AUTHOR=Benussi Alberto , Premi Enrico , Cantoni Valentina , Compostella Silvia , Magni Eugenio , Gilberti Nicola , Vergani Veronica , Delrio Ilenia , Gamba Massimo , Spezi Raffaella , Costa Angelo , Tinazzi Michele , Padovani Alessandro , Borroni Barbara , Magoni Mauro 

TITLE=Cortical Inhibitory Imbalance in Functional Paralysis

JOURNAL=Frontiers in Human Neuroscience

VOLUME=Volume 14 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2020.00153

DOI=10.3389/fnhum.2020.00153

ISSN=1662-5161

ABSTRACT=Background: Functional movement disorders, are characterized by neurological symptoms that have no identifiable pathology and little is known about their underlying pathophysiology.
Objectives: To analyze motor cortex excitability and intracortical inhibitory and excitatory circuits’ imbalance in patients with flaccid functional weakness.
Methods: Twenty-one consecutive patients with acute onset of flaccid functional weakness were recruited. Single and paired-pulse transcranial magnetic stimulation (TMS) protocols were used to analyze resting motor thresholds (RMT) and intracortical inhibitory (short interval intracortical inhibition - SICI) and excitatory (intracortical facilitation - ICF) circuits’ imbalance between the affected and non-affected motor cortices.
Results: We observed a significant increase in RMT and SICI in the affected motor cortex (p<0.001), but not for ICF, compared to the contralateral unaffected side.
Conclusions: This study extends current knowledge of functional weakness, arguing for a specific central nervous system abnormality which may be involved in symptoms’ pathophysiology.