Cognitive vulnerability to auditory hallucination. Preferred imagery mode and spatial location of sounds

Examining the relationships between cognition and auditory hallucinations: A systematic review

OBJECTIVE

Auditory hallucinations (hearing voices) have been associated with a range of altered cognitive functions, pertaining to signal detection, source-monitoring, memory, inhibition and language processes. Yet, empirical results are inconsistent. Despite this, several theoretical models of auditory hallucinations persist, alongside increasing emphasis on the utility of a multidimensional framework. Thus, clarification of current evidence across the broad scope of proposed mechanisms is warranted.

METHOD

A systematic search of the Web of Science, PubMed and Scopus databases was conducted. Records were screened to confirm the use of an objective behavioural cognitive task, and valid measurement of hallucinations specific to the auditory modality.

RESULTS

Auditory hallucinations were primarily associated with difficulties in perceptual decision-making (i.e. reduced sensitivity/accuracy for signal-noise discrimination; liberal responding to ambiguity), source-monitoring (i.e. self-other and temporal context confusion), working memory and language function (i.e. reduced verbal fluency). Mixed or limited support was observed for perceptual feature discrimination, imagery vividness/illusion susceptibility, source-monitoring for stimulus form and spatial context, recognition and recall memory, executive functions (e.g. attention, inhibition), emotion processing and language comprehension/hemispheric organisation.

CONCLUSIONS

Findings were considered within predictive coding and self-monitoring frameworks. Of concern was the portion of studies which - despite offering auditory-hallucination-specific aims and inferences - employed modality-general measures, and/or diagnostic-based contrasts with psychologically healthy individuals. This review highlights disparities within the literature between theoretical conceptualisations of auditory hallucinations and the body of rigorous empirical evidence supporting such inferences. Future cognitive investigations, beyond the schizophrenia-spectrum, which explicitly define and measure the timeframe and sensory modality of hallucinations, are recommended.

Self-recognition deficits in schizophrenia patients with auditory hallucinations: a meta-analysis of the literature

Theories about auditory hallucinations in schizophrenia suggest that these experiences occur because patients fail to recognize thoughts and mental events as self-generated. Different theoretical models have been proposed about the cognitive mechanisms underlying auditory hallucinations. Regardless of the cognitive model being tested, however, experimental designs are almost identical in that they require a judgment regarding whether an action was self-originated or not. The aim of the current study was to integrate all available literature for a meta-analysis on this topic and reach conclusions about self-recognition performance in (1) patients with schizophrenia compared with healthy controls and (2) patients with auditory hallucinations compared with patients without these symptoms. A comprehensive literature review identified 23 studies that contrasted the performance of schizophrenia patients with healthy controls (1370 participants) and 9 studies that directly compared patients with and without auditory hallucinations (315 participants). We found significantly reduced self-recognition performance in schizophrenia patients, which was more pronounced in patients with auditory hallucinations compared with patients without. In patients with hallucinations, this pattern of performance was specific to self-recognition processes and not to the recognition of new external information. A striking finding was the homogeneity in results across studies regardless of the action modality, timing delay, and design used to measure self-recognition. In summary, this review of studies from the last 30 years substantiates the view that self-recognition is impaired in patients with schizophrenia and particularly those with auditory hallucinations. This suggests an association, perhaps a causal one, between such deficit and hallucinatory experiences in schizophrenia.

