Estimating the Minimal Number of Repeated Examinations for Random Responsiveness With the Coma Recovery Scale—Revised as an Example

Abstract

Objective: The aim of this study was to develop a general method to estimate the minimal number of repeated examinations needed to detect patients with random responsiveness, given a limited rate of missed diagnosis.Methods: Basic statistical theory was applied to develop the method. As an application, 100 patients with disorders of consciousness (DOC) were assessed with the Coma Recovery Scale–Revised (CRS-R). DOC patients were supposed to be examined for 13 times over 20 days, while anyone who was diagnosed as a minimally conscious state (MCS) in a round would no longer be examined in the subsequent rounds. To test the validation of this method, a series of the stochastic simulation was completed by computer software under all the conditions of possible combinations of three kinds of distributions for p, five values of p, and four sizes of the sample and repeated for 100 times.Results: A series of formula was developed to estimate the probability of a positive response to a single examination given by a patient and the minimal number of successive examinations needed based on the numbers of patients detected in the first i (i =1, 2,.) rounds of repeated examinations. As applied to the DOC patients assessed with the CRS-R, with a rate of missed diagnosis < 0.0001, the estimate of the minimal number of examinations was six in traumatic brain injury patients and five in non-traumatic brain injury patients. The outcome of the simulation showed that this method performed well under various conditions possibly occurring in practice.Interpretation: The method developed in this paper holds in theory and works well in application and stochastic simulation. It could be applied to any other kind of examinations for random responsiveness, not limited to CRS-R for detecting MCS; this should be validated in further research.

Clinical application of recommendations for neurobehavioral assessment in disorders of consciousness: an interdisciplinary approach

“…Collective evidence evaluating the utility of the CRS-R, compared to other behavior rating scales, diagnostic modalities, and neurophysiological studies, demonstrates the superiority of the CRS-R as a sensitive and reliable tool to accurately identify and discriminate among the levels of DoC ( Lechinger et al, 2013 ; Annen et al, 2019 ; Formisano et al, 2019a ; da Conceição Teixeira et al, 2021 ). Additional evidence focusing on the utility of the CRS-R identifies the benefit of serial use of the CRS-R to improve accuracy of identifying behavioral presentation of DoC ( Wannez et al, 2017 ; Yang et al, 2021 ). Further evaluation and investigation of the CRS-R has produced development of a CRS-R index to improve total score interpretation and translation of the CRS-R into multiple languages for international use ( Lombardi et al, 2007 ; Tamashiro et al, 2014 ; Binder et al, 2018 ; Annen et al, 2019 ; Zhang et al, 2019 ).…”

“…Based on these results, the authors recommend performing at least five assessments within a short time interval (e.g., 2 weeks) to boost diagnostic certainty, even in persons with chronic DoC ( Wannez et al, 2017 ). A similar study by Yang et al (2021) developed statistical formulas to estimate the probability of positive response with use of the CRS-R in relation to the minimal number of successive examinations. Yang et al (2021) identified that a minimum of five assessments is needed for patients with non-traumatic DoC and six assessments for traumatic DoC ( Yang et al, 2021 ).…”

“…A similar study by Yang et al (2021) developed statistical formulas to estimate the probability of positive response with use of the CRS-R in relation to the minimal number of successive examinations. Yang et al (2021) identified that a minimum of five assessments is needed for patients with non-traumatic DoC and six assessments for traumatic DoC ( Yang et al, 2021 ).…”

Classifying Disorders of Consciousness: Past, Present, and Future

“…15 Instead, five or more assessments repeated over several days may be necessary to appropriately evaluate the level of consciousness in patients with prolonged disorders of consciousness (36% misdiagnosis with a single assessment vs. 5% with five assessments). 69 70…”

“…15 Instead, five or more assessments repeated over several days may be necessary to appropriately evaluate the level of consciousness in patients with prolonged disorders of consciousness (36% misdiagnosis with a single assessment vs. 5% with five assessments). 69,70 The MCS is frequently a transitional state, as patients who were previously comatose or VS/UWS improve to MCS during their recovery trajectory. A transition from MCS to a higher plane of consciousness or better is signaled when patients demonstrate reliable functional communication, or the ability to use two different objects appropriately, or both; such patients are designated as "emerged from MCS" (eMCS).…”