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Mechanisms Underlying Auditory Hallucinations-Understanding Perception without Stimulus.

Tracy DK, Shergill SS - Brain Sci (2013)

Bottom Line: Disappointingly many AVH remain resistant to standard treatments and persist for many years.Our understanding of AVH remains incomplete though much progress has been made in recent years.We herein provide a broad overview and review of this.

View Article: PubMed Central - PubMed

Affiliation: Cognition, Schizophrenia & Imaging Laboratory, Department of Psychosis Studies, Institute of Psychiatry, King's College London, London SE5 8AF, UK. derek.tracy@oxleas.nhs.uk.

ABSTRACT
Auditory verbal hallucinations (AVH) are a common phenomenon, occurring in the "healthy" population as well as in several mental illnesses, most notably schizophrenia. Current thinking supports a spectrum conceptualisation of AVH: several neurocognitive hypotheses of AVH have been proposed, including the "feed-forward" model of failure to provide appropriate information to somatosensory cortices so that stimuli appear unbidden, and an "aberrant memory model" implicating deficient memory processes. Neuroimaging and connectivity studies are in broad agreement with these with a general dysconnectivity between frontotemporal regions involved in language, memory and salience properties. Disappointingly many AVH remain resistant to standard treatments and persist for many years. There is a need to develop novel therapies to augment existing pharmacological and psychological therapies: transcranial magnetic stimulation has emerged as a potential treatment, though more recent clinical data has been less encouraging. Our understanding of AVH remains incomplete though much progress has been made in recent years. We herein provide a broad overview and review of this.

No MeSH data available.


Related in: MedlinePlus

The feed-forward model of auditory verbal hallucinations (AVH). Failure to send an efference copy of intended inner speech leads to a comparator mismatch between sensory experience and expectation, leading potentially either to a sense of “unintendedness” (Seal’s model) or “other authorship” (Jones’ and Fernyhough’s model). Top-down factors contribute to a propensity to further misattribute this perception as alien, and over time lowered thresholds to accept such as external may arise, with “hard-wiring” of the voices. Signal Detection Theory gives greater weight to the role of top down factors, but is compatible with the other aspects.
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brainsci-03-00642-f001: The feed-forward model of auditory verbal hallucinations (AVH). Failure to send an efference copy of intended inner speech leads to a comparator mismatch between sensory experience and expectation, leading potentially either to a sense of “unintendedness” (Seal’s model) or “other authorship” (Jones’ and Fernyhough’s model). Top-down factors contribute to a propensity to further misattribute this perception as alien, and over time lowered thresholds to accept such as external may arise, with “hard-wiring” of the voices. Signal Detection Theory gives greater weight to the role of top down factors, but is compatible with the other aspects.

Mentions: Other pathological processes in psychosis, including deficient top-down factors [51] such as episodic memory and past experience, attributional biases, mood, and expectations helped confirm the misperception. A more recent modification by Jones and Fernyhough [52] suggests that the failure of a predicted state results in a lack of agency, with the dysfunctional mismatch of the predictive state and actual sensory experience that led to a sense of external authorship of the “voice”, negating the need of “intendedness”. A further variation of these is the Signal Detection Theory (SDT): under this model the perceptions can be normal (though there could also be aberrant signalling), but there is ambiguity in all signal recognition. The model posits that it is pathological misattribution and source-monitoring that leads to the externalising of the perception, potentially exacerbated by concomitant hypervigilence and perception of threat [53]. Social development studies have shown the ability to trust and mentalisation of the actions of others increases with age [54], but that patients with psychotic illnesses show impairment in them and reduced ability to modify their behaviour in these domains despite feedback [20]. The SDT model is compatible with earlier ones, and has the attraction that—for schizophrenia at least—it links with established cognitive biases and other psychopathology such as delusions, as well as readily offering an explanation of the efficacy of antipsychotic medication for AVH. In all these models time altered expectations may result in a propensity to accept them as real, personalised, definable, and different voices [55]. Figure 1 gives an overview of these models.


