Reinforcement of vocal correlates of auditory hallucinations by auditory feedback: a case study

Robotically-induced auditory-verbal hallucinations: combining self-monitoring and strong perceptual priors

BACKGROUND

Inducing hallucinations under controlled experimental conditions in non-hallucinating individuals represents a novel research avenue oriented toward understanding complex hallucinatory phenomena, avoiding confounds observed in patients. Auditory-verbal hallucinations (AVH) are one of the most common and distressing psychotic symptoms, whose etiology remains largely unknown. Two prominent accounts portray AVH either as a deficit in auditory-verbal self-monitoring, or as a result of overly strong perceptual priors.

METHODS

In order to test both theoretical models and evaluate their potential integration, we developed a robotic procedure able to induce self-monitoring perturbations (consisting of sensorimotor conflicts between poking movements and corresponding tactile feedback) and a perceptual prior associated with otherness sensations (i.e. feeling the presence of a non-existing another person).

RESULTS

Here, in two independent studies, we show that this robotic procedure led to AVH-like phenomena in healthy individuals, quantified as an increase in false alarm rate in a voice detection task. Robotically-induced AVH-like sensations were further associated with delusional ideation and to both AVH accounts. Specifically, a condition with stronger sensorimotor conflicts induced more AVH-like sensations (self-monitoring), while, in the otherness-related experimental condition, there were more AVH-like sensations when participants were detecting other-voice stimuli, compared to detecting self-voice stimuli (strong-priors).

CONCLUSIONS

By demonstrating an experimental procedure able to induce AVH-like sensations in non-hallucinating individuals, we shed new light on AVH phenomenology, thereby integrating self-monitoring and strong-priors accounts.

The role of inner speech on the association between childhood adversity and 'hearing voices'

Adverse childhood experiences are associated with later development of psychosis, particularly auditory verbal hallucinations and delusions. Although auditory hallucinations have been proposed to be misattributed inner speech, the relation between childhood adversity and inner speech has not been previously investigated. The first aim was to test whether childhood adversity is associated with inner speech in persons with psychosis. The second aim was to test for the influence of inner speech on the association between childhood adversity and auditory hallucinations. Our final aim was to test for evidence that would falsify the null hypothesis that inner speech does not impact the relationship between childhood adversity and delusions. In persons with psychosis, we found a positive association between childhood adversity and dialogic inner speech. There was a significant total effect of childhood adversity on auditory hallucinations, including an indirect effect of childhood adversity on auditory hallucinations via dialogic inner speech. There was also a significant total effect of childhood adversity on delusions, but no evidence of any indirect effect via inner speech. These findings suggest that childhood adversities are associated with inner speech and psychosis. The relation between childhood adversity and auditory hallucination severity could be partially influenced by dialogic inner speech.

Auditory Verbal Hallucinations in Psychosis: Abnormal Perceptions or Symptoms of Disordered Thought?

Auditory verbal hallucinations (AVHs) are considered as hallmark symptoms of psychosis, more specifically of schizophrenia. A substantial body of evidence indicates that AVHs can be attributed to a disorganization of overall speech capacity in psychotic subjects. AVHs are associated with activation of cortical areas of the brain that are related to speech production and perception; "voices" in deaf patients seem to be about the message rather than the sound of it; the content of AVHs is often related to that of delusional ideas; the internal or external location of AVHs makes little diagnostic difference; AVHs are often related to the patient's subvocal speech, having identical content with that, and they have been theorized as a misattribution of inner speech (i.e., the patient's own thoughts) to external sources. The aforementioned evidence comes close to certain long-standing insights mainly of the French psychiatric (de Clérambault) and psychoanalytical (Lacan) school, according to which, 1) the outside world is perceived through normal language function, 2) a language disorder is central to schizophrenic phenomena, and 3) AVHs represent a fragmentation and autonomization of speech (thought) function in schizophrenic patients (de Clérambault: "hallucinations think"). Today, several authors agree that 1) operationalized definitions have led to an oversimplification of psychopathology, and 2) a more theoretically informed understanding and an integration of different levels of explanation of psychotic phenomena is needed. Thus, psychotic AVHs should be investigated beyond their narrow classification as disordered perceptions, in the wider context of formal thought disorder and disordered language capacity.

