Differential resting-state functional connectivity patterns in functional movement disorders: Evidence for gait-disorder-specific aberrations.

BACKGROUND

The clinical presentation of Functional Movement Disorders (FMD) is highly variable, encompassing gait disturbances and a wide range of hyper- and hypokinetic movement abnormalities. The neurobiological correlates distinguishing different phenotypes, particularly functional gait disorders, remain poorly understood.

OBJECTIVE

To investigate whether functional gait disorders are associated with specific patterns of resting-state functional connectivity that distinguish them from other FMD phenotypes.

METHODS

Thirty-eight FMD patients (9 with isolated gait disorders, 9 with combined gait and other motor symptoms, 20 with non-gait motor symptoms) and 20 healthy controls underwent resting-state functional MRI. Using seed-based connectivity analysis with eight bilateral regions of interest of the general, non FMD-specific motor network, we examined functional connectivity patterns across groups.

RESULTS

Seed-based functional connectivity analysis revealed decreased connectivity between the left caudate nucleus and the left temporoparietal junction across gait disorder groups compared to both non-gait disorders and healthy controls. Patients with gait disorders showed decreased interhemispheric connectivity between primary sensorimotor areas compared to non-gait disorder patients, but partially increased connectivity compared to healthy controls. Both isolated and combined gait disorder groups demonstrated characteristic alterations in premotor-sensorimotor connectivity patterns, with distinct profiles between these subgroups.

CONCLUSION

Our findings suggest distinct neurobiological signatures in functional gait disorders compared to other functional movement phenotypes. These findings might reflect specific pathophysiological mechanisms underlying functional gait disorders, particularly involving sensory feedback integration and motor control. These results provide new insights into the neurobiological basis of different FMD phenotypes and may contribute to the development of targeted therapeutic approaches.