A second form of motor disorder is characterized by the development of severe spastic quadriplegia and developmental delay. The major insult is usually intrapartum asphyxia and attendant fetal distress. Usually such infants will have required resuscitation and will have had low 5-min Apgar scores and seizures, which have important predictive value in this circumstance. The pathologic lesions of the brain in this second group consist of hypoxic-ischemic infarction in distal fields of arterial flow, primarily in the cortex and white matter of parietal and posterior frontal lobes, leaving an ulegyric sclerotic cortex.
A third group, discussed below, is characterized mainly by extrapyramidal abnormalities, combining athetosis, dystonia, and ataxia in various proportions. After reviewing the results of several large series of congenital and neonatal motor disorders, we have concluded that spastic diplegia occurs in 10 to 33 percent of cases, spastic quadriplegia in 19 to 43 percent, extrapyramidal forms in 10 to 22 percent, and mixed forms in 9 to 20 percent.
Spastic diplegia (“Little disease”) The pattern of paralysis is more variable than the term spastic diplegia implies; actually, several subtypes may be distinguished: paraplegic, diplegic, quadriplegic, pseudobulbar, and generalized. Pure paraplegic and pseudobulbar types are relatively rare. The eponymic “Little disease” has been applied mainly to the spastic diplegic type, but it also has been attached to all forms of motor cerebral palsy in some older writings.
Usually all four extremities are affected, but the legs much more than the arms, which is the real meaning of diplegia. Hypotonia—with retained tendon reflexes and hypoactivity—is usually present initially. Only after the first few months will evident weakness and spasticity appear, first in the adductors of the legs. The plantar reflexes, which often take on ambiguous direction in the normal infant, here are clearly extensor, a finding that is pathologic at any later age. Also, stiff, awkward movements of the legs, which are maintained in an extended, adducted posture when the infant is lifted by the axillae, often do not attract attention until several weeks or months have passed. Seizures occur in approximately one-third of the cases, and it is not uncommon to observe a delay in all developmental sequences, especially those that depend on the motor system.
Once walking is attempted, usually at a much later date than usual, the characteristic stance and gait become manifest. The slightly flexed legs are advanced stiffly in short steps, each describing part of an arc of a circle; adduction of the thighs is often so strong that the legs may actually cross (scissors gait); the feet are flexed and turned in with the heels not touching the floor. In the adolescent and adult, the legs tend to be short and small, but the muscles are not markedly atrophic, as they are in spinal muscular atrophy. Passive manipulation of the limbs reveals spasticity in the extensors and adductors and slight shortening of the calf muscles. The arms may be affected only slightly or not at all, but there may be awkwardness and stiffness of the fingers and, in a few, pronounced weakness and spasticity. In reaching for an object, the hand may overpronate and a grasp may be difficult to release. Speech may be well articulated or noticeably slurred, and in some instances the face is set in a spastic smile. Scoliosis is frequent and may secondarily give rise to root compression and impaired respiratory function. As a rule, there is no disturbance of sphincteric function, although delay in acquiring voluntary bowel and bladder control is usual. Athetotic postures and movements of the face, tongue, and hands are present in some patients and may actually conceal the spastic weakness.