Mechanisms Underlying Auditory Hallucinations-Understanding Perception without Stimulus.

Tracy DK, Shergill SS - Brain Sci (2013)

The feed-forward model of auditory verbal hallucinations (AVH). Failure to send an efference copy of intended inner speech leads to a comparator mismatch between sensory experience and expectation, leading potentially either to a sense of “unintendedness” (Seal’s model) or “other authorship” (Jones’ and Fernyhough’s model). Top-down factors contribute to a propensity to further misattribute this perception as alien, and over time lowered thresholds to accept such as external may arise, with “hard-wiring” of the voices. Signal Detection Theory gives greater weight to the role of top down factors, but is compatible with the other aspects.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061847&req=5

brainsci-03-00642-f001: The feed-forward model of auditory verbal hallucinations (AVH). Failure to send an efference copy of intended inner speech leads to a comparator mismatch between sensory experience and expectation, leading potentially either to a sense of “unintendedness” (Seal’s model) or “other authorship” (Jones’ and Fernyhough’s model). Top-down factors contribute to a propensity to further misattribute this perception as alien, and over time lowered thresholds to accept such as external may arise, with “hard-wiring” of the voices. Signal Detection Theory gives greater weight to the role of top down factors, but is compatible with the other aspects.
Mentions: Other pathological processes in psychosis, including deficient top-down factors [51] such as episodic memory and past experience, attributional biases, mood, and expectations helped confirm the misperception. A more recent modification by Jones and Fernyhough [52] suggests that the failure of a predicted state results in a lack of agency, with the dysfunctional mismatch of the predictive state and actual sensory experience that led to a sense of external authorship of the “voice”, negating the need of “intendedness”. A further variation of these is the Signal Detection Theory (SDT): under this model the perceptions can be normal (though there could also be aberrant signalling), but there is ambiguity in all signal recognition. The model posits that it is pathological misattribution and source-monitoring that leads to the externalising of the perception, potentially exacerbated by concomitant hypervigilence and perception of threat [53]. Social development studies have shown the ability to trust and mentalisation of the actions of others increases with age [54], but that patients with psychotic illnesses show impairment in them and reduced ability to modify their behaviour in these domains despite feedback [20]. The SDT model is compatible with earlier ones, and has the attraction that—for schizophrenia at least—it links with established cognitive biases and other psychopathology such as delusions, as well as readily offering an explanation of the efficacy of antipsychotic medication for AVH. In all these models time altered expectations may result in a propensity to accept them as real, personalised, definable, and different voices [55]. Figure 1 gives an overview of these models.

Bottom Line: Disappointingly many AVH remain resistant to standard treatments and persist for many years.Our understanding of AVH remains incomplete though much progress has been made in recent years.We herein provide a broad overview and review of this.

View Article: PubMed Central - PubMed

Affiliation: Cognition, Schizophrenia & Imaging Laboratory, Department of Psychosis Studies, Institute of Psychiatry, King's College London, London SE5 8AF, UK. derek.tracy@oxleas.nhs.uk.

ABSTRACT
Auditory verbal hallucinations (AVH) are a common phenomenon, occurring in the "healthy" population as well as in several mental illnesses, most notably schizophrenia. Current thinking supports a spectrum conceptualisation of AVH: several neurocognitive hypotheses of AVH have been proposed, including the "feed-forward" model of failure to provide appropriate information to somatosensory cortices so that stimuli appear unbidden, and an "aberrant memory model" implicating deficient memory processes. Neuroimaging and connectivity studies are in broad agreement with these with a general dysconnectivity between frontotemporal regions involved in language, memory and salience properties. Disappointingly many AVH remain resistant to standard treatments and persist for many years. There is a need to develop novel therapies to augment existing pharmacological and psychological therapies: transcranial magnetic stimulation has emerged as a potential treatment, though more recent clinical data has been less encouraging. Our understanding of AVH remains incomplete though much progress has been made in recent years. We herein provide a broad overview and review of this.

No MeSH data available.


Related in: MedlinePlus