Attentive Observation Is Essential for the Misattribution of Agency to Self-Performance

Recent studies have repeatedly demonstrated a false memory phenomenon in which people falsely remember having performed an action by oneself when in fact they have only observed the action by another person. We investigated the attentional effect to the action itself on the observation inflation. Fifty-four participants first performed and read actions (Phase 1); then, they observed the action video that showed another's actions (Phase 2), some of which they had not performed in Phase 1. In the Phase 2, they were required to focus on either the actor's performance (i.e., attentive observation condition) or irrelevant objects, which were presented in the background (i.e., inattentive observation condition) to modulate their attention. Around 2 weeks later, participants took a surprise source-memory test (Phase 3). In this phase, we asked them to judge whether they "performed," "read," or "not presented" the action in Phase 1. Three participants were removed from analysis, because they could not attend Phase 3 within 10-16 days after completion of the second phase. We found observation inflation only in the attentive condition, which contradicted the notions from other false memory studies that showed that attention to the target stimuli reduced false memory in general. We discussed the observation inflation mechanism from the perspective of the "like me" system, including the mirror neuron system, self-ownership, and self-agency.

A case of monosymptomatic musical hallucinations

A 61 year old man presented to the psychiatric services with an eight month history of musical hallucinations, unresponsive to neuroleptic medication. Investigation revealed hypertension with brain infarcts in the left temporal and left parietal lobes. Following reassurance that his hallucinations were organic rather than psychiatric in origin, they faded in significance.

Auditory verbal hallucinations as atypical inner speech monitoring, and the potential of neurostimulation as a treatment option

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We discuss ‘inner speech’ theories of auditory verbal hallucinations.

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Atypical self-monitoring may lead to the experience of inner speech as external.

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We summarize research into the use of neurostimulation to treat hallucinations.

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Effects of neurostimulation may be due to modulation of self-monitoring networks.

Auditory verbal hallucinations (AVHs) are the experience of hearing voices in the absence of any speaker, often associated with a schizophrenia diagnosis. Prominent cognitive models of AVHs suggest they may be the result of inner speech being misattributed to an external or non-self source, due to atypical self- or reality monitoring. These arguments are supported by studies showing that people experiencing AVHs often show an externalising bias during monitoring tasks, and neuroimaging evidence which implicates superior temporal brain regions, both during AVHs and during tasks that measure verbal self-monitoring performance. Recently, efficacy of noninvasive neurostimulation techniques as a treatment option for AVHs has been tested. Meta-analyses show a moderate effect size in reduction of AVH frequency, but there has been little attempt to explain the therapeutic effect of neurostimulation in relation to existing cognitive models. This article reviews inner speech models of AVHs, and argues that a possible explanation for reduction in frequency following treatment may be modulation of activity in the brain regions involving the monitoring of inner speech.

From sensorimotor inhibition to freudian repression: insights from psychosis applied to neurosis

First, three case studies are presented of psychotic patients having in common an inability to hold something down or out. In line with other theories on psychosis, we propose that a key change is at the efference copy system. Going back to Freud's mental apparatus, we propose that the messages of discharge of the motor neurons, mobilized to direct perception, also called "indications of reality," are equivalent to the modern efference copies. With this key, the reading of the cases is coherent with the psychodynamic understanding of psychosis, being a downplay of secondary processes, and consequently, a dominance of primary processes. Moreover, putting together the sensorimotor idea of a failure of efference copy-mediated inhibition with the psychoanalytic idea of a failing repression in psychosis, the hypothesis emerges that the attenuation enabled by the efference copy dynamics is, in some instances, the physiological instantiation of repression. Second, we applied this idea to the mental organization in neurosis. Indeed, the efference copy-mediated attenuation is thought to be the mechanism through which sustained activation of an intention, without reaching it - i.e., inhibition of an action - gives rise to mental imagery. Therefore, as inhibition is needed for any targeted action or for normal language understanding, acting in the world, or processing language, structurally induces mental imagery, constituting a subjective unconscious mental reality. Repression is a special instance of inhibition for emotionally threatening stimuli. These stimuli require stronger inhibition, leaving (the attenuation of) the motor intentions totally unanswered, in order to radically prevent execution which would lead to development of excess affect. This inhibition, then, yields a specific type of motor imagery, called "phantoms," which induce mental preoccupation, as well as symptoms which, especially through their form, refer to the repressed motor fragments.

