Cerebral palsy is often characterized by the type of muscle tone
abnormality and the body parts involved (Table
53-3). The most common abnormality is that of increased muscle tone, or
spasticity. Spastic disorders affect approximately three-fourths of all patients
with CP.,
This spasticity can occur in either a consistent or velocity-dependent manner or
both. When the resistance to passive movement is continuous and constant despite
changes in limb velocity, the increased tone is called rigidity. This has often
been compared to the feel of bending a lead pipe.
There are frequently signs of the upper motor neuron syndrome
in CP (exaggerated muscle stretch reflexes and abnormal Babinski reflexes). There
can be "overflow" of muscle stretch reflexes to adjacent joints such as the crossed
adductor reflex (contraction of bilateral adductor muscles to unilateral adductor
stretch).
| Grades of Intraventricular Hemorrhage in the Premature Brain |
| Grade 1
- not recognized: entry |
|
Figure
53-1
A and B.
Periventricular leukomalacia.
Less common are dyskinetic disorders with involuntary movements.
Classic athetoid movements which encompass large muscle groups are common. The
involuntary, slow writhing posturing of athetosis is most easily detected in the
movements of the head and face. Dyskinetic
disorders cause impairments in postural instability, and are sometimes reflected
in "fluctuating tone" abnormalities. These patients often begin with hypotonia,
and develop the discrete involuntary movements over the first few years of life.
Athetoid disorders are most commonly caused by damage to the basal ganglia with
hyperbilirubinemia or severe anoxia. Small muscle involuntary movements such as
chorea can also be seen. Rarely, ballistic, rotary, and flailing movements have
been described. Ataxic disorders that mimic cerebellar
| Classification of Cerebral Palsy Types |
| By Tone Abnormalities
- not recognized: entry |
|---|
|
dysfunction with titubation, wide-based gait, and dysmetria are very rare in CP.
A small percentage of patients have the hypotonic type of CP.
These children need to be differentiated from those with more frequently identifiable
causes of neonatal hypotonia such as muscle disease, metabolic disorders, and genetic
syndromes. Many of these children develop spastic or extrapyramidal-type disorders
after the first few months of life. All of these tone abnormalities can occur in
mixtures. The most common combination is that of spasticity with athetosis. These
patients are sometimes classified as "mixed-type" CP.
The distribution of body parts with disability is used to name
the type of CP (Fig. 53-2
Fig. 53-3 Fig.
53-4). Diplegia refers to spastic paresis
in the lower extremities more than in the upper extremities, and is the most common.
Quadriplegia, involving abnormalities of both upper
and lower extremities, is also frequent. In quadriplegia the disorder of motor control
is typically worse in the legs. Rarely, a
child has obvious abnormalities of both legs and one arm, and is referred to as having
triplegia. Patterns of abnormalities that involve
an arm more than the ipsilateral leg (similar to a stroke) are labeled as hemiplegia.
For unclear reasons, isolated right hemiplegia is twice as common as left hemiplegia.
Diplegia, or leg-dominated symptoms, is most frequent in the low-birth-weight,
premature groups. Quadriplegia is more frequent in those with normal
Figure
53-2
Patient with spastic diplegia.
