Clinimetric study and review of the Reaction Level Scale

Although the Reaction Level Scale (RLS) is still used for the assessment of the level of consciousness in distinct centers, its clinical characteristics and significance have been incompletely researched. In the current study, the clinimetric properties, the prognostic value, and the impact of the raters' background on the application of the RLS, in comparison with the Glasgow Coma Scale (GCS), are investigated.

A systematic review on the available clinical evidence for the RLS was first carried out. Next, the RLS was translated into Greek, and patients with neurosurgical pathologies in need of consciousness monitoring were independently assessed with both RLS and GCS, by four raters (two consultants, one resident, and one nurse) within one hour. Interrater reliability, construct validity, and predictive value (mortality and poor outcome, at discharge and at 6 months) were evaluated.

Literature review retrieved 9 clinimetric studies related to the RLS, most of low quality, indicating that the scale has not been thoroughly studied. Both versions of the RLS (original and modified) showed high interrater reliability (κ_w >0.80 for all pairs of raters), construct validity (Spearman's p > .90 for all raters), and prognostic value (areas under the curve >0.85 for all raters and outcomes). However, except for broader patients' coverage, it failed to show any advantage over the GCS.

The RLS has not succeeded in showing any advantage over the GCS in terms of reliability and validity. Available evidence cannot justify its use in clinical practice as a substitute to the widely applied GCS.