The modifications of the GCS you seek are in the FIRST (not the current)
edition of a book called 'The Scientific Foundations of Neurosurgery' ed.
Crockard et al., published by Blackwell. They are not in the current
edition as I suspect they are not in widespread use, there are several
modifications for different pediatric age groups and thus lack the
simplicity that makes for ease of application.
C. N. Pidgeon
Neurosurgeon