Autonomic responsivity and semantic associative competences in disturb of consciousness

Linguistic associative functions in disorders of consciousness patient (DOC) were studied in the present research by using autonomic measures (Skin Conductance Response, SCR; Heart Rate, HR). We intended to verify the preservation of semantic linguistic processes in Vegetative State (VS) and Minimal Consciousness State (MCS) by considering arousal modulation. Twenty-four patients and twenty controls were submitted to an auditory semantic task (congruous or incongruous word sequences). A similar increased SCR/HR was found for both DOC and control group in response to incongruous condition. This modulation was interpreted as a marker of the increased cognitive difficulty in processing and restoring incongruent information. However, MCS and VS groups quantitatively (but not qualitatively) differed in term of degree of increased arousal, since higher SCR and HR increasing was observed for MCS than VS. These results were interpreted as a marker that the semantic processing was partially preserved in both VS and MCS patients.

Cross-modal perception (face and voice) in emotions. ERPs and behavioural measures

Emotion decoding constitutes a case of multimodal processing of cues from multiple channels. Previous behavioural and neuropsychological studies indicated that, when we have to decode emotions on the basis of multiple perceptive information, a cross-modal integration has place. The present study investigates the simultaneous processing of emotional tone of voice and emotional facial expression by event-related potentials (ERPs), through an ample range of different emotions (happiness, sadness, fear, anger, surprise, and disgust). Auditory emotional stimuli (a neutral word pronounced in an affective tone) and visual patterns (emotional facial expressions) were matched in congruous (the same emotion in face and voice) and incongruous (different emotions) pairs. Subjects (N=30) were required to process the stimuli and to indicate their comprehension (by stimpad). ERPs variations and behavioural data (response time, RTs) were submitted to repeated measures analysis of variance (ANOVA). We considered two time intervals (150-250; 250-350 ms post-stimulus), in order to explore the ERP variations. ANOVA showed two different ERP effects, a negative deflection (N2), more anterior-distributed (Fz), and a positive deflection (P2), more posterior-distributed, with different cognitive functions. In the first case N2 may be considered a marker of the emotional content (sensitive to type of emotion), whereas P2 may represent a cross-modal integration marker, it being varied as a function of the congruous/incongruous condition, showing a higher peak for congruous stimuli than incongruous stimuli. Finally, a RT reduction was found for some emotion types for congruous condition (i.e. sadness) and an inverted effect for other emotions (i.e. fear, anger, and surprise).