Recovery from prolonged disorders of consciousness:A dual-center prospective cohort study in China

BACKGROUND Recent innovations in intensive care have improved the prognosis of patients with severe brain injuries and brought more patients with disorders of consciousness(DoC).Data are lacking regarding the long-term outcomes of those patients in China.It is necessary to study the long-term outcomes of patients with prolonged DoC in light of many factors likely to influence crucial decisions about their care and their life.AIM To present the preliminary results of a DoC cohort.METHODS This was a two-center prospective cohort study of inpatients with vegetative state(VS)/unresponsive wakefulness syndrome(UWS).The study outcomes were the recovery from VS/UWS to minimally conscious state(MCS)and the long-term status of patients with prolonged DoC considered in VS/UWS or MCS for up to 6 years.The patients were evaluated using the Glasgow coma scale,coma recovery scale-revised,and Glasgow outcome scale.The endpoint of follow-up was recovery of full consciousness or death.The changes in the primary clinical outcome improvement in clinical diagnosis were evaluated at 12 mo compared with baseline.RESULTS The study population included 93 patients(62 VS/UWS and 31 MCS).The postinjury interval range was 28-634 d.Median follow-up was 20 mo(interquartile range,12-37 mo).At the endpoint,33 transitioned to an emergence from MCS or full consciousness,eight had a locked-in syndrome,and there were 35 patients remaining in a VS/UWS and 11 in an MCS.Seven(including one locked-in syndrome)patients(7.5%)died within 12 mo of injury.Compared with the unresponsive group(n=52)at 12 mo,the responsive group(n=41)had a higher proportion of males(87.8%vs 63.5%,P=0.008),shorter time from injury(median,40.0 d vs 65.5 d,P=0.006),higher frequency of vascular etiology(68.3%vs 38.5%,P=0.007),higher Glasgow coma scale score at admission(median,9 vs 6,P<0.001),higher coma recovery scale-revised score at admission(median,9 vs 2.5,P<0.001),at 1 mo(median,14 vs 5,P<0.001),and at 3 mo(median,20 vs 6,P<0.001),lower frequency of VS/UWS(36.6%vs 90.0%,P<0.001),and more favorable Glasgow outcome scale outcome(P<0.001).CONCLUSION Patients with severe DoC,despite having strong predictors of poor prognosis,might recover consciousness after a prolonged time of rehabilitation.An accurate initial diagnosis of patients with DoC is critical for predicting outcome and a long-term regular follow-up is also important.

Connecting the P300 to the diagnosis and prognosis of unconscious patients

The residual consciousness of unconscious patients can be detected by studying the P300, a wave among event-related potentials. Previous studies have applied tones, the subject＇s name and other names as stimuli. However, the results were not satisfactory. In this study, we changed the constituent order of subjects＇ two-character names to create derived names. The subject＇s derived names, together with tones and their own names, were used as auditory stimuli in event-related potential experiments. Healthy controls and unconscious patients were included in this study and made to listen to these auditory stimuli. In the two paradigms, a sine tone followed by the subject＇s own name and the subject＇s derived name followed by the subject＇s own name were used as standard and deviant stimuli, respectively. The results showed that all healthy controls had the P300 using both paradigms, and that the P300 in the second paradigm had a longer latency and two peaks. All minimally conscious state patients had the P300 in the first paradigm and the majority of them had the P300 in the second paradigm. Most vegetative state patients had no P300. Patients who showed the P300 in the two paradigms had more residual consciousness, and patients with the two-peak P300 had a higher probability of awakening within a short time. Our experimental findings suggest that the P300 event-related potential could reflect the conscious state of unconscious patients.