Auditory hallucinations: expectation-perception model

In this paper, we aimed to present a hypothesis that would explain the mechanism of auditory hallucinations, one of the main symptoms of schizophrenia. We propose that auditory hallucinations arise from abnormalities in the predictive coding which underlies normal perception, specifically, from the absence or attenuation of prediction error. The suggested deficiencies in processing prediction error could arise from (1) abnormal modulation of thalamus by prefrontal cortex, (2) absence or impaired transmission of external input, (3) dysfunction of the auditory and association cortex, (4) neurotransmitter dysfunction and abnormal connectivity, and (5) hyperactivity activity in auditory cortex and broad prior probability. If there is no prediction error, the initially vague prior probability develops into an explicit percept in the absence of external input, as a result of a recursive pathological exchange between auditory and prefrontal cortex. Unlike existing explanations of auditory hallucinations, we propose concrete mechanisms which underlie the imbalance between perceptual expectation and external input. Impaired processing of prediction error is reflected in reduced mismatch negativity and increased tendency to report non-existing meaningful language stimuli in white noise, shown by those suffering from auditory hallucinations. We believe that the expectation-perception model of auditory hallucinations offers a comprehensive explanation of the underpinnings of auditory hallucinations in both patients and those not diagnosed with mental illness. Therefore, our hypothesis has the potential to fill the gaps in the existing knowledge about this distressing phenomenon and contribute to improved effectiveness of treatments, targeting specific mechanisms.

Verbal hallucinations and language production processes in schizophrenia

How is it that many schizophrenics identify certain instances of verbal imagery as hallucinatory? Most investigators have assumed that alterations in sensory features of imagery explain this. This approach, however, has not yielded a definitive picture of the nature of verbal hallucinations. An alternative perspective suggests itself if one allows the possibility that the nonself quality of hallucinations is inferred on the basis of the experience of unintendedness that accompanies imagery production. Information-processing models of “intentional” cognitive processes call for abstract planning representations that are linked to goals and beliefs. Unintended actions - and imagery - can reflect planning disruptions whereby cognitive products do not cohere with concurrent goals. A model of schizophrenic speech disorganization is presented that postulates a disturbance of discourse planning. Insofar as verbal imagery can be viewed as inwardly directed speech, a consequence of such planning disturbances could be the production of unintended imagery. This link between the outward disorganization of schizophrenic speech and unintended verbal imagery is statistically supported by comparing the speech behavior of hallucinating and nonhallucinating schizophrenics. Studies of “borderline” hallucinations during normal, “goal-less” relaxation and drowsiness suggest that experiential unintendedness leads to a nonpathological variant of hallucinatory otherness that is correctable upon emerging from such passive cognitive states. This contrasts with the schizophrenic case, where nonconcordance with cognitive goals reinforces the unintendedness of verbal images and sustains the conviction of an external source. This model compares favorably with earlier models of verbal hallucinations and provides further evidence for a language production disorder in many schizophrenics.Short Abstract: How is it that many schizophrenics identify certain instances of verbal imagery as hallucinatory? This paper proposes that the critical feature identifying hallucinations is the experience of unintendedness. This experience is nonpathological during passive conscious states but pathological if occurring during goal-directed cognitive processing. A model of schizophrenic speech disorganization is presented that postulates a disturbance of discourse planning that specifies communicative intentions. These alterations could generate unintended verbal imagery as well. Statistical data are offered to support the model, and relevant empirical studies are reviewed.

Kognitive Verhaltenstherapie von Wahn und Halluzinationen

Zusammenfassung. Theoretischer Hintergrund: In den letzten 10-15 Jahren sind eine Reihe von kognitiv-behavioralen Interventionen entwickelt und evaluiert worden, die auf eine direkte Reduktion von Wahn und Halluzinationen abzielen. Gleichzeitig mehren sich Arbeiten aus der Grundlagenforschung zu Schizophrenie, die darauf hindeuten, dass Wahn und Halluzinationen mit spezifischen kognitiven Verarbeitungsstilen assoziiert sind. Als solche gelten unter anderem voreiliges Schlussfolgern, Schwierigkeiten in der Perspektivenübernahme (Theory-of-Mind), external-personale Attributionsstile und fehlerhafte Quellenattribution. Ziele: 1) die wichtigsten experimentellen Untersuchungen und Ergebnisse zu kognitiven Prozessen bei Wahn und Halluzinationen verständlich darzustellen, 2) eine Einführung in die therapeutischen Interventionen zur Veränderung der Symptome zu bieten und 3) zu bewerten, inwieweit die experimentellen Befunde in die Entwicklung von Therapiestrategien zu Wahn und Halluzinationen eingeflossen sind, bzw. durch spezifische Befunde gedeckt werden. Schlussfolgerungen: Die Mehrzahl der Interventionen setzt indirekt an den gefundenen kognitiven Auffälligkeiten an, wobei offen bleibt, in wie weit ihre Wirkung auf eine Veränderung der kognitiven Verarbeitungsstile zurückgeht. Obwohl die kognitive Umstrukturierung dysfunktionaler Selbstkonzepte einen wesentlichen Bestandteil der kognitiven Interventionen darstellt, ist die empirische Evidenz für die Rolle negativer Selbstkonzepte bei der Entstehung von Wahn und Halluzinationen bislang uneindeutig.

