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.
The whole brain was insulted, as opposed to a focal injury
to the head.
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.