The Neuroimaging Evidence of Brain Abnormalities in Functional Movement Disorders

Sanskriti Sasikumar; Antonio P. Strafella

Disclosures

Brain. 2021;144(8):2278-2283. 

In This Article

Discussion

While there is burgeoning evidence to support the neurophysiological changes in FMD,[4,50] the focus of this update is to highlight and interpret the neuroimaging advances in this emerging field. Imaging in FMDs have aided diagnostic clarification as well as provided insights into the underlying aetiology of disease, with structural and functional abnormalities detected in the ventromedial PFC, precuneus, supplementary motor area, DLPFC, anterior corpus callosum and temporo-parietal junction. There is hypoactivation of the cortical and subcortical motor pathways, and increased modulation by the limbic system with heightened emotional arousal and amydgala activity.[51] Sensorimotor integration and voluntary motor inhibition from the prefrontal regions is also impaired, resulting in abnormal motor planning.

We have yet to determine a unified mechanism to explain the phenomenon of FMDs. In addition to the aforementioned limitations, this is also perhaps because of variation in individual responses to stressors, which can further impact the biochemical basis in their condition. Moreover, the predilection and response to stress have a complex underpinning that includes genetic, epigenetic and social influences,[50] which further challenges our interpretation of these findings. Nevertheless, the disrupted neurobiological network suggests the need to reconceptualize our understanding of functional disorders. In recognizing these abnormalities we can no longer distinguish them from the so called 'organic' movement disorders, thus rendering the term 'organic' misleading and deceptive.

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