Neuropsychological correlates of reality distortion in schizophrenic patients

The present study aims at exploring the relationship between content-related aspects of delusions and hallucinations in schizophrenia and the basic domains of cognition, controlling for the other clinical and demographic variables that could produce bias in the interpretation of the results. Seventy stable schizophrenic patients were evaluated through psychiatric assessment and a neuropsychological battery including tests on attention, memory, perceptual-motor speed and executive functions. We found that the severity of negative symptoms was strongly correlated with poor performance in almost all domains of cognitive functions, while only the attentional deficit was correlated with positive symptoms. The relationships between different cognitive domains and specific types of delusions and hallucinations showed that thought insertion, guilt, grandiose, religious and somatic delusions were associated with impairment in different cognitive functions (verbal and visual memory, attention and executive functions). Voices arguing and tactile hallucinations were correlated to delay-recall memory function. Our results suggest that no specific cognitive pattern is associated with typical-content delusions and hallucinations. On the basis of our findings, cognitive impairments associated with delusions and hallucinations, as measured by our battery, seem not to play a central role in the genesis and the maintenance of these symptoms, suggesting a more complex model of pathogenesis.

Phenomenological features of auditory hallucinations and their symptomatological relevance

Auditory hallucinations include particularly diverse phenomena that reflect various mental functions and pathologies. Their assessment may provide valuable clinical information. This article describes the development of the Matsuzawa Assessment Schedule for Auditory Hallucination (MASAH), which was designed to obtain a broadened view of the phenomena by investigating a wide range of their characteristics. The aim was to identify the basic phenomenological features of auditory hallucinations by performing a factor analytic study of the MASAH ratings of 214 patients with schizophrenia or schizoaffective disorder. Four identified factors were intractability, delusion, influence, and externality, on the basis of which we constructed composite scales that were assumed to represent the features. The correlation analysis of the scales with symptom dimensions derived from the positive and negative syndrome scale verified their clinical relevance. They were also interpretable in terms of human responses to the abnormal experience and some symptom constructs such as delusion and influence experience. It is concluded that the MASAH is an efficient means for evaluating the features, and that this study elicited new understandings of the phenomena such as their multifarious composition and contiguities with other psychotic symptoms.

Defensive projection and paranoid delusions

The present study considered the implication of a new explanation of defensive projection for the thematic qualities of schizophrenic delusions. Projection was proposed to be a form of self-deception practiced by people who make excessive use of social comparison in self-evaluation. Defensive projection occurs when an unacceptable quality is minimized by distorting this quality in other people used as standards of comparison. Reactive paranoid schizophrenics were expected to show projection as a distortion of social comparison and process paranoid schizophrenics were not. This was tested in terms of a number of thematic qualities that should appear in actual delusions of reactive paranoids but not in those of process paranoids (i.e. more specific social references, attribution of untrustworthiness by men, attribution of hostility by women, concern with female identity in women). The results confirmed these predictions and supported the social-comparison interpretation of projection as a defense in reactive schizophrenics that contributes to the development of delusions.

Cognitive vulnerability to auditory hallucination. Impaired perception of meaning

Forty-four psychiatric patients were separated into four groups on the basis of presence/absence of hallucinations and reactive/process status. Reactive hallucinators were found to be singularly impaired in two aspects of cognitive processing: (1) tolerance of ambiguity; and (2) availability of alternative meanings. The perceptual errors produced by premature judgment and limited consideration of alternative meanings for misperceptions are discussed as factors predisposing to auditory hallucination.