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.

Clinical application of Chinese Nanjing persistent vegetative state scale

Background:It is a challenge to characterize the consciousness level of patients with severe disturbance of consciousness and predict their prognosis effectively for Chinese doctors.We aimed to investigate the psychometric property and the diagnostic practicality of severe disturbance of consciousness by Chinese Nanjing persistent vegetative state scale(CNPVSS)which was first set up in 1996 and modified in 2001 and 2011.Methods:The concurrent validity,inter-rater consistency and diagnostic accuracy of CNPVSS and Chinese version of coma recovery scale-revised(CRS-R)were investigated by assessment of 380 patients with severe disorders of consciousness.Results:Total scores of the CNPVSS were correlated significantly with that of the CRS-R,indicating acceptable concurrent validity.Sub-scale analysis showed moderate to high inter-rater reliability and test-retest reliability.CNPVSS was superior to CRS-R on the diagnosis sensitivity.The CNPVSS was able to distinguish 65 patients in emergence from minimal consciousness state who were misclassified as in minimal consciousness state(MCS)by the CRS-R,and it could also distinguish two patients in MCS who were misclassified as in vegetative state by the CRS-R.Conclusion:The CNPVSS is an appropriate measurement and is sensitive to distinguish the MCS patients from the VS patients.