Clinical Features and Management of Cerebral Palsy

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CHAPTER 225 Clinical Features and Management of Cerebral Palsy

Janice E. Brunstrom-Hernandez, Ann Tilton

Cerebral palsy (CP) is “a group of disorders affecting the development of movement and posture, causing activity limitation, 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 behavioral and/or by a seizure disorder.”¹

The estimated prevalence of CP is 1.5 to 3.0 per 1000 live births worldwide, with differences among countries, racial/ethnic groups, and socioeconomic classes.^2,³ In most cases the cause of CP is not well defined, and it may vary with the subtype; prematurity and low birth weight are major risk factors for CP, especially bilateral spastic CP associated with periventricular white matter injury. Although birth asphyxia is uncommon, it is associated with the dyskinetic CP subtypes.³ Multiple genetic and metabolic factors may predispose infants to an increased risk for brain injury and CP.⁴

Diagnosis and Classification

Children with CP have a delay in motor development and abnormal motor findings on examination. Evaluation begins with a detailed history and physical and neurological examination, including careful documentation of prenatal, perinatal, and neonatal events and risk factors, developmental milestones, family history, general medical history, and a detailed survey to look for associated impairments (e.g., seizures, language disturbance, vision and hearing loss, nutritional difficulties). All CP patients should undergo magnetic resonance imaging, which may help reveal the underlying brain injury,⁵ although neither imaging nor laboratory tests can prove the diagnosis. An atypical history, clinical features, or imaging findings should trigger further evaluation, especially if there is any history of developmental regression or loss of skills.^3,⁶ Disorders that masquerade as CP include familial spastic paraparesis and dopa-responsive dystonia. Some patients, including those with typical risk factors for CP (twin gestation, prematurity, periventricular leukomalacia) have “CP plus” and are found to have a coexisting metabolic disorder (e.g., mitochondrial encephalomyopathy).

There is currently no universally accepted classification system for CP, but since the mid-1900s, CP has most commonly been classified into “spastic” or “dyskinetic” subtypes based on the predominant type of tone abnormalities or movement disorders, or both, present. Spastic CP is the most common and is further divided into spastic diplegia (legs more than the arms), spastic quadriplegia (arms equal to or more than the legs), and spastic hemiplegia (involvement of one side of the body). Dyskinetic CP is divided into dystonic and choreoathetoid forms. A small subset of patients may be classified as ataxic. However, there is great disparity among practitioners regarding the use of these terms, such that a given patient may be classified differently by different clinicians.⁷ This is a major weakness in the field, and correcting it is a priority for furthering research and treatment.

In 2000, the Surveillance for Cerebral Palsy in Europe group adopted a standardized system for database and registry purposes that is used throughout Europe and Australia. Patients are classified as “spastic bilateral” or “spastic unilateral.” Individuals with variable tone are classified as “dyskinetic” and then further classified as dystonic or choreoathetoid/hyperkinetic. Those with hypotonia and ataxia are classified as “ataxic.” Some patients are nonclassifiable. Additionally, clinically useful functional scales for both gross motor function (Gross Motor Function Classification Scale [GMFCS],⁸ Functional Mobility Scale⁹) and fine motor/hand function (Manual Ability Classification Scale,¹⁰ Bimanual Function Measure¹¹) are now available to allow improved description of motor function in patients with CP. A Communication Function Classification System is currently being validated (M. J. Cooley Hidecker, personal communication).

The clinical description of a patient with CP should include a detailed account of the movement disorder and tone abnormalities (e.g., spasticity, dystonia, athetosis, chorea, myoclonus), the presence of abnormally persistent primitive reflexes (startle, asymmetric tonic neck reflex) and absence of protective reflexes (parachute), assessment of muscle strength when possible (although a patient’s inability to isolate specific muscle groups may limit such assessment), topography of the movement disorder (limbs and body parts involved and how they are affected), motor function (including use of the aforementioned scales), and secondary musculoskeletal impairments (osteopenia, fracture, scoliosis, hip dysplasia, muscle contractures, bony deformities) that may further compromise mobility and quality of life. Most patients have multiple impairments. Dissecting out and treating, as possible, the various abnormalities will have the biggest impact on future motor outcome.

Associated Impairments

Although the hallmark of CP is the motor disorder, nearly all children with CP have one or more associated impairments that may impede their functional abilities, health, and overall quality of life; they often prove more detrimental than the motor disability. Associated neurological impairments (e.g., vision, hearing, and sensory deficits, epilepsy) can be attributed to brain/nervous system injury that extends beyond the motor system. Other impairments (e.g., musculoskeletal deformities, contractures, fractures, pain) may be secondary to spasticity, other movement disorders, and immobility. Several health impairments in children with CP may have a neurogenic component and can also be further exacerbated by the impaired mobility (e.g., bladder dysfunction, disorders of intestinal motility, sleep disorders). Every child with CP deserves a systematic and detailed survey to identify associated impairments because appropriate treatment can be life changing.

Neurological Impairments

Sensation

Visual disorders are common in children with CP but are often missed or inaccurately diagnosed.¹² Over half of children with spastic CP and no obvious visual deficit will nonetheless have visual perception disorders.¹³ The severity of the visual deficit tends to correlate with the severity of CP involvement and is increased with a history of prematurity, severity of periventricular leukomalacia, and the presence of dyskinetic CP.^12,¹⁴

Children with multiple visual impairments are often misdiagnosed as having untreatable “cortical visual impairment,” which leads to devastating consequences on communication, learning, social interactions, and quality of life. True cortical visual impairment affects approximately 16% of patients.¹² Detailed assessment may be required to untangle the various contributors to the visual impairment but may lead to dramatic improvement in vision through surgery (e.g., strabismus correction, lens replacement, laser treatment) and corrective lenses.

