Stroke is traditionally defined as a neurological deficit attributed to an acute focal injury
of the central nervous system (CNS), which occurs on a vascular basis.
Another localizing strategy is to place the invasive cerebral monitor in the vicinity of the lesion seen on imaging in cases of focal injury
with recent evidence of improvement in outcome .
Stroke is typically categorized as a neurological deficit because of an acute focal injury
to the central nervous system (CNS) by a vascular cause.1 Shoulder pain is considered a common secondary complication after stroke.
Briefly, 8 regions (anterior, middle, and posterior cortex, CA1, CA2, CA3, and dentate gyrus of the hippocampus, and striatum) were graded on a scale of 0 to 3 with 0 = no injury, 1 = few small areas of focal injury
, 2 = multiples areas of focal injury
, and 3 = widespread injury with loss of architecture.
"The whole brain was insulted, as opposed to a focal injury
to the head."
Work conducted in Cambridge by Gupta and colleagues shows good correlation between Pbt[O.sub.2] and jugular bulb blood oxygenation only in areas without focal injury
. In areas with focal injury
, the correlation is absent.
In the case of compartment injury, there are tissue pressure gradients from the centre to the periphery of focal injury
. As a result, different West zones exist in the same vascular network.
To some extent, these readings can be extrapolated when being measured in relatively uninjured brain, but if there is significant focal injury
the decision has to be made whether one should measure Pbt[O.sub.2] in the injured or uninjured tissue.
(7,8) Type 1 injury (incidence 0.3% to 2%) includes all major and moderate focal injury
(including coma and shock) due to major cerebral infarction.
An expanding, space-occupying lesion (eg, epidural hematoma) from a focal injury
may eventually result in unconsciousness, following a lucid interval, because of increasing intracranial pressure.
A focal injury
(an injury to a small part of the cerebellum) may affect only arm movements, balance, gait, or eye movements.
However, damage at a slightly later stage can mimic the action of a focus; thus, a focal injury
can increase the size of the small forewing eyespot, and an injury elsewhere can provoke formation of an ectopic eyespot.