The Glasgow Coma Scale (GCS) and the Swedish Reaction Level Scale (RLS
85), two level-of-consciousness scales used in the assessment of patie
nts with head injury, were compared in a prospective study of 239 pati
ents admitted to a regional head injury unit over a 4-month period. As
sessments were made by nine staff members ranging from house officer t
o registrar, after briefing about the two scales. Data were also colle
cted on age, nature of injuries, surgical treatment, and condition at
discharge or transfer using the Glasgow Outcome Scale. Both the GCS an
d the RLS85 reliably identified comatose patients and those with minor
head injury, but were much less effective in defining the response le
vel in patients considered to have a moderate head injury. Only 41% of
the patients allocated to a moderate-head-injury category by the GCS
and the RLS85 were common to both groups. Where a mismatch occurred, n
either scale allocated patients to a 'better' or 'worse' category more
frequently than the other. Assessment of patients' conscious levels u
sing the GCS was difficult in only two cases. One patient had facial i
njuries, and the other was intubated. The RLS85 was reported by all us
ers to be simpler to use than the GCS, but the latter is much more wid
espread in use. Both scales function well in cases of severe and minor
head injury, but have weaknesses when defining moderate head injury.
Level-of-consciousness scales are only an aid to assessment and the fi
nal choice between the two scales must remain a matter of personal or
departmental preference.