Resting-state electroencephalographic functional network alterations in major depressive disorder following magnetic seizure therapy

• Published in: Progress in neuro-psychopharmacology & biological psychiatry Vol. 108; p. 110082
• Main Authors: Hill, Aron T., Zomorrodi, Reza, Hadas, Itay, Farzan, Faranak, Voineskos, Daphne, Throop, Alanah, Fitzgerald, Paul B., Blumberger, Daniel M., Daskalakis, Zafiris J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 08.06.2021
• Subjects: Adult; Beta Rhythm - physiology; Brain - physiopathology; Brain networks; Cohort Studies; Connectivity; Depressive Disorder, Major - physiopathology; Depressive Disorder, Major - psychology; Depressive Disorder, Major - therapy; EEG; Electroconvulsive Therapy - methods; Electroencephalography - methods; Female; Humans; Magnetic Field Therapy - methods; Magnetic seizure therapy; Major depressive disorder; Male; Middle Aged; Nerve Net - physiopathology; Psychiatry; Rest - physiology; Rest - psychology; Seizures - physiopathology; Seizures - psychology; Theta Rhythm - physiology; Connectivity; Magnetic seizure therapy; Brain networks; Psychiatry; EEG; Major depressive disorder
• ISSN: 0278-5846; 1878-4216; 1878-4216
• DOI: 10.1016/j.pnpbp.2020.110082

Magnetic seizure therapy (MST) is emerging as a safe and well-tolerated experimental intervention for major depressive disorder (MDD), with very minimal cognitive side-effects. However, the underlying mechanism of action of MST remains uncertain. Here, we used resting-state electroencephalography (RS-EEG) to characterise the physiological effects of MST for treatment resistant MDD. We recorded RS-EEG in 21 patients before and after an open label trial of MST applied over the prefrontal cortex using a bilateral twin coil. RS-EEG was analysed for changes in functional connectivity, network topology, and spectral power. We also ran further baseline comparisons between the MDD patients and a cohort of healthy controls (n = 22). Network-based connectivity analysis revealed a functional subnetwork of significantly increased theta connectivity spanning frontal and parieto-occipital channels following MST. The change in theta connectivity was further found to predict clinical response to treatment. An additional widespread subnetwork of reduced beta connectivity was also elucidated. Graph-based topological analyses showed an increase in functional network segregation and reduction in integration in the theta band, with a decline in segregation in the beta band. Finally, delta and theta power were significantly elevated following treatment, while gamma power declined. No baseline differences between MDD patients and healthy subjects were observed. These results highlight widespread changes in resting-state brain dynamics following a course of MST in MDD patients, with changes in theta connectivity providing a potential physiological marker of treatment response. Future prospective studies are required to confirm these initial findings. •We utilised rest EEG to characterise physiological changes following MST in MDD.•MST significantly altered functional connectivity, network topology, and spectral power.•Changes in theta connectivity predicted clinical response to MST.•Rest EEG is a sensitive marker of neural response to MST.