Validation of the SECONDs: a new short scale to assess disorders of consciousness

Introduction: Clinical examination of severely brain-injured patients with disorders of consciousness (DoC) requires repeated standardized assessments to provide an accurate diagnosis. However, the administration time of the current gold-standard Coma Recovery Scale-Revised (CRS-R) limits its use in clinical routine. We here propose and validate a faster tool to assess consciousness.

Methods: The Simplified Evaluation of CONsciousness Disorders (SECONDs) is based on six mandatory items (observation, response to command, visual fixation, visual pursuit, oriented behaviours, arousal) and two conditional items (localisation to pain, communication) (Figure 1). Fifty-seven DoC patients were assessed four times on two consecutive days: one CRS-R and one SECONDs were administered on one day, whereas two SECONDs were administered on the other day (Figure 2). The three examiners remained blind to diagnosis and medical history of the patients. Concurrent validity and inter-/intra-rater reliability were computed using weighted kappa coefficients, while administration times for the SECONDs vs. the CRS-R were compared with a Mann-Whitney U test.

Results: “Substantial” and “almost perfect” agreements (kappas: 0.78-0.85) were found comparing the CRS-R against the same-day SECONDs or against the highest-scoring SECONDs. Intra- and inter-rater reliabilities showed “almost perfect” agreements (kappas: 0.85-0.91 and 0.82-0.85 respectively) (Figure 3). Administration time was significantly shorter for the SECONDs than for the CRS-R (7 vs. 17 min, p<0.001).

Conclusion: The SECONDs is a fast and valid clinical scale to evaluate patients with DoC. This new tool offers an alternative to existing scales, well-suited for clinicians with major time constraints, and can be easily repeated to provide an accurate diagnosis.