Children with selective mutism: an examination of the attentional and psychophysiological mechanisms underlying the failure to speak and the situational factors that trigger symptomatology
Various prominent models of anxiety have in common that they propose that threatening stimuli processed by an organism lead to a fear response consisting of the components of a threat, attentional processing of the threat, which is subsequently accompanied by processing in brain circuits, and the subsequent physiological fear response. These ... components of the sequence (threat, attention processing, fear response) are essential to understand how symptoms of anxiety disorders occur and are considered in the treatment of anxiety disorders. Accordingly, both transdiagnostic and disorderspecific models of anxiety include the psychophysiological features of altered attention processing and altered autonomic activity as factors contributing to explain phenomenology, etiology, and maintenance of the disorder. Against this background, it is particularly remarkable that these aspects have scarcely been researched yet for the anxiety disorder, selective mutism (SM). Considering that SM is a severely debilitating and typically long-lasting anxiety disorder, it seems crucial to include children with SM to examine these fundamental features of anxiety disorders. A better understanding of these aspects could be the basis for developing targeted therapeutic approaches (e.g., training of attention allocation) and improving already established interventions (e.g., selected appropriate stimuli for exposure) for children with SM. In addition, the question arises whether and how SM differentiates from other anxiety disorders, especially social anxiety disorder (SAD), with which SM has numerous overlaps. The dissertation at hand, based on three studies, provides insights in triggers of anxiety, alterations in attentional processing of threat as well as the autonomic fear response of children with SM. All of these aspects have been largely unexplored, making this dissertation an important addition to the scarce psychophysiological research of SM. As has been shown in other anxiety disorders, including SAD, the project demonstrated that children with SM show signs of restricted autonomic flexibility and are thus likely to respond less adaptively to social stress. In addition, the project provides the first empirical evidence that attentional processing may be altered in children with SM, in that SM symptoms are associated with avoidance of eye contact. The alterations found do not appear to reflect specific psychophysiological processes of SM because these features occur transdiagnostically in children with anxiety disorders. Accordingly, the project’s results suggest that children with SM and SAD do not differ concerning psychophysiological characteristics of attentional processing and autonomic activity. However, the identified anxiety triggers show various triggers can induce anxiety in children with SM. This, in contrast to psychophysiological features, could represent a possible starting point for differentiating SM from other anxiety disorders. In the project at hand, there was also initial evidence for the presence of the potential mechanisms of failure to speak, attentive freezing, and avoidance. Given that the applied paradigms were not designed for differentiating between possible mechanisms of failure to speak, current findings represent only initial evidence on which further research on mechanisms of SM should be built.
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