, logic and creativity (Alcamo & Krumhardt, 2004). The cerebellum lies under the cerebral hemispheres and consists of two hemispheres, which communicate with other parts of the brain by means of nerve tracts known as cerebellar peduncles. The surface of cerebellum is convoluted and marked by parallel ridges and grooves. Cerebellum controls the skeletal muscle activity, maintains posture, balance and coordinates movement (Alcamo & Krumhardt, 2004).
The third element of the brain, the brain stem, comprises a number of structures, including the diencephalon, the midbrain, the pons, and the medulla oblongata. The diencephalon lies between the cerebral hemispheres and encloses the third ventricle. It contains masses of grey matter called the nuclei. One of the nuclei, known as the thalamus, passes the impulses of pain and temperature along to the cerebral cortex. Another nucleus, the hypothalamus, produces hormones, which regulate many bodily functions. The hypothalamus also controls hunger, water balance, body weight, and body temperature. The midbrain lies between the diencephalon and the pons, and its nerve fibers connect the cerebrum to the spinal cord. The pons lies between the midbrain and the medulla oblongata and relays impulses from the medulla to the cerebrum and back. The medulla is the last element of the brain stem and encloses the fourth ventricle. All ascending and descending nerve tracts pass through it. The medulla controls numerous activities, such as heartbeat, breathing, and contraction of smooth muscles, as well as sneezing, coughing, vomiting, and swallowing (Alcamo & Krumhardt, 2004).
Etiology and Risk Factors
The etiology of CP is vast and varied. Its causes may be congenital, infectious, inflammatory, genetic, traumatic or metabolic. The developing brain may be injured at the prenatal, perinatal or postnatal stage. Statistically, almost 75% – 80% of all CP cases occur as a result of prenatal injury, and less than 10% are due to asphyxia or major birth trauma (Miller, 2005). Among the most important prenatal causes of CP are congenital malformations of the brain and blood vessels, vascular occlusion, intrauterine viral infections, toxins, and metabolic disorders. Perinatal causes include significant asphyxia at birth, intracranial hemorrhage, infections, untreated jaundice, hypoglycemia and seizures. Postnatal causes of CP range from severe infections and injuries like malaria, septicemia, meningitis, encephalitis, and near drowning incidents to brain injury during accidents. CP generally develops due to a combination of unfavorable events, which cause motor damage. A large number of risk factors are associated with the disease. They may occur before or during pregnancy, during labor and delivery, or shortly after birth (Miller, 2005).
Before pregnancy, the late onset of or irregular menstruation, as well as long monthly cycles in women, present a serious risk factor for CP. Other maternal risk factors include epilepsy, hyperthyroidism, and severe hypertension. During pregnancy, the main risk factors for CP are premature delivery, multiple pregnancy, pre-eclampsia, and trauma during pregnancy. During labor and delivery, prolapsed cord, severe intrapartum bleeding, and traumatic delivery can cause asphyxia in the neonate, leading to brain damage. Low birth weight also increases the risks of cerebral palsy. In newborns, seizures, sepsis, and respiratory diseases greatly increase the risks for developing CP (Miller, 2005).
Neuromuscular Control in Cerebral Palsy
Cerebral palsy affects motor control. CP decreases the muscle tone and results in the abnormal motor reflex function. Consequently, the stability and mobility of joints is impaired. A healthy brain controls the muscle tone of the body in response to sensory stimuli, but in people with cerebral palsy, the motor control center of the brain is damaged. As a result, physical movements become limited, accompanied by impairments in the hearing, vision and mental functions. Musculoskeletal disorders develop due to the underlying condition (Miller, 2005).
Neurophysiologically, cerebral palsy is classified into three major types: Spastic, Athetoid/ Dyskinetic, and Ataxic. Spastic is the most common type of CP and occurs due to the damage in the upper motor neurons, which transmit impulses from the central nervous system to muscles to control posture, reflexes, and muscle tone. Muscles become hypertonic, and increased muscle tension prevents stretching. Athetoid cerebral palsy results from the problems in the basal ganglia. This form of CP manifests through slow and writhing movements, which are involuntary and uncontrolled. Ataxia is caused by the damage to the cerebellum and its pathways, leading to unsteadiness and difficulties maintaining balance (Miller, 2005).
Signs and Symptoms
The early signs and symptoms seen in all types of cerebral palsy include muscle tone impairments, problems with posture and reflexes, delayed motor development, and abnormal motor performance. The severity of symptoms and disability varies from individual to individual. Accordingly, individuals with CP may face anything, from slight clumsiness in movements to complete immobility. Though severe damage may be apparent at birth, the symptoms of CP generally appear between two and four years of age, as children’s growth and development do not proceed normally (Sankar & Mundkur, 2005). In spastic cerebral palsy, symptoms may include hemiplegia, diplegia or quadriplegia, depending upon the area affected. In spastic hemiplegia, one side of the body, including head, neck and trunk, is affected, and the arm is usually affected more than the leg. In diplegia, both lower limbs are affected. In quadriplegia, all four limbs are severely affected. About 60% patients with CP are mentally retarded (Sankar & Mundkur, 2005).
