Altered posterior midline activity in patients with jerky and tremulous functional movement disorders.

OBJECTIVE To explore changes in resting-state networks in patients with jerky and tremulous functional movement disorders (JT-FMD). METHODS Resting-state fMRI data from seventeen patients with JT-FMD and seventeen age-, sex-, and education matched healthy controls was investigated. Independent component analysis was used to examine the frontoparietal network (FPN), dorsal attention network (DAN), salience network (SN), and default mode network (DMN). Frequency distribution of network signal fluctuations, intra- and internetwork functional connectivity were investigated. Symptom severity was measured using the Clinical Global Impression-Severity scale. Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI) scores were collected to measure depression and anxiety in FMD, respectively. RESULTS Compared with healthy controls, 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 (PCC) component of the DMN, and in the DAN component (FDR-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. CONCLUSIONS Given the changes in the postero-dorsal 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 impaired attentional control is a fundamental disturbance in these patients.