Basic discriminative and semantic processing in patients in the vegetative and minimally conscious state

Language-Related Brain Potentials in Patients With Disorders of Consciousness: A Follow-up Study to Detect “Covert” Language Disorders

“…This finding is in line with previous findings, and thus, it further indicates that ERPs can be a valuable tool for an early assessment of semantic language processing in DoCs. 18,19,21,22 Moreover, in our sample of DoC patients, the presence of N400 was also significantly related to the recovery of consciousness and functional communication according to CRS-R. In line with what was already found by Steppacher et al, 20 N400 presence could be indicative of a positive outcome for DoC patients-that is, consciousness recovery.…”

“…27,29 Auditory Semantic Paradigm A sentences task (implemented in and delivered by means of the Cubase Essential Software; Steinberg Media Technologies GmbH, 2008) was adopted. 18 It consisted of 100 sentences in which the last word was highly expected within the context and, thus, semantically congruent (eg, "the eel is a fish" or "a dress can be sewed") and 100 sentences in which the last word was semantically incongruent (eg, "the eel is a bird" or "a dress can be driven"). All correct end words also appeared as incorrect end words.…”

“…17 Currently, only few studies focusing on the characteristics of N400 and reporting evidence for a preserved semantic processing in DoC patients are available. [18][19][20][21][22] N400 paradigms were also included in hierarchical auditory batteries administered to investigate auditory processing in DoC patients as a whole (auditory, perceptual, semantic processing). 23 Among these studies, only 2 investigated the potential value of N400-ERP detection as a prognostic indicator of consciousness recovery in DoC patients.…”

Applied potential of task-free event-related paradigms for assessing neurocognitive functions in disorders of consciousness

“…The presence of an MMN indicates that a patient’s pre-attentive ability to detect a change in a sequence of sounds, which may be linked to auditory short-term memory, is preserved. Some studies have found that MMNs are more easily obtained and have larger amplitudes in patients in MCS than in patients with UWS ( Wijnen et al , 2007 ; Faugeras et al , 2012 ; Rossi Sebastiano et al , 2015 ), whereas other studies have found that the presence, amplitude, and latency of the MMN are unrelated to diagnosis ( Kotchoubey et al , 2005 ; Fischer et al , 2010 ; Risetti et al , 2013 ; Erlbeck et al , 2017 ). Possible explanations for such conflicting findings could be that the preservation of the automatic detection of stimulus change does not align perfectly with the UWS and MCS categories, or that the nature of the specific MMN stimuli employed in different studies, e.g.…”

“…Some studies have used the Arousal Facilitation Protocol of the Coma Recovery Scale-Revised, i.e. presenting deep pressure stimulation to different parts of the patient’s body to re-establish arousal if the patient appears to be getting drowsy ( Erlbeck et al , 2017 ), while other studies have monitored patients’ level of vigilance during recording by inspecting the EEG traces in real time, e.g. looking for sleep spindles or K complexes ( Fingelkurts et al , 2012 ; Risetti et al , 2013 ).…”