Impaired self-agency in functional movement disorders: A resting-state fMRI study

Abstract

Objective: To investigate the neural mechanisms underlying impaired self-agency in patients with functional movement disorders using resting-state functional MRI (fMRI).

Methods: We obtained resting-state fMRI on 35 patients with clinically definite functional movement disorders and 35 age- and sex-matched healthy controls. Between-group differences in functional connectivity from the right temporo-parietal junction (TPJ), a region previously demonstrated to play a critical role in self-agency by comparing internal predictions of movement with actual external events, were assessed using t tests. All participants were screened for psychiatric diagnoses using a structured clinical interview and completed the Beck Depression Inventory and Childhood Trauma Questionnaire.

Results: Compared to the healthy controls, patients with functional movement disorders showed decreased functional connectivity between the right TPJ and the right sensorimotor cortex, cerebellar vermis, bilateral supplementary motor area, and right insula. These findings were independent of depression, anxiety, and childhood trauma scores included in our assessment as covariates.

Conclusions: The decreased functional connectivity between the right TPJ and bilateral sensorimotor regions observed in patients with functional movement disorders supports a model whereby impaired motor feed-forward together with altered sensory feedback from sensorimotor regions and areas of sensorimotor integration to the right TPJ contributes to patients' impaired sense of self-agency.

Figure 1. Decreased functional connectivity (FC) between the right temporo-parietal junction (rTPJ) and bilateral sensorimotor regions in patients with functional movement disorders (FMD)

Maps demonstrate group differences in rTPJ resting-state FC between patients with FMD and healthy controls. Images show decreased FC in patients with FMD between the rTPJ (seed) and the (A) bilateral supplementary motor area (SMA) (circled), (B) right precentral gyrus (circled), (C) right postcentral gyrus (circled), (D) right insula (circled), and (E) cerebellar vermis (circled). The threshold for display was set at p < 0.02; cluster size >28 voxels.

Figure 2. Childhood emotional trauma differentially affects right temporo-parietal junction (rTPJ) functional connectivity (FC) in patients with functional movement disorders (FMD)

Connectivity map and scatterplot demonstrate group differences in correlation between rTPJ resting-state FC to left insula and levels of childhood emotional trauma. Connectivity map (A) and adjacent scatterplot (B) demonstrate rTPJ FC in patients with FMD compared to healthy controls (HCs) with increasing levels of childhood emotional abuse. Scatterplot shows the relationship between mean z connectivity values and Childhood Trauma Questionnaire emotional abuse subscore for patients and HCs.