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 INTRODUCTION

The term cerebral palsy (CP) was originally coined more than a century ago and loosely translates as "brain paralysis." However, a precise definition has remained elusive because cerebral palsy is not a single diagnosis but an "umbrella" term describing non-progressive brain lesions involving motor or postural abnormalities that are noted during early development, Mutch (2011). This has led to many definitions fro different authors but pointing to the same facts. For instance, Bax (2005) defined Cerebral palsy as "A group of disorders of the development of movement and posture causing activity limitations that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of cerebral palsy are often accompanied by disturbances of sensation, cognition, communication, perception, and/or behavior and/or a seizure disorder." While it has also been defined as an umbrella term encompassing a group of a non-progressive and non contagious motor conditions that cause physical disability in human development, chiefly in the various areas of body movement, NCBDDD, (2002)

Since it leads to a non progressive injury to the brain it impact on the functioning of the body is vast. Cerebral palsy has many types which are dependant on the area of the brain that has been injured and the final presentation of the condition.

As any other condition, management of Cerebral palsy involves a multi-displinary approach of the health care team. The prognosis is also dependant on the individual.

ANATOMY OF THE BRAIN

The human brain is the center of the human nervous system. Enclosed in the cranium, the human brain has the same general structure as that of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size.

Most of the spatial expansion comes from the cerebral cortex, a convoluted layer of neural tissue which covers the surface of the forebrain. Especially expanded are the frontal lobes, which are associated with executive functions. The brain controls the other organ systems of the body, either by activating muscles or by causing secretion of chemicals such as hormones and neurotransmitters. This centralized control allows rapid and coordinated responses to changes in the environment. Some basic types of responsiveness are possible without a brain.

The brain consists of six main regions: the telencephalon (cerebral hemispheres), diencephalon (thalamus and hypothalamus), mesencephalon (midbrain), cerebellum, pons, and medulla oblongata. Each of these areas in turn has a complex internal structure.

The cerebral hemispheres are two i.e the right and the left. For most of the activities of the body, there is contra lateral innervation as opposed to ipsilateral innervations except for the cerebellum. This simply means that the left side of the body is controlled by the right side of the telencempalon and vice vesa.

The diecephalon consists of the thalamus and hypothalamus. The hypothalamus performs numerous vital functions, most of which relate directly or indirectly to the regulation of visceral activities by way of other brain regions and the autonomic nervous system. The thalamus has multiple functions. Most nerve fibers going to the cerebrum pass through the thalamus.

The cerebellum also called little brain is a region of the brain that plays an important role in motor control. It is also involved in some cognitive functions such as attention and language, and probably in some emotional functions such as regulating fear and pleasure responses. Its movement-related functions are the most clearly understood, however. The cerebellum does not initiate movement, but it contributes to coordination, precision, and accurate timing. It receives input from sensory systems and from other parts of the brain and spinal cord, and integrates these inputs to fine tune motor activity. Because of this fine-tuning function, damage to the cerebellum does not cause paralysis, but instead produces disorders in fine movement, equilibrium, posture, and motor learning.

The mesencephalon is considered part of the brainstem. Its substantia nigra is closely associated with motor system pathways of the basal ganglia.

Dopamine produced in the substantia nigra plays a role in motivation and habituation of species from humans to the most elementary animals such as insects.

The pons measures about 2.5 cm in length. Most of it appears as a broad anterior bulge rostral to the medulla. Posteriorly, it consists mainly of two pairs of thick stalks called cerebellar peduncles. The pons contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture. Within the pons is the pneumotaxic center, a nucleus in the pons that regulates the change from inspiration to expiration. The pons also contains the sleep paralysis center of the brain as well as generating the dreams of REM sleep.

 

The medulla oblongata is the lower half of the brainstem. It controls autonomic functions, and relays nerve signals between the brain and spinal cord. It is also responsible for controlling several major points and autonomic functions of the body like, respiration by chemoreceptors, cardiac center for sympathetic and parasympathetic system, vasomotor center by baroreceptors and reflex centers of vomiting, coughing, sneezing, and swallowing.

Out of all the parts of the brain the cerebral cortex is very much involved in motor functions. The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different composition in terms of neurons and connectivity. The human cerebral cortex is 2–4 mm (0.08–0.16 inches) thick. Further it is the part of the brain that contains the lobes.

