Grading Scales for Subarachnoid Hemorrhage - Animal Models of Acute Neurological Injuries: Injury and Mechanistic Assessments - page 282

4. Glasgow Coma
Score

The Glasgow Coma Score (GCS) was developed in the early 1970s
as a mechanism to assess level of consciousness after a head injury
using a three axes system of eyes, verbal, and motor response
(Table 2 ) ( 12 ). Throughout the years, the GCS scale has been used
and modifi ed to help assess everything from acute care by the
emergency medical technicians in the setting of trauma to long-term
assessment of the neurologically impaired patient in an ICU setting.
Naturally, the utility of the GCS scale has been examined for
outcome assessment in the SAH patient. Gotoh et al. ( 13 ) com-
pleted a prospective study that showed a very high correlation
between good GCS and good functional outcomes using the
Glasgow Outcome Scale (GOS) in SAH patients. Not surprisingly,
no clearly defi ned breakpoints existed between their groups of
patients and they tended to fall along a continuum from good to
bad outcomes. This fact is most likely by-product of small range
(fi ve) of potential outcomes using the GOS.

5. World
Federation
of Neurologic
Surgeons Grading
of SAH

Charles Drake in 1988 identifi ed the shortcomings of the grading
scales in coming usage at that time and helped to develop a
grading scale labeled the World Federation of Neurologic Surgeons
(WFNS) scale for SAH that utilized the ubiquitous GCS in combi-
nation with identifi cation of a focal defi cit ( 14 ). First, it was noted
that initial level of consciousness described by the GCS was predic-
tive of death and disability while the presence or the absence of
hemiplegia and aphasia added to the predictive value of the GCS
alone as the addition of these defi cits made rehabilitation diffi cult.
Condensing the GCS into a fi ve subdivisions and adding an axis
that accounted for the identifi cation of a focal defi cit provide the
scoring for the WFNS scale (Table 3 ).
The WFNS scale has been studied for predictive power with
some interesting results. It would appear, not surprisingly, that a
continuum exists toward worse outcome with increasing WFNS
score, however, clear distinctions between individual scores has not
been proven ( 10, 15 ). These breakpoints are important for prog-
nostication in order to show for example that a grade of WFNS 2
predicts a significant different outcome from WFNS grades of
1 and 3 ( 11 ). The WFNS is a very top heavy scale where the major-
ity of patients based on GCS will theoretically fall in the grades 0-3
while grades 4 and 5 encompass a GCS range of 3-12. Looking at
WFNS 4 as an example a GCS 12 without a focal defi cit would seem
to be quite different from a GCS 7 with hemiplegia which both
have the same WFNS score.