fMRI Analysis of Dissociative Convulsions: A Case-Controlled Study

Dissociative convulsions represent complex biopsychosocial etiopathogenesis and have semiological similarities with epilepsy, which leads to delays in definitive diagnosis as well as treatment. We explored the neurobiological underpinnings of dissociative convulsions using a functional magnetic resonance imaging (fMRI) design targeting cognitive, affective, and resting state characteristics in our subjects.

Seventeen female patients with dissociative convulsions without any co-morbid psychiatric or neurological illness and 17 matched healthy controls underwent standardized task-based (affective and cognitive) and resting state fMRI. Blood oxygen level-dependent (BOLD) activation results were compared across the groups, and correlation with the severity of dissociation was measured.

Patients with dissociative convulsions had lower activation in the left cingulate gyrus, left paracentral lobule, right middle and inferior frontal gyrus, right caudate nucleus, and right thalamus. There was increased resting state functional connectivity (FC) between the left posterior superior temporal gyrus and left superior parietal lobule; left amygdala and Default Mode Network (DMN) of right lateral parietal cortex; right supramarginal gyrus and left cuneus in the patient group. Patients also had decreased FC between the anterior cingulate cortex (ACC) and left thalamus; ACC and right central opercular cortex; DMN of PCC, posterior cingulate gyrus, and right middle temporal lobe.

Patients with dissociative convulsions have significant deficits in the areas associated with the processing of emotional, cognitive, memory, and sensory-motor functions. There is a significant correlation between dissociative severity and the functioning of areas involving the processing of emotions, cognition, and memory.