Classification of CP subtypes
The classification of CP subtypes is based on clinical features and made of the basis of the predominant neurological finding.
It identifies three main groups: spastic, dyskinesic and ataxic cerebral palsy.
All CP subtypes have in common an abnormal pattern of movement and posture.
Additional features include:
Spastic CP is characterised by
- Increased tone
- Pathological reflexes (increased reflexes, e.g. hyperreflexia and pyramidal signs e.g. Babinski response)
- Resulting in abnormal pattern of posture and/or movement
It may be unilateral (US-CP - hemiplegia) or bilateral (BS-CP – diplegia and tetraplegia).
Dyskinetic CP is characterised by
- Involuntary, uncontrolled, recurring, occasionally stereotyped movements, primitive reflex patterns predominate, muscle tone is varying
SCPE uses the following definitions for subgrouping dyskinetic CP:
1. Dystonic CP is dominated by
- abnormal postures (may give the impression of hypokinesia)
- hypertonia (tone fluctuating, but easily elicitable tone increase).
Characteristic are involuntary movements, distorted voluntary movements and abnormal postures due to sustained muscle contractions (slow rotation, extension, flexion of body parts).
2. Choreo-athetotic CP is dominated by
- hypotonia (tone fluctuating, but mainly decreased).
Chorea means rapid involuntary, jerky, often fragmented movements.
Athetosis means slower, constantly changing, writhing or contorting movements.
Pure dyskinetic movement disorder does not show hyperreflexia with clonus, nor pyramidal signs. But in dyskinetic CP these signs of spastic disorder may be present. The dominating features should determine subtype classification.
Ataxic CP is characterised by
- Loss of orderly muscular co-ordination, so that movements are performed with abnormal force, rhythm and accuracy
- Typical features are:
- trunk and gait ataxia – disturbed balance
- past pointing – over-, undershooting of goal directed movements
- tremor is another common sign – mainly a slow intention tremor
- low tone is also a predominant feature
The definition and inclusion/exclusion criteria were agreed upon at the 2nd SCPE plenary meeting, held in Oxford, July 1999, and published in Cans et al. (2000) DMCN (2000).