July 2004
6
Ischemic
brain damage
target of respiratory blood flow
after birth. Waiting for the infant to breathe
on its own is the best indicator that circulation has shifted from placental to pulmonary
respiration.
6. Ischemic brain damage
In experiments with monkeys on asphyxia at birth, the first
breath was prevented
by delivering the newborn head into a rubber sac, and placental respiration stopped by clamping the umbilical
cord [65-71]. The purpose was to investigate ways to prevent cerebral palsy, but the
asphyxiated monkeys did not develop cerebral palsy, and what Myers termed "a
monotonous rank order of brainstem lesions" was the pattern of damage found in the brain
[70]. Myers later found that prolonged
partial obstruction of placental blood flow late in gestation was the cause of cerebral palsy and
its well-known
pattern of damage to cortical and subcortical motor systems.
Windle proposed that the
brainstem pattern caused by
suffocation and umbilical cord
clamping at birth might underlie the syndrome
known at that time as "minimal cerebral
dysfunction" [67, 71]. So-called minimal involvement of the central nervous system corresponds to present-day designations of "attention deficit disorder"
or "pervasive
developmental disorder," behaviorally-defined
syndromes without involvement
of motor systems.
The midbrain auditory nucleus,
the inferior colliculus,
sustained the most severe damage
in monkeys subjected to suffocation with
umbilical cord clamping. The monkeys were not deaf, but they did not orient to sounds the way normal monkeys do [67, 69].
The ability to learn language
"by ear" as most children do should be investigated as the possible result of such
damage to the auditory system at birth.
The most serious
