Review
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World J Psychiatr. Jun 22, 2015; 5(2): 193-209
Published online Jun 22, 2015. doi: 10.5498/wjp.v5.i2.193
Auditory hallucinations: A review of the ERC “VOICE” project
Kenneth Hugdahl
Kenneth Hugdahl, Department of Biological and Medical Psychology, University of Bergen, 5009 Bergen, Norway
Kenneth Hugdahl, Division of Psychiatry, and Department of Radiology, Haukeland University Hospital, 5021 Bergen, Norway
Kenneth Hugdahl, NORMENT Center of Excellence, University of Bergen, 5009 Bergen, Norway
Kenneth Hugdahl, K G Jebsen Center for Neuropsychiatric Disorders, University of Bergen, 5009 Bergen, Norway
Author contributions: Hugdahl K solely contributed to this paper.
Supported by European Research Council Advanced Grant, No. #249516; Research Council of Norway FRIBIOMED Grant, No. 807696; and SFF Grant, No. 222373.
Conflict-of-interest: The author declares no conflict-of-interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Kenneth Hugdahl, Professor, Department of Biological and Medical Psychology, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway. hugdahl@psybp.uib.no
Telephone: +47-55-586277
Received: September 19, 2014
Peer-review started: September 20, 2014
First decision: October 14, 2014
Revised: March 25, 2015
Accepted: April 10, 2015
Article in press: April 14, 2015
Published online: June 22, 2015
Processing time: 272 Days and 17.6 Hours
Abstract

In this invited review I provide a selective overview of recent research on brain mechanisms and cognitive processes involved in auditory hallucinations. The review is focused on research carried out in the “VOICE” ERC Advanced Grant Project, funded by the European Research Council, but I also review and discuss the literature in general. Auditory hallucinations are suggested to be perceptual phenomena, with a neuronal origin in the speech perception areas in the temporal lobe. The phenomenology of auditory hallucinations is conceptualized along three domains, or dimensions; a perceptual dimension, experienced as someone speaking to the patient; a cognitive dimension, experienced as an inability to inhibit, or ignore the voices, and an emotional dimension, experienced as the “voices” having primarily a negative, or sinister, emotional tone. I will review cognitive, imaging, and neurochemistry data related to these dimensions, primarily the first two. The reviewed data are summarized in a model that sees auditory hallucinations as initiated from temporal lobe neuronal hyper-activation that draws attentional focus inward, and which is not inhibited due to frontal lobe hypo-activation. It is further suggested that this is maintained through abnormal glutamate and possibly gamma-amino-butyric-acid transmitter mediation, which could point towards new pathways for pharmacological treatment. A final section discusses new methods of acquiring quantitative data on the phenomenology and subjective experience of auditory hallucination that goes beyond standard interview questionnaires, by suggesting an iPhone/iPod app.

Keywords: Auditory verbal hallucinations; Perception; Executive functions; Brain imaging; Glutamate; Gamma-amino-butyric-acid; Schizophrenia

Core tip: Auditory hallucinations represent a major symptom in schizophrenia, and the present article reviews recent research with a focus on cognitive and brain markers. Auditory hallucinations are described in a neurocognitive model that sees such experiences as initiated from temporal lobe hyper-activation, not inhibited due to frontal lobe hypo-activation. It is proposed that these patterns of brain activation are mediated by abnormalities of the neurotransmitter glutamate. A new way of collecting symptom data on-line is suggested, based on iPhone app-technology.