This month has seen a mass of voice-hearing research, so much in fact that my summaries are going to have to be a bit shorter this month because, sadly, I do have to sleep at some point. Man, I miss being in my twenties.
Schizophrenia Bulletin Special Section
This month five papers were published in a special section of the journal Schizophrenia Bulletin. These were the result of five working groups formed last year at the International Consortium on Hallucination Research, and were co-written by researchers from across the world working together.
Aside from papers explictly on hearing voices, I’d also draw your attention to another paper in this edtion of Schizophrenia Bulletin, by Filippo Varese and colleagues showing that childhood adversities increase the risk of developing psychosis. This paper also has the benefit of being freely available, and you can download it here.
Accessible summary: This paper looks at what research has established about what voices are like in the context of schizophrenia, and a range of other conditions including substance abuse, Parkinson’s disease, epilepsy, dementia, late-onset schizophrenia, mood disorders, borderline personality disorder, hearing impairment, and dissociative disorders. The paper also looks at voice-hearing in non-psychiatric populations, and then points towards directions for future research.
Link to paper: http://dx.doi.org/10.1093/schbul/sbs061
Accessible summary: The paper reviews the existing literature and then argues that voice-hearing results firstly from abnormal activation of the auditory system, creating an auditory signal. Deficits in the ability to tell whether something was produced by oneself or another then cause this signal to be accepted as real. The person’s prior history (which may include trauma) and memories then give the auditory signal personal relevance, and depression/anxiety/paranoia/fear then contribute to the person’s beliefs about their voices.
Link to paper: http://dx.doi.org/10.1093/schbul/sbs045
Accessible summary: This paper reviews what a range of neuroimaging studies have told us about voice-hearing, highlighting changes in areas of the brain involved in producing and perceiving speech and language. They also note areas that have hindered progress in this area and make recommendations for future studies.
Link to paper: http://dx.doi.org/10.1093/schbul/sbs066
Accessible summary: This paper looks at what we have learnt from EEG (electroencephalography) studies (which the measure electrical signals of the brain) and MEG (magnetoencephalography) studies (which measure magnetic changes in the brain). This paper is hard to summarise but points to a range of interconnections between the frontal lobe of the brain and the temporal lobe of the brain in generating voice-hearing experiences.
Link to paper: http://dx.doi.org/10.1093/schbul/sbs009
Accessible summary: The paper concludes that antipsychotic medication “is capable of inducing a rapid
decrease in hallucination severity” and that “only 8% of the
first-episode patients go on to experience mild, moderate,
or severe hallucinations when they continue their medication
as prescribed during 1 year”. They also note that cognitive behavioural therapy can “be applied as an augmentation to antipsychotic medication”, and that transcranial magnetic stimulation (which involves clinicians/researchers applying a rapidly changing magnetic field over specific part of the brain) is capable of reducing the frequency and severity of auditory hallucinations. They also conclude that the effect of electroconvulsive therapy on hallucinations “is as yet unclear and might well be low”.
Link to paper: http://dx.doi.org/10.1093/schbul/sbs034
Other papers published this month
Sydney, Australia. This is one of my own offerings, which was also in the latest edition of Schizophrenia Bulletin. I propose that neurofeedback might be a useful technique to help some people with their voices.
Accessible summary: Neurofeedback is a way in which you can control the activity of your own brain. By lying in an fMRI scanner, or sitting with an EEG cap on your head, you can be shown the ongoing activity in a specific region of your brain. You can then learn to make this activity go up or down at will, by using a range of self-learnt techniques. Once outside of the scanner you can then use these techniques to alter the activity of your brain in your ongoing life. Given that we know what parts of the brain are activated when people hear voice (i.e., when they have auditory hallucinations), in theory if people could learn to control activity in these specific parts of their brain, they could obtain more control over their voices. Thus, if neither medication nor trying to make sense of voices in the context of one’s life has been helpful, a new option might be to try neurofeedback. I sketch out a few ideas as to how this might work in practice.
Link to paper: http://dx.doi.org/10.1093/schbul/sbs006
Accessible summary: The paper looksat how what we know about the auditory processing system can be linked to hearing voices, and what we know about the neurophysiology of the experience.
Link to paper: http://dx.doi.org/10.1055/s-0032-1315728
Accessible summary: The authors note that the somewhat trivialising term ‘pseudohallucination’ is often applied to the voices heard by people with BPD. They compared the voices heard by people with BPD with those of people with schizophrenia, and found no significant differences between them. Just like people diagnosed with schizophrenia who hear voices, those diagnosed with BPD who heard voices “experienced AVH for long periods of time, with a high frequency, and high levels of ensuing distress” (p. 1877).
Link to paper: http://dx.doi.org/10.1017/S0033291712000165
Accessible summary: This is tricky for me to summarise in a clear way. I’ll try though. Ok, so, at any given time we have loads of different types of information such as sights, sounds, smells, all coming in at us. The question as to how the brain knits this all together into one coherent experience is called the ‘binding problem’. One answer to this question is that when neurons in different parts of the brain vibrate at the same frequency (40Hz), this causes a coherent experience to arise. Imagine people humming different sounds at the same time, you would get a racket. If people all hum the same sound, then this amplifies into a coherent, resonant sound. It’s the same basic idea, but with 40Hz being a key frequency here for the brain.
The researchers played different frequency sounds (20Hz, 30Hz, and 40Hz) to participates and examined what their brains did. Basically, they found that the 40Hz sounds increased synchrnoisation between different parts of the brain in people who didn’t hear voices (i.e., a bit like different parts of their brain all humming the same note). However, in people who heard voices, the opposite occurred, with different parts of their brains becoming less sychronised (i.e., it was a bit like if two parts of their brain had initially been humming similar tunes, e.g., two different Hendrix songs, then after the 40Hz sound, one part of their brain carried on humming Hendrix and another other starting humming James Taylor). This effect was specific to people who heard voices, and not just schizophrenia per se. The authors speculate this effect was found because the brains of people who heard voices were already doing some extra auditory processing, and that the 40Hz sound interfered with this.
My summary here is not going to win any prizes for good science writing, so if you are interested in this study, but not that familiar with the science in this area, I would suggest contacting the authors directly for a clearer accessible summary (E-mail: thomas.koenig at puk.unibe.ch).
Link to paper: http://dx.doi.org/10.1016/j.schres.2012.07.016
Accessible summary: EMDR basically involves thinking of a negative or distressing memory, then making a series of side-to-side eye movements, e.g., watching an object moving from side to side. All this is done with a trained therapist. There is not much out there on EMDR and hallucinations, but this paper reports three case studies, suggesting that it may be of use as part of a wider therapeutic regime involving CBT. This is by no means clear or strong evidence for EMDR for voice-hearing, but if this is an area you are interested in, then the paper may be of some use. (Also see this other earlier paper if you are interested in EMDR and hearing voices).
Pdf of paper: Available here.
(Apologies for the photo – so much research comes out of the Netherlands that I am running out of new images).
That’s all for this month folks. Au revior from Sydney, where it snowed this month. Well, when I say snowed, I mean there were controlled forest fire burns nearby and ash floated down, but that’s as near to snow as we’re going to get here. They also started selling mince pies in the supermarkets (hurrah!) so its been a Christmassy week all round.