Health

Classification Systems
There is much inconsistency in the classification of cerebral palsy.  Presented below are two systems that attempt to classify this spectrum of disorders.  

Traditional System
One way of classifying children with cerebral palsy is by dividing them into those with spastic,  dyskinetic, ataxic, hypotonic and mixed types.

Spastic Cerebral Palsy
Spastic cerebral palsy is by far the most common and is present in approximately 75 percent of all children with cerebral palsy. Spasticity is described as a velocity-dependent resistance to passive movement. This means that the faster you pull against a muscle, the harder it resists or pulls back. Spastic cerebral palsy is divided into diplegic, hemiplegic and quadriplegic/tetraplegic types. Diplegia shows an involvement of legs more than the arms and is the most common type of cerebral palsy. Many times the arms do not seem involved but exhibit at least small deficits in function. Hemiplegia is involvement of the arm and leg on the same side. Classically the arm is more involved but sometimes they seem equally involved. Quadriplegia or tetraplegia is involvement of both arms and both legs, generally worse in the legs than in the arms. In spastic cerebral palsy there are generally signs of upper motor-neuron involvement with increased muscle reflexes, upgoing toes and persistence of primitive reflexes such as the Moro response.

Dyskinetic Cerebral Palsy
A much less frequent type of cerebral palsy is the dyskinetic type. These children frequently are hypotonic initially and then develop discrete involuntary movements during the first several years of life. Dyskinetic movements include athetoid (writhing), dystonic (increased tone) or choreaform (jerky) movements. Historically before the early 1960s, 50 percent of children with athetoid cerebral palsy had hyperbilirubinemia (increased bilirubin, a breakdown product of red blood cells), due to Rh blood factor incompatibility. Since improvements in treatment of this including early exchange transfusions, this has become much less of a problem. With dystonia, abnormal movements have their origin in the basal ganglia, particularly the globus pallidus. These abnormal movements disappear in sleep and are worsened by stress. The dysarthria (difficult with speaking) with this can be dramatic.

Other Types of Cerebral Palsy
Ataxic (uncoordinated) and hypotonic (low muscle tone) cerebral palsy are rarer types.  Hypotonic cerebral palsy more frequently becomes ataxic, spastic or dystonic cerebral palsy with age. All of these may frequently show spasticity as well. Different combinations of the above types can be found and are called mixed cerebral palsy.

Proposed System
An international workshop was held in July 2004 to revisit the definition of cerebral palsy due to improvements in brain imaging; information about brain development and etiology; and concern that non-motor disabilities, performance and behavior were not being addressed in the definition. In addition, worsening musculoskeletal difficulties with age and activity restriction were not even part of the previous definition. Therefore, a broad-based working group came up with a definition that was made available for evaluation by the medical community, families and the public. Their definition was published in February 2007. The definition is as follows:

“Cerebral Palsy (CP) describes a group of permanent disorders of the development of movement and posture, causing activity limitations that are attributed to nonprogressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of CP are often accompanied by disturbances of sensation, perception, cognition, communication and behavior, by epilepsy and by secondary musculoskeletal problems.”

This definition emphasized again that cerebral palsy is a heterogeneous condition in terms of causes, types and severity. It purposefully was vague regarding the age of onset, though it implied the first two or three years of life.

Systematic classification aims to improve description, prognostication, comparison and evaluation of changes that happen as a person ages. Traditionally, the classification looked at the distribution of affected limbs and the problem of tone only. This was thought to be inadequate. In classifying children, it is now suggested that age is a critical part of the information because many findings will change as the child ages, including tone, cognition and even the appearance of the motor disorder.

The components of cerebral palsy classification now recommended are:

1.  Motor abnormalities to include a primary tone abnormality: the dominant type of tone should be listed as spasticity, dystonia, choreoathetosis or ataxia. 
2.  Functional motor abilities, including speech: the Gross Motor Function Classification System (GMFCS) is widely used to describe this component. 
3.  Accompanying impairments, including seizures and cognitive deficits: aside from the presence or absence of seizure disorder and IQ score, other problems such as corrected vision in each eye and hearing loss, should be described.
4.  Anatomical and neuroimaging findings with the distribution of affected segments: all body regions affected including the trunk and oropharynx should be described individually. It was felt that the terms diplegia and quadriplegia were too nonspecific and should be replaced. Classification as unilateral (one-sided) or bilateral (two-sided) is recommended. All neuroimaging findings are to be reported.
5.  Causation and timing if known: causation is not clearly known in many children, but the timing may be known in some and should be recorded. The etiology is unknown in approximately 15 percent of children even after neuroimaging and metabolic workup.

Gross Motor Function Classification System (GMFCS)
The Gross Motor Function Classification System (GMFCS) is used in conjunction with other classification systems (including the two above). 

The Gross Motor Function Classification System (GMFCS) for cerebral palsy was developed by Dr. Palisano in 1997. This was developed to quantify the severity of motor involvement in cerebral palsy, to improve communication and to make more specific predictions of outcome. The GMFCS was designed for classification of motor function in children with cerebral palsy through their twelfth year of life. There are five levels of GMFCS based on differences in self-initiated movement (particularly sitting and walking) depending on age group. There are several levels: before 2 years, between 2 and 4 years, between 4 and 6 years and 6 to 12 years of age with functional abilities and limitations at each level. There are five levels:

 Level I: can walk indoors and outdoors and climb stairs without limitations. They can perform usual activities such as running and jumping, but they have decreased speed, balance and coordination.
  
 Level II: can walk indoors and outdoors and climb stairs with a railing, but they have difficulty with uneven surfaces, inclines or in crowds. They have minimal ability to run or jump.

 Level III: have the ability to walk indoors and outdoors on a level surface with an assistive mobility device. They may be able to climb stairs using a railing. They may propel a manual wheelchair or require assistance to push their wheelchair for long distances or on uneven surfaces.

 Level IV: use a wheelchair most of the time and may propel their own power wheelchair.

 Level V: have physical impairments that restrict their voluntary control of movement and their ability to maintain head and neck position against gravity. They are impaired in all areas of motor function. They cannot sit or stand on their own even with equipment. They cannot do independent mobility, though some may be able to use a power wheelchair with extensive modifications and adaptations.