The human brain contains four (4) anatomical lobes on both sides of the brain. The Frontal lobe is concerned with conscious thought; damage can result in mood changes. Parietal lobe plays an important role in integrating sensory information from various senses, and in the manipulation of objects; portions of the parietal lobe are involved with visuospatial processing. The Occipital lobe has the sense of sight; lesions can produce hallucinations and the Temporal lobe has the sense of smell and sound, as well as processing of complex stimuli like faces and scenes.

The brain ends inferiorly by a tail like structure, the spinal cord. This runs through the vertebral bones where it is protected from mechanical injury.

 

CEREBRAL PALSY

The term cerebral palsy refers to any one of a number of neurological disorders that appear in infancy or early childhood and permanently affect body movement and muscle coordination but don’t worsen over time. Even though cerebral palsy affects muscle movement, it is not caused by problems in the muscles or nerves.  It is caused by abnormalities in parts of the brain that control muscle movements.  The majority of children with cerebral palsy are born with it, although it may not be detected until months or years later. The term cerebral palsy (CP) was originally coined more than a century ago and loosely translates as "brain paralysis." However, a precise definition has remained elusive because cerebral palsy is not a single diagnosis but a collection of conditions that develops during pregnancy, childbirth, and early childhood up to about age three.

Cerebral palsy (CP) is divided into four major classifications to describe different movement impairments. These classifications also reflect the areas of the brain that are damaged. Paneth, (2007) the four major classifications are: Spastic, Ataxic, Athetoid/dyskinetic and Hypotonic.

SPASTIC CEREBRAL PALS

The most common type of overall cerebral palsy, occurring in 70% to 80% of all cases. People with this type of CP are hypertonic. It is characterized by spasticity (velocity-dependent increase in tone), hyperreflexia, clonus, and an up going Babinski reflex. Pathologically, it results when there is an insult to the cortex or pyramidal tract.

ATAXIC

Ataxia type symptoms can be caused by damage to the cerebellum. The forms of ataxia are less common types of cerebral palsy, occurring in at most 10% of all cases. Some of these individuals have hypotonia and tremors.

Motor skills such as writing, typing, or using scissors might be affected, as well as balance, especially while walking. It is common for individuals to have difficulty with visual and/or auditory processing.

ATHETOID CEREBRAL PALSY

Athetoid or dyskinetic cerebral palsy is mixed muscle tone, thus both hypertonia and hypotonia. People with athetoid CP have trouble holding themselves in an upright, steady position for sitting or walking, and often show involuntary motions. It takes a lot of work and concentration to get their hand to a certain spot. Because of their mixed tone and trouble keeping a position, they may not be able to hold onto objects, especially small ones requiring fine motor control. About one-quarter of all people with CP have athetoid CP i.e it occurs in 10% to 20% of all cases. The damage occurs to the extrapyramidal motor system and/or pyramidal tract and to the basal ganglia. High bilirubin levels in the blood of infants, if left untreated, can lead to brain damage in certain areas (kernicterus), which can lead to athetoid cerebral palsy.

HYPOTONIC CEREBRAL PALSY

Hypotonia is the opposite of hypertonia. People with hypotonic CP have musculature that is limp, and can move only a little or not at all.

CAUSES OF CEREBRAL PALSY

Causes of cerebral palsy can be grouped in three. These are pre- natal, peri – natal and post –natal causes.

Pre – natal causes - The majority of children with cerebral palsy are born with it, although it may not be detected until months or years later.  This is called congenital cerebral palsy. This can be due to the mother having malaria leading to reduced red blood cells in the blood. Other causes may be HIV status of the mother and the social aspect of the mother i.e if the mother drinks alcohol or smokes. Trauma and poisoning of mother can also result in cerebral palsy.

Peri – natal - This is among the acquired causes of cerebral palsy (CP). It describes the acquisition of cerebral palsy due to the activities that take place at the time of birth of the child. Surgical operation or any other trauma due to the use of forceps, breech presentation, prolonged labor and birth asphyxia are the most peri – natal causes of CP.

Post – natal - This is attributed to the causes of CP from the time the baby is born to about three years of age. Infection of the baby by malaria, TB, meningitis, and sexually transmitted infections are the common causes.

RISK FACTORS

Just as there are particular types of brain damage that cause cerebral palsy, there are also certain medical conditions or events that can happen during pregnancy and delivery that will increase a baby’s risk of being born with cerebral palsy. These are:

Ø  Low birth weight and premature birth: Weigh less than pounds at birth or are born less than 37 weeks into pregnancy.

