Article

Mismatch negativity to patient's own name in chronic disorder of consciousness

Laboratory for Higher Brain Functions, Institute of Psychology, Chinese Academy of Sciences, 4A Datun Road, Chaoyang District, Beijing 100101, China.
Neuroscience Letters (Impact Factor: 2.03). 10/2008; 448(1):24-8. DOI: 10.1016/j.neulet.2008.10.029
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ABSTRACT

Previous studies implicated potential value of mismatch negativity (MMN) in predicting recovery of consciousness in patients with disorders of consciousness (DOC). We have adopted a novel MMN evoked by subject's own name (SON), a self-referential stimulus thought to be powerful in evoking residual brain activity, and examined the correlation between the MMN and recovery of consciousness in patients with chronic (>1 month) DOC. Twelve patients and 12 age-matched healthy controls were investigated. The patients were diagnosed as coma (n=4), vegetative state (VS, n=6), and minimally conscious state (MCS, n=2), mainly based on the JFK Coma Recovery Scale-Revised. The SON-evoked MMN (SON-MMN) was present in seven patients. Critically, the presence of SON-MMN was significantly correlated with recovery of consciousness. While four of the five patients (three VS and two coma) showing SON-MMN changed to MCS 3 months later, the rest of the patients (three VS and two coma) without SON-MMN failed to show any clinical improvement. Our study thus illustrates that the subject's own name is effective in evoking MMN in patients with DOC, and that SON-MMN has potential prognostic values in predicting recovery of consciousness.

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    • "Tonotopic studies on the N100 suggest that this wave may be generated from tonotopic but also from non tonotopic areas[18]. This may explain this distinction between a response and a frequency organization of the AC and why no correlation was found between the presence of a N100 and the transition from coma/UWS to MCS[19]. Future investigations taking into account the frequency encoding are necessary to reveal whether this could improve the prognosis of these patients. "
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    ABSTRACT: To measure the level of residual cognitive function in patients with disorders of consciousness, the use of electrophysiological and neuroimaging protocols of increasing complexity is recommended. This work presents an EEG-based method capable of assessing at an individual level the integrity of the auditory cortex at the bedside of patients and can be seen as the first cortical stage of this hierarchical approach. The method is based on two features: first, the possibility of automatically detecting the presence of a N100 wave and second, in showing evidence of frequency processing in the auditory cortex with a machine learning based classification of the EEG signals associated with different frequencies and auditory stimulation modalities. In the control group of twelve healthy volunteers, cortical frequency processing was clearly demonstrated. EEG recordings from two patients with disorders of consciousness showed evidence of partially preserved cortical processing in the first patient and none in the second patient. From these results, it appears that the classification method presented here reliably detects signal differences in the encoding of frequencies and is a useful tool in the evaluation of the integrity of the auditory cortex. Even though the classification method presented in this work was designed for patients with disorders of consciousness, it can also be applied to other pathological populations.
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    • "A full P300 response consists of two underlying components (P3a and P3b), which are thought to reflect attention switching and subsequent context updating (Polich, 2007). Memory: Several groups have utilized name stimuli in an oddball paradigm to evoke responses indicative of own name recognition in brain-injured patients (Cavinato et al., 2011; Fischer et al., 2008, 2010; Marosi et al., 1993; Mazzini et al., 2001; Perrin et al., 2006; Qin et al., 2008; Schnakers et al., 2008). When the subject's own name is presented with low probability in a sequence of unfamiliar names, recognition of one's own name is associated with a P300 (Perrin et al., 1999, 2006). "
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    Full-text · Article · Apr 2015 · Journal of Neuroscience Methods
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    • "Another line of research has studied neural response to sensory stimulation in DOC patients. The presence of a mismatch-negativity EEG component, indicating neural detection of deviant stimuli, has been demonstrated in DOC patients and shown to coincide with the return of functional communication (Kane et al. 1993; Fischer et al. 1999, 2010; Kotchoubey et al. 2003; Wijnen et al. 2007; Qin et al. 2008). The P300 EEG component, elicited to infrequent stimuli as well as stimuli relevant to a particular participant or task, has likewise been demonstrated in DOC populations and often tracks patient recovery (Kotchoubey et al. 2001; Cavinato et al. 2009; Faugeras et al. 2012). "
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