Hearing impairments occur in approximately 7% of children with CP but are likely to be missed, especially in nonverbal children.

Even children with the mildest spastic CP are likely to have deficits in tactile and proprioceptive sensation,¹⁵ and their severity may correlate with the severity of the motor dysfunction.¹⁶

Communication

Communication difficulties are present in nearly 60% of all patients with CP, including up to 90% of children with quadriplegic or dyskinetic CP, or both.¹⁷

Epilepsy

Approximately a third of all children with CP have epilepsy. The prevalence varies with the subtype of CP, from 16% in children with diplegic CP to 50% in those with quadriplegic CP.¹⁷ The prognosis depends on the subtype of CP, brain imaging abnormality, and cognitive ability. Children with CP and epilepsy are much less likely to achieve freedom from seizures with or without antiepileptic drugs, and they are more likely to require polytherapy.¹⁸

Cognition/Behavior

Median intelligence quotient (IQ) scores are lower in children with CP, with 40% to 65% having an estimated IQ of less than 70. Detailed neuropsychological testing should be performed before a child starts school. Accurate assessment is difficult if not impossible in many children because of their multiple other impairments. Thus, low estimates of intellect should be interpreted cautiously. Children with severe CP and limited or absent communication skills often have spared nonverbal reasoning abilities. Conversely, nonverbal learning disorders may be missed in a child with superior verbal skills.¹⁹

Health Impairments

Impaired motor function leads to significant health problems. Children with severe mobility impairments tend to be less healthy and spend more time in bed and more days in the hospital, are more likely to be malnourished, and are often taking more medications than their nondisabled peers.^20,²¹ Additionally, risk for fracture, hip dislocation, and scoliosis is elevated in nonambulatory patients with CP.²²^–²⁴

Gastrointestinal

Moderate gastrointestinal symptoms occur in up to 90% of children with CP, including one or more of the following: drooling, swallowing problems (30% to 60%), regular vomiting (30%), gastroesophageal reflux disease, and delayed gastric emptying (70%).²⁵^–²⁸ Even mild feeding dysfunction is significant and associated with lower body weight and reduced body fat stores.

Renal

Approximately two thirds of patients with CP have symptoms of voiding dysfunction, including difficulty voiding and daytime urinary incontinence. The prevalence of significant pathology (increased detrusor muscle contraction, reduced detrusor muscle compliance, reduced bladder capacity, inability to relax the external urethral sphincter, and high postvoid residuals) may be as high as 97%²⁹^–³³ and can increase the risk for progressive decline in upper urinary tract function and renal disease.^34,³⁵ Urinary tract infections are also common in children with CP^29,³⁶ and can lead to scarring and chronic renal insufficiency.³⁷

Improving Mobility and Motor Function (“I Want to Walk”): How Do We Help Them?

Improving a child’s ability to move is a major goal for most parents (and children). Children enjoy moving! The secondary consequences of immobility are high. Most children with CP have inadequate physical fitness, which further contributes to their poor health, pain, and secondary impairments.³⁸

Physical and Occupational Therapy

Physical and occupational therapy occurs in many different settings, including traditional (home, school, private clinic) and nontraditional (e.g., therapeutic horseback riding ^39,⁴⁰ and adapted sports). The therapist has a pivotal role as a teacher to help patients master new motor skills and teach parents (and older patients) exercises (stretching, strengthening, balance) and adaptive techniques (assistive technology for activities of daily living, access to computers or communication devices) that they can integrate into their daily life.

A variety of new tools are available to the physical therapist, such as electrical stimulation, which may have a positive effect on range of motion,⁴¹^–⁴³ and treadmill training with partial body weight support, which may be beneficial for a moderately severely impaired child (GMFCS III or IV).⁴⁴ Ankle-foot orthoses are commonly prescribed for children who have a dynamic equinus abnormality, may be more effective in younger children,⁴⁵ and can improve their ability to perform sit-to-stand transitions.⁴⁶ The most effective type and “dose” or frequency of physical therapy remains controversial. Recent studies suggest that intermittent bursts of intense therapy for a few weeks with several weeks off between sessions may be as effective as continuous therapy 1 to 2 times per week.⁴⁷

In the upper extremity, constraint-induced therapy and forced use have re-emerged as a useful tool. In clinical trials, restraint of the child’s better functioning hand/upper limb in combination with occupational therapy improves function in the affected limb (new motor skills and increased dexterity) for at least 6 months.⁴⁸^–⁵² Repeat courses of treatment lead to additional improvement.⁵³ Botulinum neurotoxin (BoNT) combined with occupational therapy is another effective strategy.⁵⁴ Recent, exciting advances include the use of robotics to improve upper extremity function.⁵⁵

Therapy programs along with overall management of a child’s hypertonia and mobility impairments must be goal-driven and tailored specifically to each child’s needs (Table 225-1). For example, children with spasticity need regular stretching of spastic muscles to optimize range of motion and prevent contractures. Strengthening exercises to reverse disuse atrophy may improve gait and do not worsen the spasticity.⁵⁶^–⁵⁹ Conversely, in children with generalized dystonia and hyperkinetic CP who are constantly moving or contracting their muscles, both stretching and strengthening may prove impractical if not impossible.

TABLE 225-1 Therapeutic Approach to Patients with Cerebral Palsy Based on Distribution and Severity*