Microstructural integrity of affective neurocircuitry in patients with dissociative seizures is associated with emotional task performance, illness severity and trauma history

Purpose: To identify variations in white matter tract integrity related to behavioural control in response to emotional stimuli in patients with dissociative seizures (DS) and healthy controls (HC), and examine associations with illness characteristics and psychological trauma history.

Methods: Twenty DS patients and 20 HC completed an emotional go/no-go task and questionnaires, and then underwent diffusion tensor imaging (DTI).

Results: Patients had higher false alarm rates in response to negative emotional stimuli than HC. Task performance was correlated with self-reported difficulties in emotional awareness and regulation in everyday life. White matter analysis using tract-based spatial statistics revealed no between-group differences. In patients, fractional anisotropy (FA) in the right uncinate fasciculus, right and left fornix/stria terminalis, and corpus callosum were correlated with task performance. Similar results were found for radial diffusivity (RD), but not mean (MD) or axial diffusivity (AD). In HC, task performance was associated with AD and RD of fewer and smaller clusters in the corpus callosum and right fornix/stria terminalis, and none for FA or MD. Probabilistic tractography of thus identified tracts revealed that mean FA values were correlated with illness parameters (right fornix/stria terminalis with age at onset; posterior corpus callosum with seizure frequency), and psychological trauma history (traumatic experiences during adolescence with anterior corpus callosum).

Conclusions: Patients with DS show impaired behavioural control in response to emotional stimuli. Microstructural variations in task-related neurocircuitry show associations with illness parameters and psychological trauma history. Future studies using psychiatric controls should examine the specificity of these findings.