The main objective of this study was to investigate the misdiagnosis rates of clinical consensus compared to those of repeated behavior-scale assessments. After the single CRS-R behavior evaluation, it was found that the proportion of misdiagnosis of clinical MCS was 24.7%, while the repeated CRS-R evaluation results showed that the proportion of misdiagnosis of clinical MCS was 38.2%. A total of 16.7% of EMCS patients was misdiagnosed with MCS, and 1.1% of EMCS patients was misdiagnosed with UWS.
For the evaluation of the consciousness level of patients with prolonged DOC, many previous studies had compared the diagnostic results of the standard CRS-R scale with other scales, and it was been found that the CRS-R scale had the highest sensitivity in detecting the consciousness of patients with MCS [35, 36]. When the CRS-R scale was used, it was found that many patients with a clinical-consensus diagnosis of unconscious actually remained minimally conscious. Schnakers et al. found that 41% of patients with a clinical-consensus diagnosis of UWS was actually found to suffer from MCS after an evaluation using the standard CRS-R behavior scale, whereas the clinical consensus was that 10% of patients with MCS were actually higher conscious EMCS (fully conscious) . A recent study on repeated CRS-R behavior assessments showed that the clinical consensus still had a 33% misdiagnosis rate when diagnosing MCS patients . This also supports the results of the current study. It was found that repeated behavioral assessments could identify 38.2% MCS patients. Moreover, the proportion of misdiagnosis of EMCS with full consciousness was 16.7%. When the evaluation results of the single CRS-R scale were compared with the clinical consensus, it was found that 24.7% of patients were misdiagnosed with MCS by clinical consensus, which was significantly lower than the 41% found in previous studies on the proportion of misdiagnosis; however, the 14.6% misdiagnosis rate of EMCS was similar to the 10% rate in a previous study . With the continuous progress in the field of prolonged DOC, clinicians have gained a deeper understanding of this concept. This may be the reason for the significant difference in misdiagnosis rates over the past 10 years. In addition, the difference between the results of single assessments and repeated assessments emphasizes that the fluctuations of patients’ responsiveness have an effect on neuro-behavioral assessments, and also emphasizes the importance of repeated assessments in clinical diagnosis.
The degree to which the patient’s demographic factors lead to clinical misdiagnosis was analyzed, and it was found that differences in gender, etiology, age groups and postinjury time were not factors in clinical-consensus misdiagnosis. It is highly likely that clinical workers are highly dependent on the patients’ bedside behaviors in the patients’ daily management and may not be using systematic and standardized behavioral-assessment tools to diagnose awareness. In addition, it was found that the Glasgow Coma Scale (GCS) was widely used for almost all patients admitted to the hospital, while a previous study showed that that scale was not appropriate for assessing a patient’s level of consciousness . Unlike the GCS scale, the CRS-R scale has very clear MCS diagnostic criteria, and the evaluation of consciousness from various angles can be used to more sensitively diagnose the consciousness level of patients, which greatly reduces the misdiagnosis of patients with prolonged DOC. Therefore, the use of standardized CRS-R assessment tools is particularly important for the detection of clinical patients’ level of consciousness and patient management.
During the implementation of the standardized CRS-R scale, many studies found that the standard CRS-R scale still lead to some misdiagnoses. Cheng and Gosseries et al. found that the patient’s name was more suitable stimulus for the detection of auditory localization than other sound stimuli . Vanhaudenhuys et al. also found that the best way to check visual pursuit in MCS patients was to use a moving mirror rather than a moving person or object [38, 39]. Therefore, the application of personally related visual and auditory stimulation can better reduce the proportion of misdiagnosis of patients compared with natural stimulation . In addition, when the CRS-R was used to evaluate the use of functional objects for MCS patients, the use of personalized objects more frequently elicited responses from patients, thereby identifying misdiagnosed EMCS . For this study, repeated CRS-R behavior assessments were employed, during which family members or caregivers were asked about patients’ items of interest. To better elicit the patients’ responses, a variety of different stimuli were selected according to the patients’ performance during the evaluation process, namely natural stimuli and personally related stimuli. It was found that when patients were diagnosed with MCS based on the first behavior evaluation, most showed signs of consciousness on the visual (72.7%) and motor (54.5%) subscales, and few showed signs of consciousness on the auditory (9.1%) and communication (4.5%) subscales. After repeated evaluations, 10 patients showed signs of consciousness on the visual subscale, 4 patients on the motor subscale, and 2 patients in the auditory subscale. This was most likely due to fluctuations in the patients’ levels of arousal or consciousness and due to the use of personally associated stimuli.
It was also found that, for the vast majority of patients diagnosed with MCS, the items eliciting signs of consciousness were mainly related to the visual subscale (visual pursuit and visual fixation), the motor subscale (automatic motor response and localization to noxious stimulation), and the auditory subscale (reproducible movement to command). These results were confirmed by a previous study , but with the difference that the most sensitive item in the present study was the visual subscale, while the most sensitive item in the previous study was the reproducible movement to command items on the auditory subscale.
Based on these results, it was found that the clinical consensus had a higher proportion of misdiagnosis, especially compared to repeated CRS-R scales. This highlights the importance of the CRS-R scale in the assessment of patient consciousness. It is suggested that, for patient daily management, clinicians should at least evaluate visual pursuit and visual fixation for the visual subscale, automatic motor response and localization to noxious stimulation for the motor subscale, and reproducible movement to command for the auditory subscale when assessing patients’ levels of consciousness. This can greatly reduce misdiagnosis, although, for patients with prolonged DOC, bedside neurobehavioral assessment has some limitations, and neuroimaging is an important method for the diagnosis of consciousness ; however, a behavioral assessment is still the most direct and portable method and should be promoted in clinical practice.
The limitation of this study was that no neuroimaging methods were used to evaluate the enrolled patients with prolonged DOC. Because the CRS-R scale still produces some false negatives, in the future, behavioral assessments combined with neuroimaging should be used to truly understand misdiagnosis by clinical consensus.