Sense of agency over speech and proneness to auditory hallucinations: The reality-monitoring paradigm

This study investigated the effects of imagining speaking aloud, sensorimotor feedback, and auditory feedback on respondents’ reports of having spoken aloud and examined the relationship between responses to “spoken aloud” in the reality-monitoring task and the sense of agency over speech. After speaking aloud, lip-synching, or imagining speaking, participants were asked whether each word had actually been spoken. The number of endorsements of “spoken aloud” was higher for words spoken aloud than for those lip-synched and higher for words lip-synched than for those imagined as having been spoken aloud. When participants were prevented by white noise from receiving auditory feedback, the discriminability of words spoken aloud decreased, and when auditory feedback was altered, reports of having spoken aloud decreased even though participants had actually done so. It was also found that those who have had auditory hallucination-like experiences were less able than were those without such experiences to discriminate the words spoken aloud, suggesting that endorsements of having “spoken aloud” in the reality-monitoring task reflected a sense of agency over speech. These results were explained in terms of the source-monitoring framework, and we proposed a revised forward model of speech in order to investigate auditory hallucinations.

[Distinguishing the voice of self from others: the self-monitoring hypothesis of auditory hallucination]

Auditory hallucinations (AH), a psychopathological phenomenon where a person hears non-existent voices, commonly occur in schizophrenia. Recent cognitive and neuroscience studies suggest that AH may be the misattribution of one's own inner speech. Self-monitoring through neural feedback mechanisms allows individuals to distinguish between their own and others' actions, including speech. AH maybe the results of an individual's inability to discriminate between their own speech and that of others. The present paper tries to integrate the three theories (behavioral, brain, and model approaches) proposed to explain the self-monitoring hypothesis of AH. In addition, we investigate the lateralization of self-other representation in the brain, as suggested by recent studies, and discuss future research directions.

Auditory hallucinations: nomenclature and classification

INTRODUCTION

The literature on the possible neurobiologic correlates of auditory hallucinations is expanding rapidly. For an adequate understanding and linking of this emerging knowledge, a clear and uniform nomenclature is a prerequisite. The primary purpose of the present article is to provide an overview of the nomenclature and classification of auditory hallucinations.

MATERIALS AND METHODS

Relevant data were obtained from books, PubMed, Embase, and the Cochrane Library.

RESULTS

The results are presented in the form of several classificatory arrangements of auditory hallucinations, governed by the principles of content, perceived source, perceived vivacity, relation to the sleep-wake cycle, and association with suspected neurobiologic correlates.

CONCLUSIONS

This overview underscores the necessity to reappraise the concepts of auditory hallucinations developed during the era of classic psychiatry, to incorporate them into our current nomenclature and classification of auditory hallucinations, and to test them empirically with the aid of the structural and functional imaging techniques currently available.

Monitoring of self-generated speech in adolescents with 22q11.2 deletion syndrome

OBJECTIVES

The present report examines the monitoring of self-generated speech in adolescents with 22q11.2 deletion syndrome (22q11DS), a neurogenetic disorder associated with very high risk for psychosis.

DESIGN

Between-participant group design.

METHODS

In this study, 20 adolescents with 22q11DS, 19 age- and IQ-matched controls, and 19 typically developing adolescents were enrolled. Participants completed a speech-monitoring task, in which they were asked to silently or overtly read a series of word and non-word items. Subjects then filled out a recognition sheet containing studied and novel items. They were asked to identify the previously studied item, and to attribute the reading condition (silent vs. overt) under which each recognized item was encoded.

RESULTS

Adolescents with 22q11DS commit more external attribution errors compared to both control groups, by exhibiting an increased tendency to report silently read items as though they had been read overtly. Further, results suggest that increased cognitive effort exacerbates the external attribution tendency in adolescents with 22q11DS. Increased internal attributions were also observed in the IQcontrol and 22q11DS groups in comparison to typically developing adolescents.

CONCLUSIONS

Similarly to adult individuals exhibiting positive symptoms of psychosis, adolescents with 22q11DS exhibit an external attribution bias for inner speech. This bias seems to be exacerbated by increased cognitive effort, suggesting a failure to recollect information pertaining to cognitive operations during self-monitoring. Cognitive biases associated to schizophrenia may be detected in adolescents at very high risk for psychosis. These observations provide further evidence for the presence of an external attribution bias along the clinical continuum of psychosis vulnerability.

Psychological Treatment of Chronic Auditory Hallucinations: Two Case Studies

Two cases involving the cognitive-behavioural treatment of hallucinations are described. In both cases, a focusing strategy was used with a view to enabling patients to reattribute the nature and meaning of their experiences. One patient showed a marked reduction in the frequency and content of his voices. The second patient showed little change. The implications of observations made during therapy for the future development of cognitive-behavioural strategies for use with psychotic patients are discussed.

