Multidisciplinary approaches to understandingauditory hallucinationsFlavie Waters – University of Western Australia, PerthPaul Allen – Institute of Psychiatry, LondonJudith Ford – University of California, San FranciscoIris Sommer - University Medical Center UtrechtWEBINAR THURSDAY, 13 SEPTEMBER 2012 AT 10 A.M., EST (2 P.M.,GMT).WWW.SCHIZOPHRENIAFORUM.ORG
• 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
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.
Some questions of interest:i) Are the brain mechanisms underlying auditory hallucinations similar, ordifferent, across diagnostic groups?ii) Which brain mechanisms are specific to auditory hallucinations, andindependent of symptoms that commonly co-occur with auditoryhallucinations?
Cognitive processesAuditory Hallucinations in schizophrenia and schizoaffective disorder
Voices start with a neural signalJardri 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
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
1. Raw signal as ‘hallucinogenic’ 1st hit Emotions play an important role2. Trigger: environmental circumstances,internal events 2nd hit3. The signal is shaped by top-downprocesses: - signal detection - source memory - inhibitory control processes - past experiences - ‘state’ and ‘trait’ characteristics
Cognitive processesAuditory Hallucinations in other population groups
Raw signal for hallucinations in nonpsychotic (non-psychiatric) population alsocomes from inferior frontal gyrus, and the right temporal speech-processingregion 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.
Cognitive processes – other populationsSIGNAL DETECTION INHIBITORY SOURCE MEMORY + Negative PROCESSES EmotionsThere is lower Difficulties identifyingthreshold in Breakdown in ability to the origins of eventsaccepting a signal as control thoughts, and PASTreal ‘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