This document discusses multidisciplinary approaches to understanding auditory hallucinations. It provides information about an upcoming webinar on the topic and related organizations. It also provides statistics on the prevalence of auditory hallucinations in different diagnostic groups. The rest of the document discusses cognitive processes involved in auditory hallucinations in schizophrenia and other populations. It suggests raw signals are shaped by top-down processes like signal detection, source memory, inhibitory control and past experiences. Difficulties with these processes may contribute to the perception of auditory hallucinations across groups.

1. Multidisciplinary approaches to understanding
auditory hallucinations
Flavie Waters – University of Western Australia, Perth
Paul Allen – Institute of Psychiatry, London
Judith Ford – University of California, San Francisco
Iris Sommer - University Medical Center Utrecht
WEBINAR THURSDAY, 13 SEPTEMBER 2012 AT 10 A.M., EST (2 P.M.,
GMT).
WWW.SCHIZOPHRENIAFORUM.ORG

2. • World Hearing Voices Day - Friday 14 September 2012
• International Consortium on Hallucination Research -
http://hallucinationconsortium.org/
• 1st meeting: 13 September 2011
• 2nd meeting: September 2013

3. Auditory hallucinations occur in approx:
• 70% of people diagnosed with schizophrenia and schizoaffective
disorder
• 15% of the healthy population
• 10-20% in Parkinson’s Disease
• 15-50% in Bipolar disorder
• 20-50% in Borderline Personality Disorder.

4. Some questions of interest:
i) Are the brain mechanisms underlying auditory hallucinations similar, or
different, across diagnostic groups?
ii) Which brain mechanisms are specific to auditory hallucinations, and
independent of symptoms that commonly co-occur with auditory
hallucinations?

6. Cognitive processes
Auditory Hallucinations in schizophrenia and schizoaffective disorder

7. Voices start with a neural signal
Jardri R, Pouchet A, Pins D, Thomas P (2011) Cortical Activations During Auditory Verbal Hallucinations
in Schizophrenia: A Coordinate-Based Meta-Analysis. Am J Psychiatry, 168(1), 73-81

8. Top-down processes - schizophrenia
PAST
INHIBITORY EXPERIENCES, FA
SIGNAL DETECTION SOURCE MEMORY NTASY, IMAGERY
PROCESSES
There is lower Difficulties identifying Breakdown in ability to
threshold in the origins of events control thoughts, and
accepting a signal as ‘shift away’ from the
real voices = perception of
reality that is
personally
meaningful.
‘STATE’
CHARACTERISTICS
= random neural = difficulties = auditory signals
activity is processed distinguishing self that are autonomous
when it should have from non-self and difficult to
Delusional
been ignored control
thoughts, lack of
insight contribute to
belief about voices
hypervigilance = sense of reality

9. 1. Raw signal as ‘hallucinogenic’
1st hit
Emotions play an
important role
2. Trigger: environmental circumstances,
internal events 2nd hit
3. The signal is shaped by top-down
processes:
- signal detection
- source memory
- inhibitory control processes
- past experiences
- ‘state’ and ‘trait’ characteristics

10. Cognitive processes
Auditory Hallucinations in other population groups

11. Raw signal for hallucinations in nonpsychotic (non-psychiatric) population also
comes from inferior frontal gyrus, and the right temporal speech-processing
region
3T fMRI scanning MRI - balloon-squeezes as hallucination onsets (Diederen et al
2011)
• Figure. 1. SPM(T)’s for the conjunction analysis revealing brain regions significantly
activated during the experience of AVH in both psychotic and non-psychotic
individuals with AVH (n = 21 in each group). (A) Areas significantly activated within
a priori hypothesized regions. (B) Areas significantly activated within all gray matter
voxels in the brain.

12. Cognitive processes – other populations
SIGNAL DETECTION INHIBITORY SOURCE MEMORY + Negative
PROCESSES
Emotions
There is lower Difficulties identifying
threshold in Breakdown in ability to the origins of events
accepting a signal as control thoughts, and PAST
real ‘shift away’ from the EXPERIENCES,
voices FANTASY,
IMAGERY
= random ‘noise’ is
= auditory signals ‘STATE’
being processed = difficulties CHARACTERISTICS
that are autonomous
and difficult to distinguishing self
control from non-self
hypervigilance