The self in action: lessons from delusions of control

Patients with delusions of control are abnormally aware of the sensory consequences of their actions and have difficulty with on-line corrections of movement. As a result they do not feel in control of their movements. At the same time they are strongly aware of the action being intentional. This leads them to believe that their actions are being controlled by an external agent. In contrast, the normal mark of the self in action is that we have very little experience of it. Most of the time we are not aware of the sensory consequences of our actions or of the various subtle corrections that we make during the course of goal-directed actions. We know that we are agents and that we are successfully causing the world to change. But as actors we move through the world like shadows glimpsed only occasional from the corner of an eye.

Being the agent: Memory for action events

Whoever paid the bill at the restaurant last night, will clearly remember doing it. Independently from the type of action, it is a common experience that being the agent provides a special strength to our memories. Even if it is generally agreed that personal memories (episodic memory) rely on separate neural substrates with respect to general knowledge (semantic memory), little is known on the nature of the link between memory and the sense of agency. In the present paper, we review results from two experiments investigating the effects of agency on both explicit and implicit memory traces. Performance of normal subjects is compared to that of schizophrenic patients in order to explore the role of awareness of action on memory. It is proposed that reliable first-person information is necessary to create a stable and coherent motor memory trace.

Making sense of the voices

Hearing voices is a common occurrence, and an experience of many people in psychiatric/mental health care. Nurses are challenged to provide care, which is empowering and helps people who hear voices. Nursing practice undertaken in partnership with the voice hearer and informed by a working explanatory model of hallucinations offers greater helping potential. This paper uses Slade's (1976. The British Journal of Social and Clinical Psychology 15, 415-423.) explanatory model as a framework for exploring interventions which may assist people in exerting some control over the experience and which might be used alongside pharmacological interventions. Principles and practical ideas for how nurses might assist people to cope with and make sense of the experience are explored.

Auditory verbal hallucinations and dysfunction of the neural substrates of speech

OBJECTIVE

to evaluate the neural substrate of auditory verbal hallucinations (AVH), the correlation between AVH and subvocal speech (hereafter SVS), and the relationship between speech and AVH.

METHOD

we reviewed the papers found by an electronic literature search on hallucinations and speech. The review was extended to the papers cited in these publications and to classical works.

RESULTS

there is no conclusive evidence of structural abnormality of the speech perception area in hallucinating schizophrenic patients. However there is evidence of electrophysiological abnormalities of the auditory and speech perception cortices. Functional imaging data are inconsistent, yet point to the left superior temporal gyrus as one of the neural substrates for AVH. There is also evidence that SVS could accompany the experience of AVH.

CONCLUSION

there is evidence that dysfunction of brain areas responsible for speech generation is a fundamental mechanism for generating AVH in schizophrenia. It results in a secondary activation of Wernicke's area (speech perception) and Broca's area (speech expression). The first leading to the experience of hallucinations, and the second, eventually, gives rise to a variable degree of vocal muscle activity detectable by EMG, and/or faint vocalizations detectable by sensitive microphones placed at proximity of the larynx. Direct stimulation or disease of Wernicke's area produces AVH without SVS.

Confusion between silent and overt reading in schizophrenia

The present study was aimed at investigating whether schizophrenic patients are impaired in monitoring their own speech. In particular, we attempted to assess their ability to discriminate between overt and covert speech in a reading task, in order to verify whether they can correctly recollect the modality in which an internally generated action is produced. Subjects were asked to read either silently or aloud, items from a list of words. After a delay of 5 min, they were required to indicate in a new list which words had been read previously (either silently or overtly), or had never been presented during the reading task. With respect to normal controls, schizophrenic patients showed a significant bias to report that they had read aloud words which they had actually read silently, or which were absent during the reading task. The results are discussed in relation to recent neuroimaging studies on inner and overt speech in hallucinating schizophrenic patients. Our data favour the hypothesis that the inability to correctly discriminate between inner and overt speech may play a role in the onset of schizophrenic hallucinations.

Beyond consciousness of external reality: a "who" system for consciousness of action and self-consciousness

This paper offers a framework for consciousness of internal reality. Recent PET experiments are reviewed, showing partial overlap of cortical activation during self-produced actions and actions observed from other people. This overlap suggests that representations for actions may be shared by several individuals, a situation which creates a potential problem for correctly attributing an action to its agent. The neural conditions for correct agency judgments are thus assigned a key role in self/other distinction and self-consciousness. A series of behavioral experiments that demonstrate, in normal subjects, the poor monitoring of action-related signals and the difficulty in recognizing self-produced actions are described. In patients presenting delusions, this difficulty dramatically increases and actions become systematically misattributed. These results point to schizophrenia and related disorders as a paradigmatic alteration of a "Who?" system for self-consciousness.

