July, Julius Caesar’s month. Pre-J.C. it had the much more stylish name of Quintilis. Now, going off on what is probably only a degree shy of an tangent, J.C. was possibly the worst kidnapee one could wish for. When pirates kidnapped him in 75BC, and demanded a ransom of 20 talents of silver (equivalent to £270,000), J.C. took offense at this, and insisted they increase this to 50 talents of silver (£675,000). Because he was worth it.
J.C., then demanded that the pirates not talk when he wanted to sleep, and spent most of his time writing and reciting poetry and speeches to the pirates. Now I’m not sure what J.C.’s poetry was like, and whether he would make the top 3 worst poets in the Universe (coming above or below the Vogon’s; god rest Douglas Adams’ soul) but he seems like he would have been pretty insufferable, even for pirates. Although it probably wasn’t a relief for the pirates when they were crucified (which is what J.C., had done to them once he was freed), it may have been close. Anyway, I have significantly digressed. Back to voices.
Accessible summary: The voices people hear may quite often speak to them in the third person (e.g., saying “he’s making a fool of himself” or “she’s being stupid”). Previous research has found that people who hear voices are less likely to be able to successfully recall whether a given action was something they did or something other person did. As a result, research is interested in whether, when voice-hearers take a third person perspective, whether their brains behave differently to non-voice hearers.
What this study did was ask “typically developing” adolescents, and hallucination-prone adolescents (who were either at high risk of developing hallucinations or already experiencing some hallucinations), to do a task where they had to imagine doing things from a 1st person and 3rd person perspective. For example, participant’s had to imagine themselves playing a violin (1st person perspective) and/or their best friend playing the violin (3rd person perspective). All this was done in an fMRI scanner so the researchers could see what people’s brains were up to during the task.
The study found that in the 3rd person condition, hallucination-prone individuals had lower levels of brain activation in the parieto-occipital region of the brain, compared to the “typically developing” group.
So, next question, what does the parieto-occipital region of the brain do? Well, loads of things, but among them is having a hand in episodic memory (i.e., recalling events from one’s past) and being involved in the ability to make distintions between the imagined actions performed by oneself and those performed by other people. The authors hence suggest that one factor related to hearing voices, in addition to effects based in autobiographical memory, may be “impairment in the capacity to shift perspective” which may causes problems in correctly identifying self-produced thoughts in the form of the 3rd person.
Link to paper: http://dx.doi.org/10.3389/fnhum.2013.00329 (free to access)
Accessible summary: This was a single person case study, so should be treated with caution, but is interesting nonetheless. Normal transcranial magnetic stimulation (TMS) involves placing a ping-pong bat like device over a specific part of the scalp. A rapidly changing magnetic field in the bat causes an electric field to be induced in the cortex (surface) of the brain directly below the bat, and alters the activity of this part of the brain, and its connections with other parts of the brain. The magnetic field is usually applied with a frequency of 1Hz. Such 1Hz TMS was done with this patient (over the temporoparietal junction part of the brain), but her voices didn’t improve. However, theta burst stimulation, which uses the same principle but a higher frequency of magnetic field (and has been found to decrease cortical activity) was then applied over the same part of the brain.
The authors report that “on the 8th day of treatment, she reported a total suppression of her AVH [voice-hearing] for at least 5 h and after she had received 18 sessions of cTBS, she was hearing almost no voices and had more than 80% reduction in AHRS [a measure of auditory hallucinations] score from baseline”. The authors suggest the need now for a formal controlled trial of this approach.
Link to paper: http://dx.doi.org/10.1016/j.brs.2013.01.006
Accessible summary: The paper is extremely accessible already and offers a useful discussion of the principles of the HVM, e.g., that using antipsychotics to suppress voices can often be ineffective/insufficient, and voices may actually carry important messages that need to be explored rather than silenced (contrast this to the previous paper above). The paper also makes some intriguing comments based on the authors’ on-going phenomenological work, such as “participants in an in-depth phenomenological study of psychosis we are currently conducting, for example, have reported consciously assigning inherently ambiguous unusual sensory experiences to a single modality (such as voice or sight), focusing on only certain experiences and thus, over time, strengthening those experiences while others drop away”. I would recommend a read of this paper, and I look forward to highlighting the authors’ novel and important detailed phenomenological work when it is published.
Link to paper: http://dx.doi.org/10.3109/01612840.2013.783659
Accessible summary: The superior temporal gyrus (or STG for short), the upper part of the temporal lobe, has been implicated as being involved in voice-hearing for decades. If you directly electrically stimulate it, you will likely hear voices, and neuroimaging studies have shown that it is activated when people experience auditory verbal hallucinations. This study examined the metabolic activity of cells in the STG in people diagnosed with schizophrenia who heard voices but were not on antipsychotic medication. It found that more severe voices were associated with greater changes at a cellular level in the STG. The authors do not go on to say why this relation should exist, and the problem here is that the STG does so many things, but likely to be of importance are the STG’s role in language perception and comprehension, and its role in source-monitoring (working out the source of an event, e.g., whether we thought something or perceived it).
Link to paper: http://dx.doi.org/10.1007/s00429-013-0604-9
- Language lateralisation found not to be associated with severity of voices. Link here.
- Reduced supramarginal cortical thickness (part of the parietal lobe of the brain, involved in many things, including processing heard speech) is predictive of increasing hallucinations over time in Alzheimer’s Disease. Link here.
- Association between hallcination-proneness (but not a specific measure of auditory hallucination-proneness) and a proxy measure of mistaking internally generated thoughts for externally generated ones. Link here.
- A review which touches on the relation between attachment and hallucinations (nothing definitive found). Link here.
- People’s relationships with their voices were found not to change over a 6 month period, when no targetted intervention was used. This suggest that there is the need for a tailored intervention to alter voice-hearers relations with their voices, to help reduce the distress associated with voice-hearing. Link here.
That’s all for this month. More voice-hearing research, and probably digressions (after all, August was named after another Caesar…), next month.