3 – Residual deficits following cerebral
circulatory arrest
Miller and Myers (1970) devised four categories to
describe the extent of residual neurological deficits in
asphyxiated monkeys:
Category 0 included animals considered to have only
minimal signs of permanent injury such as decreased
motor activity and slight clumsiness in use of the
hands. It is fair to ask if decreased activity and
impaired fine motor ability would not be considered
serious if it happened to us or one of our children. It
is not acceptable to be "within normal limits" defined
by experts who are not themselves affected.
Question authority; and demand honesty.
Category 1 included signs considered to be clear-cut
indications of neurological damage. The animals in
this category were able to sit unassisted but almost all
displayed distal clumsiness; animals with ataxia and
broad-based gait or other signs of motor weakness
were also assigned to this group. Some animals in
this group exhibited tolerance to abnormal limb
positioning (catatonia).
Category 2 included animals who were unable to sit
but who did respond to threat or other visual stimuli;
most exhibited marked muscular hypertonus and
episodes of opisthotonic posturing.
Category 3 animals remained comatose and failed to
respond to visual or other environmental stimuli.
Category 4 animals were considered to be
decerebrate.
Although residual problems of animals in categories 1
to 4 would seem quite serious, Miller and Myers
concluded there was "the possibility of virtually
complete recovery of function even after twenty
minutes of systemic circulatory arrest," [1, p723].
Although "transient or enduring ataxia, extensor
hypotonus, and oculomotor palsies suggest that the
cerebellum and the region of the brainstem may have
been prominently affected," Miller and Myers stated
that their findings support the feeling that "following
cerebral insult due to anoxia or ischemia, patients be
considered potentially salvageable," [1, p723].
- Miller JR, Myers RE
(1970) Neurological
effects of systemic
circulatory arrest in the
monkey.
Full reference
- Miller JR, Myers RE. Neurological effects of systemic circulatory arrests in the
monkey. Neurology. 1970 Jul;20(7):715-24.