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Detection and Interpretation of Impossible and Improbable Coma Recovery Scale-Revised Scores

Published:March 01, 2016DOI:https://doi.org/10.1016/j.apmr.2016.02.009

      Abstract

      Objective

      To determine the frequency with which specific Coma Recovery Scale-Revised (CRS-R) subscale scores co-occur as a means of providing clinicians and researchers with an empirical method of assessing CRS-R data quality.

      Design

      We retrospectively analyzed CRS-R subscale scores in hospital inpatients diagnosed with disorders of consciousness (DOCs) to identify impossible and improbable subscore combinations as a means of detecting inaccurate and unusual scores. Impossible subscore combinations were based on violations of CRS-R scoring guidelines. To determine improbable subscore combinations, we relied on the Mahalanobis distance, which detects outliers within a distribution of scores. Subscore pairs that were not observed at all in the database (ie, frequency of occurrence=0%) were also considered improbable.

      Setting

      Specialized DOC program and university hospital.

      Participants

      Patients diagnosed with DOCs (N=1190; coma: n=76, vegetative state: n=464, minimally conscious state: n=586, emerged from minimally conscious state: n=64; 794 men; mean age, 43±20y; traumatic etiology: n=747; time postinjury, 162±568d).

      Interventions

      Not applicable.

      Main Outcome Measure

      Impossible and improbable CRS-R subscore combinations.

      Results

      Of the 1190 CRS-R profiles analyzed, 4.7% were excluded because they met scoring criteria for impossible co-occurrence. Among the 1137 remaining profiles, 12.2% (41/336) of possible subscore combinations were classified as improbable.

      Conclusions

      Clinicians and researchers should take steps to ensure the accuracy of CRS-R scores. To minimize the risk of diagnostic error and erroneous research findings, we have identified 9 impossible and 36 improbable CRS-R subscore combinations. The presence of any one of these subscore combinations should trigger additional data quality review.

      Keywords

      List of abbreviations:

      CRS-R (Coma Recovery Scale-Revised), DOC (disorder of consciousness), EMCS (emerged from minimally conscious state), MCS (minimally conscious state), VS (vegetative state)
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      Linked Article

      • Correction
        Archives of Physical Medicine and RehabilitationVol. 99Issue 12
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          In the article by Chatelle et al, Detection and Interpretation of Impossible and Improbable Coma Recovery Scale-Revised Scores, published in Archives of Physical Medicine and Rehabilitation 2016;97:1295-300 ( 10.1016/j.apmr.2016.02.009 ), Appendix 1 reports subscore combinations that are “impossible” to obtain if CRS-R administration and guidelines are followed properly. However, the authors have determined that these subscore combinations do not violate CRS-R administration or scoring rules. Consequently, the authors have re-analyzed all subscale scores, including the nine subscore combinations previously listed as “impossible,” using the methods described in the article.
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