Selective visual and crossmodal impairment in the discrimination of anger and fear expressions in severe alcohol use disorder.

Background: Severe alcohol use disorder (SAUD) is associated with impaired discrimination of emotional expressions. This deficit appears increased in crossmodal settings, when simultaneous inputs from different sensory modalities are presented. However, so far, studies exploring emotional crossmodal processing in SAUD relied on static faces and unmatched face/voice pairs, thus offering limited ecological validity. Our aim was therefore to assess emotional processing using a validated and ecological paradigm relying on dynamic audio-visual stimuli, manipulating the amount of emotional information available.

Method: Thirty individuals with SAUD and 30 matched healthy controls performed an emotional discrimination task requiring to identify five emotions (anger, disgust, fear, happiness, sadness) expressed as visual, auditory, or auditory-visual segments of varying length. Sensitivity indices (d') were computed to get an unbiased measure of emotional discrimination and entered in a Generalized Linear Mixed Model. Incorrect emotional attributions were also scrutinized through confusion matrices.

Results: Discrimination levels varied across sensory modalities and emotions, and increased with stimuli duration. Crucially, performances also improved from unimodal to crossmodal conditions in both groups, but discrimination for anger crossmodal stimuli and fear crossmodal/visual stimuli remained selectively impaired in SAUD. These deficits were not influenced by stimuli duration, suggesting that they were not modulated by the amount of emotional information available. Moreover, they were not associated with systematic emotional error patterns reflecting specific confusions between emotions.

Conclusions: These results clarify the nature and extent of crossmodal impairments in SAUD and converge with earlier findings to ascribe a specific role for anger and fear in this pathology.