Dysfunction in emotion processing underlies functional (psychogenic) dystonia

Abstract

Objective: We sought to determine whether abnormalities in emotion processing underlie functional (psychogenic) dystonia, one of the most common functional movement disorders.

Methods: Motor and emotion circuits were examined in 12 participants with functional dystonia, 12 with primary organic dystonia, and 25 healthy controls using functional magnetic resonance imaging at 4T and a finger-tapping task (motor task), a basic emotion-recognition task (emotional faces task), and an intense-emotion stimuli task.

Results: There were no differences in motor task activation between groups. In the faces task, when compared with the other groups, functional dystonia patients showed areas of decreased activation in the right middle temporal gyrus and bilateral precuneus and increased activation in the right inferior frontal gyrus, bilateral occipital cortex and fusiform gyrus, and bilateral cerebellum. In the intense-emotion task, when compared with the other groups, functional dystonia patients showed decreased activation in the left insular and left motor cortices (compared to organic dystonia, they showed an additional decrease in activation in the right opercular cortex and right motor cortex) and increased activation in the left fusiform gyrus.

Conclusions: Functional dystonia patients exhibited stimulus-dependent altered activation in networks involved in motor preparation and execution, spatial cognition, and attentional control. These results support the presence of network dysfunction in functional dystonia. © 2017 International Parkinson and Movement Disorder Society.

Keywords: Functional dystonia; conversion disorder; emotion processing; fMRI; functional movement disorders; psychogenic dystonia.

Figure 1. Atlas-based subcortical regions of interest selected for connectivity analysis

The anatomical regions of interest included the anterior cingulate gyrus, posterior cingulate gyrus and left and right regions of the uncus/amygdala, thalamus, caudate, and putamen from the Harvard-Oxford Subcortical Atlas and left and right subthalamic nuclei from the Subthalamic Nucleus atlas.

Figure 2. Group differences in the Emotional Faces task-related activation

A. Composite map shows the differences in activation between FD and HC during the Faces task contrasting faces versus a fixation cross as control. Regions of greater activity in FD are shown in red-yellow hues; regions of lower activity in FD in blue hues. B. Composite map showing the differences in activation between FD and OD during the Faces task contrasting faces versus a fixation cross as control. Regions of greater activity in FD are shown in red-yellow hues; regions of lower activity in FD in blue hues. Both group contrasts are thresholded at Z > 2.3 and corrected p<0.05.

Figure 3. Group differences in the CPT-END task-related activation

A. Composite map shows the differences in activation between FD and HC during the CPT-END task contrasting intense emotional images versus squares as control. Regions of lower activity in FD are shown in blue hues and a small region of greater activity in FD is shown in orange. B. Composite map showing differences in activation between FD and OD during the CPT-END task contrasting intense emotional images versus squares. Regions of lower activity in FD are shown in blue hues. Both group contrasts are thresholded at Z > 2.3 and corrected p<0.05.