Ø  Multiple births: Twins, triplets, and other multiple births even those born at term increase the risks. The death of a baby’s twin or triplet further increases the risk.

Ø  Infections during pregnancy: Diseases caused by viruses, such as toxoplasmosis, rubella (German measles), cytomegalovirus, and herpes, can infect the womb and placenta.

Ø  Blood type incompatibility: Rh incompatibility is a condition that develops when a mother’s Rh blood type (either positive or negative) is different from the blood type of her baby.  Because blood cells from the baby and mother mix during pregnancy, if a mother is negative and her baby positive, for example, the mother’s system won’t tolerate the presence of Rh-positive red blood cells.  Her body will begin to make antibodies that will attack and kill her baby’s blood cells.

Ø  Exposure to toxic substances: Mothers who have been exposed to toxic substances during pregnancy, such as methyl mercury, are at a heightened risk of having a baby with cerebral palsy. 

Ø  Thyroid abnormalities, mental retardation, and seizures  

Ø  Breech presentation: Babies with cerebral palsy are more likely to be in a breech position (feet first) instead of head first at the beginning of labor.

Ø  Complicated labor and delivery: A baby who has vascular or respiratory problems during labor and delivery may already have suffered brain damage or abnormalities.

Ø  Small for gestational age: Babies born smaller than normal for their gestational age are at risk for cerebral palsy because of factors that kept them from growing naturally in the womb.

Ø  Low Apgar score: checks a baby's heart rate, breathing, muscle tone, reflexes, and skin color during the first minutes after birth.

Ø  Jaundice: Bilirubin, a substance normally found in bile, builds up faster than the baby’s Liver can break it down and pass it from the body. This produces a condition called kernicterus, which kills brain cells and can cause deafness and cerebral palsy. 

Ø  Seizures: An infant who has seizures faces a higher risk of being diagnosed later in childhood with cerebral palsy. (National Institute of Neurological Disorders and Stroke, 2011)

DIAGNOSIS

The diagnosis of cerebral palsy has historically rested on the patient's history and physical examination. Once diagnosed with cerebral palsy, further diagnostic tests are optional. CT or MRI is warranted when the etiology of a patient's cerebral palsy has not been established - an MRI is preferred over CT due to diagnostic yield and safety. When abnormal, the neuroimaging study can suggest the timing of the initial damage. The CT or MRI is also capable of revealing treatable conditions, such as hydrocephalus, porencephaly, arteriovenous malformation, subdural hematomas and hygromas, and a vermian tumor. Furthermore, an abnormal neuroimaging study indicates a high likelihood of associated conditions, such as epilepsy and mental retardation. Ashwal et al. (2004)

SIGNS AND SYMPTOMS

The signs of cerebral palsy usually appear in the early months of life, although specific diagnosis is usually delayed until later.  Parents are often the first to suspect that their baby’s motor skills aren’t developing normally. Infants with cerebral palsy frequently have developmental delay, in which they are slow to reach developmental milestones such as learning to roll over, sit, crawl, smile, or walk.   Some infants with cerebral palsy have abnormal muscle tone as infants. Decreased muscle tone (hypotonia) can make them appear relaxed, even floppy. Increased muscle tone (hypertonia) can make them seem stiff or rigid. In some cases, an early period of hypotonia will progress to hypertonia after the first 2 to 3 months of life. Children with cerebral palsy may also have unusual posture or favor one side of the body when they move.

PROGNOSIS

Cerebral palsy doesn’t always cause profound disabilities.   While one child with severe cerebral palsy might be unable to walk and need extensive, lifelong care, another with mild cerebral palsy might be only slightly awkward and require no special assistance. Supportive treatments, medications, and surgery can help many individuals improve their motor skills and ability to communicate with the world.

MANAGEMENT

Cerebral palsy can’t be cured, but treatment will often improve a child's capabilities.   Many children go on to enjoy near-normal adult lives if their disabilities are properly managed. In general, the earlier treatment begins the better chance children have of overcoming developmental disabilities or learning new ways to accomplish the tasks that challenge them. There is no standard therapy that works for every individual with cerebral palsy. A comprehensive management plan will pull in a combination of health professionals with expert knowledge. Management of CP involves medical and surgical intervention and physiotherapy management.