Associated disorders include visual and hearing impairments, epilepsy, speech and language disorders, and oromotor dysfunctions, such as drooling and difficulties with eating and swallowing. Difficulties with feeding can further result in malnutrition, affecting children’s physical growth. Many children with cerebral palsy also display a host of psychiatric and behavioral problems, which include anxiety, depression, learning disabilities, attention deficit disorder, and sensory integration disorder (Sankar & Mundkur, 2005).
Diagnosis is done mainly by history and physical examination of the patient. With the exception of very severe cases, cerebral palsy can be diagnosed only in infants older than 6 months. Clinical observation reveals delayed developmental milestones, abnormal muscle tone, preference of using one hand over the other, delayed emergence of protective reflexes, persistent infantile reflexes, prominent fisting, asymmetrical movements during crawling, and hyperreflexia. In milder cases, the child may need to be observed over time, before the diagnosis is confirmed. Definitive diagnosis is usually made by the age of 18 months (Sankar & Mundkur, 2005).
X-rays and blood tests are performed to rule out other similar conditions, such as degenerative neuromuscular diseases, nervous system tumors, genetic and muscle diseases, and metabolic disorders. MRI, CT scan or cranial ultrasound is done to establish the etiology of the disease. Family history of epilepsy also requires that an EEG be obtained. Other associated disorders are diagnosed with the help of intelligence tests, an ophthalmological and otological examination, psychiatric evaluation, and examination by a speech and language pathologist and an educationist (Mangal, 2007). To confirm the diagnosis, medical professionals need to identify brain impairments/abnormalities and ensure that the condition does not worsen. The final diagnosis should wait, until the process of brain development is complete (Mangal, 2007).
Treatment methods for cerebral palsy include physical therapy, occupational therapy, and speech therapy to develop individuals’ motor skills and overall health. Physical therapy helps children to develop strength, balance, coordination, and functional mobility. It also teaches children and their families to select and use adaptive equipment. Occupational therapy is focused on developing individuals’ fine motor skills, improving the upper body function, and enhancing posture. With occupational therapy, the child learns to cope with the basic activities, such as eating, swallowing, dressing, using toilet, etc. Speech therapy helps to overcome communication problems, teaching the child to understand and express him(her)self (Mangal, 2007).
In addition to the therapeutic treatment methods, a number of aids for vision and hearing, as well as braces and splints to correct muscle deformities, are recommended. A variety of assistive technology options are available to make the child independent and mobile. These include walkers, wheelchairs, powered scooters, positioning devices, adapted eating equipment, bath chairs, speech, vision and hearing aids, etc. (Mangal, 2007). Other treatment options include oral medications to relax the hypertonic muscles, ease seizures, and reduce abnormal movements. Selective dorsal rhizotomy and orthopedic surgery can be used to correct bone deformities. Proper treatment at an early age usually results in a markedly improved quality of life for patients of cerebral palsy (Mangal, 2007).
CP is incurable but preventable. Preventive measures include taking care to reduce or eliminate the risk factors of CP in the pre-natal, delivery and post-natal stages. Prenatal tests can alert a woman to possible risk factors. Pregnant women should be tested for the Rh factor. Newborn jaundice should be treated promptly with phytotherapy. Pregnant women should not be exposed to infections, X-rays, drugs and medications. Effective control of anemia, thyroid disorders, diabetes and nutritional deficiencies, good pre-natal care, and protection of infants from injury or accidents can zero the risks of CP (Cerebral Palsy Source, n.d.)
Cerebral Palsy is a non-progressive condition, since, with time, the brain damage neither improves nor worsens. However, symptoms can change over years. CP results in lifelong disability but, with proper rehabilitative therapy, marked improvements in the quality of life are quite possible. The prognosis depends upon the type of cerebral palsy, the extent of damage to the brain, and the child’s physical and mental abilities. Early diagnosis and effective management of the condition are essential. A multi-disciplinary approach involving a pediatrician, orthopedic surgeon, and neurologist, with the elements of physiotherapy, occupational therapy, and speech therapy will significantly improve the prognosis (Cerebral Palsy, n.d.).Except for severe cases where an individual is totally dependent on others,, a person with CP may live a completely independent or semi-independent life, have near-normal life expectancy, and even have and rear children (Cerebral Palsy, n.d.).
Cerebral Palsy is a disorder, which is irreversible and non-treatable but preventable. People need to be aware of the condition and its risks, especially those in the reproductive age group, to know the causes and effects of cerebral palsy. Young people and expectant mothers should also be educated about the factors, which put the child at risk of brain injury. Awareness of the causes and risk factors for CP allow expectant parents to exercise greater caution in the prenatal, perinatal and neonatal stages. The causes and risk factors of cerebral palsy are currently under research. More information about the role of infection, inflammation, and coagulation in the perinatal period can be obtained with the help of sophisticated brain imaging techniques. Ongoing research is likely to improve the public understanding of the disorder and contribute to the development of effective preventive strategies.