Altered Posterior Midline Activity in Patients with Jerky and Tremulous Functional Movement Disorders

To explore changes in resting-state networks in patients with jerky and tremulous functional movement disorders (JT-FMD). Resting-state functional magnetic resonance imaging data from seventeen patients with JT-FMD and seventeen age-, sex-, and education-matched healthy controls (HC) were investigated. Independent component analysis was used to examine the central executive network (CEN), salience network, and default mode network (DMN). Frequency distribution of network signal fluctuations and intra- and internetwork functional connectivity were investigated. Symptom severity was measured using the Clinical Global Impression-Severity scale. Beck Depression Inventory and Beck Anxiety Inventory scores were collected to measure depression and anxiety in FMD, respectively. Compared with HC, patients with JT-FMD had significantly decreased power of lower range (0.01-0.10 Hz) frequency fluctuations in a precuneus and posterior cingulate cortex component of the DMN and in the dorsal attention network (DAN) component of the CEN (false discovery rate-corrected p < 0.05). No significant group differences were found for intra- and internetwork functional connectivity. In patients with JT-FMD, symptom severity was not significantly correlated with network measures. Depression scores were weakly correlated with intranetwork functional connectivity in the medial prefrontal cortex, while anxiety was not found to be related to network connectivity. Given the changes in the posterodorsal components of the DMN and DAN, we postulate that the JT-FMD-related functional alterations found in these regions could provide support for the concept that particularly attentional dysregulation is a fundamental disturbance in these patients. Impact statement In this study, we explored static brain network functional connectivity in patients with jerky and tremulous functional movement disorders (JT-FMD) and healthy controls. We studied network functioning by analyzing functional connectivity measures, and also time course frequency spectra, which is novel compared with previous studies. We discovered aberrations in the frequency distribution of a posterior component of the default mode network (precuneus/posterior cingulate) and the dorsal attention network in patients with JT-FMD relative to controls. Conclusively, our findings could provide support for impaired attentional control as a fundamental disturbance in JT-FMD and contribute to the growing conceptualization of this disorder.