June; a record month for rain in the UK, and Sydney hasn’t been dry either. Although I’m not sure what June’s weather has been like in the Netherlands, we’ve been fortunate to have a torrent of voice-hearing papers raining down on us from this corner of the world this month.
NB. In a slightly revised format this month, I’ve decided to continue providing a lay summary of papers, but not a formal detailed summary, as those wanting such a summary can either glean this from the abstract of the paper itself, or consult the paper itself, which I link to.
- Lay summary: The authors investigated whether a new form of talking therapy could reduce levels of depression in people who hear voices. This talking therapy involved 1) finding out why the voices made people feel bad about themselves, 2) asking the voice-hearer to recall and relive happy memories, 3) using these happy memories to challenge the negative things said by the voices, 4) disengaging from the voices and accepting them. They found that although this didn’t change the voices themselves, it did reduce levels of depression.
- Link to paper: http://dx.doi.org/10.1111/j.2044-8260.2011.02025.x
- Lay summary. When we hear things, what we hear is influenced by the sound coming in from the external world (called bottom-up processing), but also by what we expect to hear (called top-down processing). One theory of voice-hearing argues that voice-hearers are more influenced by what they expect to hear, than non voice-hearers, and that this contributes to the formation of hallucinations.
This study gave a task which assesses how much perception is influenced by expectation to 40 patients with a diagnosis of psychosis who heard voices, 40 non-patients who heard voices, and 40 non-patients who didn’t hear voices. The task involved listening to sentences in which the last word was either partially masked by some noise, or simply not there and only noise was played. Of the words which were partially masked by noise, half were words that you would expect the sentence to end in (e.g., The sailor sells his boat) and half were words which you wouldn’t expect the sentence to end in (e.g., The sailor sells his chair). Basically, participants had to press a button to indicate if they had heard a word at the end of the sentence, and if they had, to say what word they thought they had heard. A ‘top-down’ error on the task was defined as being when the participant reported hearing a word that was expected (such as boat in the example above) when an unexpected word had actually been presented (such as chair in the example above).
The authors found that although non-patients who heard voices made more top-down errors than non-voice hearing controls, patients with psychosis who heard voices did not make more top-down errors than non-voice hearing controls. They also found that in the non voice hearing control group that those who were more prone to hallucination-like experience were more likely to make top-down errors. The authors speculate that expectation (i.e., top-down processes) may only play a role in the generation of AVH in nonpsychotic individuals and not in patients with psychosis who hear voices.
- Link to paper: http://dx.doi.org/10.1016/j.schres.2012.06.005
- Musings: The idea that voice-hearers expect to hear certain words, and due to top-down processing overruling bottom-up processing, then come to then actually hear these words as hallucinations does seem a good fit with some types of voice-hearing. For example, this fits in well with Dodgson and Gordon’s (2009) idea of hypervigilance hallucinations. But in my view we should be focussing not on the association between top-down errors and whether one is a patient or non-patient voice-hearer, but with the phenomenology of voices that a person is hearing. If a person hears, for example, a voice which we can view as a hypervigilance hallucination, then it is this we should be trying to link to the presence of top-down errors, and not whether the person is a patient or non-patient.
If somebody wanted an idea for a study, then I would suggest recruiting voice-hearers (patient or non-patient status would be irrelevant here) and splitting them into two groups: those with, and those without hypervigilance hallucinations. I would then test the hypothesis that those with hypervigilance hallucinations would make more top-down errors than those without hypervigilance hallucinations, using the same task employed by Daalman and colleagues (but also including a condition involving words which are personally salient to the voice-hearer and/or related to their voices). If anyone fancied collaborating with me to do this, please let me know.
- Lay summary. People with both hallucinations and delusions have increased persistence of both negative symptoms (e.g., slow movement, slow speech, lack of emotionality) and positive symptoms (e.g., hallucinations & delusions) over time and much higher levels of help-seeking ⁄ impairment compared with the people with only delusions or only hallucinations. Hallucinations (particularly auditory ones) act as a risk factor for the development of delusions.
- Link to paper: http://dx.doi.org/10.1111/j.1600-0447.2012.01888.x
- Lay summary: Basically, functional connectivity analyses involve looking for areas of the brain whose levels of activity mirror each other (i.e., if one area gets excited then the other area gets excited too, and vice versa). This suggests that these two areas of the brain might be linked and be communicating with each other (i.e., are functionally connected). Based on the results of such studies, Hoffman and Hampson propose a model, which basically runs as follows: The putamen region of the brain plays a critical role in the generation of spontaneous language, and in determining whether auditory stimuli are registered consciously as percepts. In voice-hearers this area has a stronger than normal connection with Wernicke’s area, which results in voice-hearing experiences.
- Link to paper: http://dx.doi.org/10.3389/fnhum.2012.00006
That’s all for this month – see you at the end of a hopefully sunny July.