Responsiveness, Minimal Detectable Change, and Minimally Clinically Important Differences for the Disorders of Consciousness Scale.

ABSTRACT

OBJECTIVES: To determine the responsiveness, minimal detectable change (MDC95), and minimally clinically important difference (MCID) of the Disorders of Consciousness Scale (DOCS-25) in patients with severe traumatic brain injury (TBI) and to report the percentages of patients' change scores exceeding MDC and MCID after 3 weeks of inpatient rehabilitation. SETTING: Post-acute rehabilitation hospitals. PARTICIPANTS: One hundred seventy-two patients with severe TBI. Ninety-two were included in the DOCS-25 3-week analysis. DESIGN: Retrospective cohort study. MAIN MEASURE(S) Disorders of Consciousness Scale, Glasgow Coma Scale. RESULTS: The effect size and standardized response mean of the DOCS-25 for those who improved were 0.45 and 1.3, respectively-moderate to large by Cohen criteria. The MDC95 (95% confidence interval) was 5.6. Distribution-based MCIDs for small (0.20 SD), moderate (0.33 SD), and large (0.50 SD) differences were 2.6 units, 4.4 units, and 6.6 units, respectively. The anchor-based MCID was 8.6 units. On average, patients who improved (n = 57) gained 14.5 units by week 3, exceeding the anchor-based MCID. On average, patients who did not improve (n = 35) declined by 7.2 units, which exceeds both the MDC95 and the largest distribution-based MCID. CONCLUSION(S) The DOCS-25 is a responsive, clinician-observed assessment tool for capturing change in neurobehavioral function in adults recovering from severe TBI. This is the first study to provide evidence for the size of neurobehavioral function change that might indicate meaningful recovery in patients with severe TBI. Results from this study may support future research by better informing sample size calculations for clinical trials and also assist clinicians in identifying when variation in level of consciousness is consequential enough to warrant changes in intervention.