Event-related brain potential modulation in patients with severe brain damage

Finding a way in: A review and practical evaluation of fMRI and EEG for detection and assessment in disorders of consciousness

“…Perrinet al (2006) observed a P300 response in all members of a sample of LIS (N = 4) and MCS (N = 6) patients and in 60% of VS patients (N = 5). Other studies lie in between these two extremes: Kotchoubey and colleagues consistently report a P300 in about 30% of their VS and MCS patients (Kotchoubey, 2005, 50 VS patients;Kotchoubey et al, 2005, 50 VS patients and 38 MCS patients), with no differences between the two groups ; Cavinato et al (2011) observed P3 in all of their 6 MCS patients, and 6/11 VS patients. The variability in these results is attributable to many of the same factors as variability in fMRI results among patients with DOC, such as aetiology, diagnostic criteria, level of arousal-but also to the type of stimuli used to elicit the P3.…”

Neuroimaging and Outcome Assessment in Vegetative and Minimally Conscious State

“…This finding is in line with several studies that have confirmed the utility of P300 evoked by deviant tones to predict awakening and favourable outcome from coma and VS (Cavinato et al, 2009). In another study Cavinato et al, (2011) continue to using the "subject's own name" paradigm, but add a pure tone and an "other first name" paradigm. The authors instructed their patients to count the occurrence of deviant stimuli to better differentiate between patients in VS and MCS.…”

30. Vegetative versus minimally conscious states: A study using TMS-EEG, sensory and event-related potentials

“…The significant time-windows (i.e., EEG signal exceeding three times the standard deviation of the pre-stimulus activity for at least 20 ms) are separately indicated for the ipsilateral electrode with a horizontal red line and for the electrodes contralateral to the TMS hot-spot with a black line. doi:10.1371/journal.pone.0057069.g001 [6,11,13,37]. EEG activity was continuously recorded (bandpass filtered at 0.1-100 Hz; digitised at a sampling rate of 1024 Hz) from 19 scalp electrodes mounted on an elastic cap (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) International System) all referred to linked earlobes, and the ground electrode was positioned on Fpz.…”

“…Neuroimaging methods (e.g., positron emission tomography -PET, and functional magnetic resonance imaging -fMRI) and electrophysiological techniques (e.g., electroencephalography -EEG, magnetoencephalography -MEG, and event-related potentials -ERPs) have revealed neocortical activation in several VS cases [5][6][7][8][9][10][11][12][13][14], suggesting the possibility of a partial preservation of cognitive processing, such as traces of speech comprehension and preserved motor imagery of complex tasks. Moreover, recent advances in structural MRI techniques, such as diffusion tensor imaging (DTI), which can determine the integrity of white matter tracts in vivo, have revealed the widespread damage of brain fibre tracts in VS patients [15].…”

“…For example, the bilateral absence of median-nerve cortical SEPs is associated with no recovery in almost 100% of patients. ERPs (mainly the mismatch negativity and the P300 component) have been used extensively to detect the electrophysiological correlates of cognitive functions, potentially reflecting some level of awareness in VS and MCS patients [6,10,11,13,[37][38][39]. The presence of ERPs has suggested some level of residual cognitive processing in a minority of VS and MCS patients, and ERPs are now recognised as valuable research techniques for diagnostic and prognostic purposes [40].…”