Lateral asymmetries in auditory acuity distinguish hallucinating from nonhallucinating schizophrenic patients

Bilateral absolute auditory thresholds for frequencies ranging from 250 to 8000 Hz were examined on two occasions in schizophrenic patients and normal control subjects. Patients were classified as hallucinators and nonhallucinators on the basis of symptom ratings on both occasions. Previous evidence of better right than left ear acuity in schizophrenia was replicated but was found to characterize nonhallucinating patients only. Hallucinators showed no lateral asymmetry and inferior right ear acuity as compared with that in nonhallucinators. The results were reliable on retest. Brief Psychiatric Rating Scale scores of positive and negative symptoms in some cases differentiated hallucinators from nonhallucinators. The relationship of verbal hallucinations and right ear-left temporal lobe functions is discussed, together with complexities in cerebral laterality-syndrome relationships.

Towards a neuropsychology of schizophrenia

A viable neuropsychology of schizophrenia requires, first, that signs and symptoms be understood in terms of underlying psychological processes and, second, that these underlying processes be related to brain systems. We propose that the negative signs of schizophrenia reflect a defect in the initiation of spontaneous action, while the positive symptoms reflect a defect in the internal monitoring of action. The spontaneous initiation of action depends upon brain systems linking the prefrontal cortex and the basal ganglia. Internal monitoring, carried out in the hippocampus, of spontaneous action, depends upon links between the prefrontal cortex and the hippocampus via the parahippocampal cortex and the cingulate cortex.

The positive and negative symptoms of schizophrenia reflect impairments in the perception and initiation of action

The CNS maintains a fundamental distinction between actions elicited by external stimuli and actions elicited by internal goals (acts of will). As a result the intact organism can monitor centrally three aspects of its own actions: (1) the action appropriate to current external stimulation (stimulus intention or meaning); (2) the action appropriate to current goals (willed intention); and (3) the action which was actually selected (corollary discharge). In Type I (acute) schizophrenic patients, intentions of will lead to actions, but these willed intentions are not monitored correctly. This apparent discrepancy between will and action gives rise to experiential (1st rank) positive symptoms (e.g. delusions of control and passivity). In Type II (chronic) patients, intentions of will are no longer properly formed and so actions are rarely elicited via this route. This gives rise to behavioural negative signs (e.g. poverty of speech). The behaviour of Type II schizophrenics has surface similarities to that shown by patients with Parkinson's disease and patients with frontal lobe lesions in that all three types of patient show a relative deficit of actions elicited by willed intentions. Dopamine blocking drugs reduce positive symptoms in Type I patients precisely because they induce Parkinsonism, i.e. reduce the likelihood of actions being initiated by willed intentions. This in turn reduces the likelihood that actions will occur for which the patient had no awareness of his intention to act.

Vocal activity in verbal hallucinations

Vocal and forearm EMGs were recorded from 19 hallucinating and 22 nonhallucinating psychiatric inpatients. A microphone placed close to the lips was used to detect subvocal speech. The subjects' EMG and subvocal responses to pre-recorded statements were also assessed. Subjects who experienced hallucinations during assessment were asked to estimate the frequency of their hallucinations and rate phenomenological of their most recent hallucination. Results essentially replicated studies that found increased vocal potentials in hallucinators, but also showed that these increased potentials were nonsignificant when nonvocal measures are included in the statistical analysis. Subvocal speech and coincident increases in vocal EMG with reports of hallucinations, and with reports of pre-recorded statements, were not found. A significant negative correlation was found between the mean vocal potential of hallucinators and the perceived location of their most recent hallucination. The pre-recorded statements were generally perceived to be louder, clearer and more outside the head than the most recent hallucination.

Control of auditory hallucinations through occlusion of monaural auditory input

A schizophrenic patient whose severe level of auditory hallucinations had proved refractory to neuroleptic medication was given two treatment techniques derived from Green's theory that hallucinations represent verbal activity in the non-dominant hemisphere. Voice activity was markedly reduced in frequency and severity over a six-month period, and led to general improvements in interpersonal functioning. There was evidence for independent and additive effects of the two techniques.