title: A controlled study on the cognitive effect of alpha neurofeedback training in patients with major depressive disorder.
abstract: Cognitive deficits are core symptoms of depression. This study aims to investigate whether neurofeedback (NF) training can improve working memory (WM) performance in patients with major depressive disorder (MDD). The NF group (n = 40) underwent eight NF sessions and was compared to a non-interventional control group (n = 20). The NF protocol aimed to increase the individual upper alpha power in the parieto-occipital area of the scalp. Main cognitive variable was WM, which was measured pre- and post- training along with other variables such as attention and executive functions. EEG was recorded in both eyes closed resting state and eyes open task-related activity, pre- and post- NF training, and pre- and post- the NF trials within each session. A power EEG analysis and an alpha asymmetry analysis were conducted at the sensor level. Frequency domain standardized low resolution tomography (sLORETA) was used to assess the effect at brain source level. Correlation analysis between the clinical/cognitive and EEG measurements was conducted at both the sensor and brain source level. The NF group showed increased performance as well as improved processing speed in a WM test after the training. The NF group showed pre-post enhancement in the upper alpha power after the training, better visible in task-related activity as compared to resting state. A current density increase appeared in the alpha band (8-12 Hz) for the NF group, localized in the subgenual anterior cingulate cortex (sgACC, BA 25). A positive correlation was found for the NF group between the improvement in processing speed and the increase of beta power at both the sensor and brain source level. These results show the effectiveness of this NF protocol in improving WM performance in patients with MDD.
authors.affiliation: Department of Robotics, Perception and Real Time Group, Aragon Institute of Engineering Research (I3A), University of Zaragoza Zaragoza, Spain ; Department of Computer Science and Systems Engineering (DIIS), University of Zaragoza Zaragoza, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Escolano
authors.affiliation: BitBrain Technologies SL Zaragoza, Spain.
authors.forename: Mayte
authors.initials: M
authors.lastname: Navarro-Gil
authors.affiliation: Department of Mental Health in Primary Care, Aragon Health Sciences Institute (IACS), University of Zaragoza Zaragoza, Spain ; Psychiatric Service in the Miguel Servet University Hospital, University of Zaragoza Zaragoza, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Garcia-Campayo
authors.affiliation: GIPSA-Lab, Département Images et Signal, CNRS, University of Grenoble Grenoble, France.
authors.forename: Marco
authors.initials: M
authors.lastname: Congedo
authors.affiliation: Department of Surgical Sciences, Dunedin School of Medicine, University of Otago North Dunedin, New Zealand.
authors.forename: Dirk
authors.initials: D
authors.lastname: De Ridder
authors.affiliation: Department of Robotics, Perception and Real Time Group, Aragon Institute of Engineering Research (I3A), University of Zaragoza Zaragoza, Spain ; BitBrain Technologies SL Zaragoza, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Minguez
keywords: EEG; cognitive enhancement; major depressive disorder (MDD); neurofeedback (NF); upper alpha (UA); working memory (WM)