MEDICAL INTERVENTION

Oral medications such as diazepam, baclofen, dantrolene sodium, and tizanidine are usually used as the first line of treatment to relax stiff, contracted, or overactive muscles.

Injections of alcohol into muscles to reduce spasticity. The benefits last from a few months to 2 years or more, but the adverse effects include a significant risk of pain or numbness, and the procedure requires a high degree of skill to target the nerve.

Botulinum toxin (BT-A), injected locally, has become a standard treatment for overactive muscles in children with spastic movement disorders such as cerebral palsy.  BT-A relaxes contracted muscles by keeping nerve cells from over-activating muscle.  A number of studies have shown that it reduces spasticity and increases the range of motion of the muscles it targets.

The relaxing effect of a BT-A injection lasts approximately 3 months.  Undesirable side effects are mild and short-lived, consisting of pain upon injection and occasionally mild flu-like symptoms.  BT-A injections are most effective when followed by a stretching program including physical therapy and splinting.    BT-A injections work best for children who have some control over their motor movements and have a limited number of muscles to treat, none of which is fixed or rigid. 

Intrathecal baclofen therapy uses an implantable pump to deliver baclofen, a muscle relaxant, into the fluid surrounding the spinal cord.  Baclofen works by decreasing the excitability of nerve cells in the spinal cord, which then reduces muscle spasticity throughout the body.  Because it is delivered directly into the nervous system, the intrathecal dose of baclofen can be as low as one one-hundredth of the oral dose.  Studies have shown it reduces spasticity and pain and improves sleep.

 

SURGICAL INTERVENTION

Orthopedic surgery is often recommended when spasticity and stiffness are severe enough to make walking and moving about difficult or painful.  For many people with cerebral palsy, improving the appearance of how they walk – their gait – is also important.  A more upright gait with smoother transitions and foot placements is the primary goal for many children and young adults.

 Selective dorsal rhizotomy (SDR) is a surgical procedure recommended only for cases of severe spasticity when all of the more conservative treatments – physical therapy, oral medications, and intrathecal baclofen -- have failed to reduce spasticity or chronic pain.  In the procedure, a surgeon locates and selectively severs over activated nerves at the base of the spinal column.

 

PHYSIOTHERAPY MANAGEMENT

Physical therapy, usually begin in the first few years of life or soon after the diagnosis is made.  It is a cornerstone of cerebral palsy treatment. Physical therapy programs use specific sets of exercises and activities to work toward two important goals: preventing weakening or deterioration in the muscles that are not being used (disuse atrophy), and keeping muscles from becoming fixed in a rigid, abnormal position (contracture).

Resistive exercise programs (also called strength training) and other types of exercise are often used to increase muscle performance, especially in children and adolescents with mild cerebral palsy.  Daily bouts of exercise keep muscles that are not normally used moving and active and less prone to wasting away.  Exercise also reduces the risk of contractures, one of the most common and serious complications of cerebral palsy.

Normally growing children stretch their muscles and tendons as they run, walk, and move through their daily activities.  This insures that their muscles grow at the same rate as their bones. But in children with cerebral palsy, spasticity prevents muscles from stretching.  As a result, their muscles do not grow fast enough to keep up with their lengthening bones.  The muscle contracture that results can set back the gains in function they have made.  Physical therapy alone or in combination with special braces (called orthotic devices) helps prevent contracture by stretching spastic muscles.

The Bobath technique has had a widespread influence on the core physical therapies of cerebral palsy treatment

ALTENATIVE DEVICES

Occupational therapy.  This kind of therapy focuses on optimizing upper body function, improving posture, and making the most of a child’s mobility.  An occupational therapist helps a child master the basic activities of daily living, such as eating, dressing, and using the bathroom alone.  Fostering this kind of independence boosts self-reliance and self-esteem, and also helps reduce demands on parents and caregivers.

Spinal cord stimulation was developed in the 1980s to treat spinal cord injury and other neurological conditions involving motor neurons.  An implanted electrode selectively stimulates nerves at the base of the spinal cord to inhibit and decrease nerve activity.   The effectiveness of spinal cord stimulation for the treatment of cerebral palsy has yet to be proven in clinical studies.  It is considered a treatment alternative only when other conservative or surgical treatments have been unsuccessful at relaxing muscles or relieving pain.

Other alternative therapies are involved at different times in the management of CP. These may include speech therapy, Therapeutic (subthreshold) electrical stimulation, Threshold electrical stimulation, Hyperbaric oxygen therapy