Cognitive Event-Related Potentials during the Sub-Acute Phase of Severe Traumatic Brain Injury and Their Relationship to Outcome

Patients With Better Outcome Have Higher ERP Response to Emotional Auditory Stimuli

PURPOSE

Accuracy of outcome prognosis is one of the most important tasks of coma arousal therapy. Reactions toward sensory stimuli are the most significant predictor of conscience and cognitive functions restoration after a brain injury. A paradigm that includes ERP registration has the advantage of detailed stimuli processing visualization. The authors aimed to investigate perception and distinguishing of emotionally significant sounds (crying and laughter) in coma patients with different consciousness restoration prognosis.

METHODS

EEG was recorded in 24 comatose patients with different outcomes (scored with Glasgow Outcome Scale-Extended) and 32 healthy volunteers. The authors presented sounds of crying and laughter. ERPs for sound stimulation were calculated.

RESULTS

An analysis of the correlation of ERP components and Glasgow Outcome Scale-Extended score was performed. P200 (r = 0.6, P = 0.0014) and N200 amplitudes (r = -0.56, P = 0.0037) for emotional sounds correlated with the Glasgow Outcome Scale-Extended score. The significant differences of P300 and N400 amplitudes corresponded to differences of response between sounds of crying and laughter in subjects of the control group. Unlike the control group, comatose participants with good outcome produced similar electrical activity toward pleasant and unpleasant emotional stimuli.

CONCLUSIONS

Comatose patients with good outcome produced more prominent ERP for emotional sounds. Even the good outcome participants were unable to distinguish emotional sounds of different moods, which indicate the preservation of solely robust mechanisms of sound processing. N200 and P200 amplitudes for emotional stimuli correlated significantly with outcome prognosis in coma patients.

Virtual Reality Based Cognitive Rehabilitation in Minimally Conscious State: A Case Report with EEG Findings and Systematic Literature Review

Chronic disorders of consciousness cause a total or partial and fluctuating unawareness of the surrounding environment. Virtual reality (VR) can be useful as a diagnostic and/or a neurorehabilitation tool, and its effects can be monitored by means of both clinical and electroencephalography (EEG) data recording of brain activity. We reported on the case of a 17-year-old patient with a disorder of consciousness (DoC) who was provided with VR training to improve her cognitive-behavioral outcomes, which were assessed using clinical scales (the Coma Recovery Scale-Revised, the Disability Rating Scale, and the Rancho Los Amigos Levels of Cognitive Functioning), as well as EEG recording, during VR training sessions. At the end of the training, significant improvements in both clinical and neurophysiological outcomes were achieved. Then, we carried out a systematic review of the literature to investigate the role of EEG and VR in the management of patients with DoC. A search on PubMed, Web of Science, Scopus, and Google Scholar databases was performed, using the keywords: "disorders of consciousness" and "virtual reality", or "EEG". The results of the literature review suggest that neurophysiological data in combination with VR could be useful in evaluating the reactions induced by different paradigms in DoC patients, helping in the differential diagnosis. In conclusion, the EEG plus VR approach used with our patient could be promising to define the most appropriate stimulation protocol, so as to promote a better personalization of the rehabilitation program. However, further clinical trials, as well as meta-analysis of the literature, are needed to be affirmative on the role of VR in patients with DoC.