What Terms do Clinicians Use to Describe a Child’s Motor Picture and What do They Mean?
Because the clinical picture of CP can be highly variable in severity and the area of the child’s body affected by the condition, clinicians have tried to develop ways of describing the individual child’s motor picture for easier communication among health professionals as well as affording a prognosis and treatment. Traditionally, cerebral palsy has been classified by the type of muscle tone, and the areas of the body that have been affected, and the severity of the impairments (mild, moderate and severe). Recently a variety of new tools have been developed to describe a child’s clinical picture. These include the Gross Motor Function Classification System, which has been used to classify cerebral palsy in terms of child’s gross motor function and mobility at different age ranges.
Describing a Child’s Cerebral Palsy
The terms below have historically been used by clinicians to describe the motor involvement in child with CP. However, the reproducibility of these terms across clinical settings is sometimes a challenge.
- Muscle tone may be increased or decreased in children with CP.
- Spasticity is one type of increased muscle tone. It is characterized by being velocity-dependent. This is determined by passively flexing and extending muscle groups across a joint. If a person has spasticity in the muscle being examined, the clinician will feel resistance to movement when it is ranged and the resistance will be more prominent if the limb is ranged quickly compared to slowly. Children with spasticity often have more pronounced deep tendon reflexes, clonus (repetitive beats of the ankle when it is moved rapidly) and extensor plantar responses (the big toe turns up when the bottom of the foot is stroked). However, the latter are sometimes difficult to elicit in the infant and even in the older child with spastic cerebral palsy. A satisfactory, reproducible system of grading muscle tone has never been developed, although the Ashworth and Tardieu scales are commonly used in research.
- Dyskinesia is defined as abnormal motor movements. When the patient with dyskinesia is totally relaxed lying on their back, a full range of motion and decreased muscle tone may be found. However, when they attempt voluntary movements, the dyskinesia becomes evident. Patients may have two different features of dyskinesia. The child with hyperkinetic or choreo-athetoid movements show purposeless, often massive involuntary movements with motor overflow, that is, the initiation of a movement of one muscle group leads to movement of other muscle groups. The child with dystonia manifests abnormal shifts of general muscle tone induced by movement. Typically, these children assume and retain abnormal and distorted postures in a stereotyped pattern. Dystonia creates resistance to range of motion at joints and high tone but dystonia is not velocity dependent so the resistance to range of motion will be significant even if the muscle is ranged slowly. However, the extent of dystonia can vary significantly based upon the child’s state of alertness and agitation. When the child is asleep, the dystonia my not be felt at all. If the child is upset and agitated, the dystonia will be prominent. Both types of dyskinesia may occur in the same patient.
- Ataxias. Patients with ataxias have poor coordination of voluntary movements. These patients may be hypotonic during the first two or three years of life. They commonly walk with a wide-based staggering gait and have poor accuracy when attempting to reach for something with their hands (called dysmetria).
Sometimes patients with CP have a complex picture with features of high and low muscle tone (e.g. low muscle tone in the trunk and high muscle tone in the extremities) and they may have a combination spasticity and dystonia. Some of these patients may also have ataxia. Sometimes clinicians will use the term Mixed CP to describe the child’s clinical picture.
For children with spasticity, sometimes terms are used to describe the areas of the body involved. These terms include:
- Diplegia refers to involvement predominantly of the legs although children with diplegia always have involvement in the arms to a lesser extent.
- Quadriplegia refers to dysfunction of all four extremities and arms/legs are involved equally or the arms somewhat more than the legs (in some children one upper extremity might be less involved; the term triplegia then would be substituted.
- Hemiplegia refers to individuals with unilateral motor dysfunction; and in most children the upper extremity is more severely involved than the lower.
- Double hemiplegia is an unusual situation may occur where the upper extremities are much more involved than the lowers; the term double.
Does the possibility that your child may develop cerebral palsy influence your behavior as a parent?
Talk to other parents in the My Child Without Limits support community, about how they deal with their concerns that their child will get CP.
Brain Injury Research Foundation
National Institute of Neurological Disorders and Stroke
Children’s Hemiplegia and Stroke Association