Electrophysiological Correlates of Emotional and Crossmodal Stimuli Processing Among Alcohol-dependent Participants
Condition: Alcohol-dependence
MeSH terms: Alcoholism
Study type: Observational

Summary: 
      Alcohol-dependence is the most widespread addiction in Western countries and leads to a wide
      range of impairments at cerebral and cognitive levels. It has also been showed that
      alcohol-dependence is associated with emotional disturbances, particularly for the decoding
      of emotional facial expressions (EFE). In view of the crucial role played by EFE to develop
      and maintain satisfactory interpersonal relations, this emotional processing impairment may
      have deleterious consequences on alcohol-dependent patient's social well-being, and this
      deficit is thus of particular clinical interest. Nevertheless, this deficit has up to now
      been evaluated only by means of experiments using paradigms with low ecological value (i.e.
      presentation of EFE in isolation and in the central vision field), while in the real life,
      emotional stimuli are most frequently appearing together with other emotional stimulations
      (particularly voices) and in the peripheral vision field. Moreover, the cerebral correlates
      of this emotional deficit are still to be determined.

      The present study thus aims at exploring the Emotional Facial Expressions (EFE) decoding in
      alcoholism using a more ecological paradigm, based on peripheral presentation of emotional
      crossmodal stimuli (i.e. the simultaneous presentation of emotionally congruent face and
      voice).

      Main aim: Determining the electrophysiological characteristics (latencies and amplitudes) of
      the event-related components elicited among recently detoxified alcohol-dependent
      participants, while performing an emotion-detection task on crossmodal stimuli (voices and/or
      faces) presented centrally or peripherally, and comparing these characteristics with those
      obtained among paired healthy participants.

      Secondary objectives:

        -  Exploring the electrophysiological pattern modifications among alcohol-dependent
           participants for the emotional faces and voices decoding (unimodal conditions), using
           spatio-temporal analyses methods.

        -  Exploring the electrophysiological waves associated with peripheral crossmodal stimuli
           processing among healthy participants.

        -  Exploring the behavioral correlates (reaction times and accuracy) of the
           emotion-detection task among alcohol-dependent participants while processing peripheral
           stimuli.

        -  Exploring the psychopathological comorbidities among alcohol-dependent participants and
           their influence on the behavioral and electrophysiological results.
    

Detailed description: 
      Methodology: Evaluation the event-related potentials elicited among alcohol-dependent and
      healthy participants while performing an emotion-detection task on unimodal (visual or
      auditory) or crossmodal (visuo-auditory) stimulations presented centrally or peripherally.
      Event-related potentials allow to monitor the electrical activity of the brain with high
      temporal resolution and to detect even minor neurocognitive restrictions. This cerebral
      measures will be completed by behavioral (reaction times and accuracy) and psychopathological
      measures.

      No specific interventions assigned to the subjects of the study.

      Evaluations: The room contains a panoramic screen (2.4 X 4 meters) covering a 180 degrees of
      visual angle. Participants will seat in a chair situated two meters away from the screen, in
      front of a table on which the response pad will be placed. Three projectors will display the
      visual stimulations, either centrally or lateralized (-12°, -24°on the left or +12°, +24° on
      the right). Headphones will be placed on participants' ears in order to display the auditory
      stimulations, either on both ears or lateralized (left or right ear), and presented
      separately (unimodal conditions) or simultaneously (crossmodal condition) with the visual
      stimuli. Visual stimuli, constructed using FaceGen 3.4 program, will be emotional faces (two
      males, two females) depicting happiness, anger or a neutral expression. Auditory stimuli (two
      males, two females), from a validated battery, will be emotional voices depicting happiness,
      anger or a neutral prosody and presented at a 70 decibels level. Crossmodal stimulations will
      be a combination of visual and auditory stimuli, congruent for gender and emotion. Experiment
      will be composed of 39 conditions: 3 stimulations (visual, auditory, visuo-auditory) X 3
      emotions (anger, happiness, neutral) X 3/5 lateralisation (-24°, -12°, 0°, 12°, 24°). Each
      condition will be evaluated on the basis of 50 stimulations. Event-related potentials will be
      recorded during the whole experiment by means of a 128 electrodes cap placed on participant's
      head and connected with an amplifier (Advanced Neuro Technology, ANT) and a recording
      computer, synchronised with the stimulation system. Behavioral responses will be recorded by
      means of a response pad. Psychopathological measures will be conducted using validated
      questionnaires: State and trait anxiety (STAI A and B, Spielberger et al., 1983), depression
      (BDI, Beck et al., 1987), interpersonal problems (Horowitz et al. (1988)), evaluating the
      quantity and quality of the social interactions, and the integration in the family and
      relationship background and alexithymia (Bagby et al., 1994).
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        -  22 recently detoxified participants, diagnosed as alcohol-dependent on the basis of
             DSM-IV criteria, free of any alcohol consumption during the last 15 days, and without
             any other DSM-IV criteria

          -  22 healthy controls paired for gender, age and educational level with
             alcohol-dependent participants, without any alcohol consumption during the last three
             days and without any psychiatric or neurological diagnosis.

        All participants will be between 18 and 60 years of age, will be French-speaking and will
        present a normal or corrected-to-normal auditory and visual acuity.
      
Keywords: alcohol-dependence; event-related potentials; emotion; crossmodal; peripheral processing