Acoustic salience in emotional voice perception and its relationship with hallucination proneness.

Auditory verbal hallucinations (AVH) are reported in approximately 70% of psychotic patients, but they also may occur in approximately 10% of the healthy general population. AVH have been related to altered processing of vocal emotions at both sensory and higher-order processing stages in psychotic patients. However, it remains to be clarified whether individuals with high hallucination proneness (HP) exhibit a similar pattern of alterations. We investigated the impact of HP on vocal emotional perception and specified whether manipulations of acoustic cues, such as sound intensity and duration, related to salience changes, affect the time course of voice processing reflected in event-related potentials (ERP) of the electroencephalogram. Participants varying in HP performed a task involving the categorization of emotional nonverbal vocalizations (neutral, anger, and amusement) differing in duration and intensity. ERP results demonstrated interactive effects of HP, valence, and acoustic cues on both early (N1, P2) and late (Late Positive Potential [LPP]) processing stages. Higher HP was associated with decreased N1 and increased P2 amplitudes in response to louder and longer neutral (vs. positive) vocalizations, as well as with a larger LPP to louder and longer negative (vs. neutral) vocalizations. These findings suggest that HP is associated with changes in the processing of vocal emotions that might be related to altered salience of acoustic representations of emotions. Consistent with prior studies with psychotic patients, these findings show that altered perception of vocal emotions may additionally contribute to the experience of hallucinations in nonclinical samples.

Cognitive and phenomenological characteristics of hallucination-proneness across the lifespan.

INTRODUCTION: The impact of age on hallucination-proneness within healthy adult cohorts and its relation to underlying cognitive mechanisms is underexplored. Based on previously researched trends in relation to cognitive ageing, we hypothesised that older and younger adults, when compared to a middle adult age group, would show differential relations between hallucination-proneness and cognitive performance. METHODS: A mixed methods, between-groups study was conducted with 30 young adults, 26 older adults, and 27 from a "middle adulthood" group. Participants completed a source memory task, jumbled speech task, Launay-Slade hallucination scale, unusual experiences schedule, and control measures of delusion-proneness and attitudes to mental health. RESULTS: Compared to older age-groups, younger participants demonstrated better scores on the source memory task, and reported hearing more words in jumbled speech. Additionally, younger cohorts rated higher on hallucination-proneness and disclosed more unusual experiences on a customised schedule designed to gather further qualitative data. Jumbled speech scores positively correlated with hallucination-proneness scores, particularly for the "middle" age group. Source memory performance unexpectedly correlated positively with hallucination-proneness, although this may be the product of age differences in task performance. CONCLUSIONS: Age differences in hallucination-proneness are evident on self-report and cognitive measures. Implications are discussed for potentially non-overlapping cognitive mechanisms underlying hallucination-proneness in non-clinical groups.

Predicting hallucination proneness based on mindfulness in university students: the mediating role of mental distress.

As a risk factor of hallucination proneness, the level of mindfulness has not yet been investigated in non-clinical participants. Other potential mediators, such as mental distress (depression, anxiety, and stress) which contribute to hallucination proneness also need to be assessed. This study investigated the mediating effect of mental distress in predicting hallucination proneness based on mindfulness. A number of 168 Iranian university students completed three questionnaires: (1) the five-facet mindfulness questionnaire, (2) the depression, anxiety and stress scale; and (3) the revised hallucination scale. The results showed that there was a significant association between levels of mindfulness and hallucination proneness. Mental distress has a significant effect on four facets of mindfulness questionnaire and an insignificant effect on one facet (awareness) in predicting hallucination. These effects were both direct and indirect. The indirect effect was developed by the mediating role of mental distress.

I Am There but Not Quite: An Unfaithful Mirror That Reduces Feelings of Ownership and Agency.

The experience of seeing one's own face in a mirror is a common experience in daily life. Visual feedback from a mirror is linked to a sense of identity. We developed a procedure that allowed individuals to watch their own face, as in a normal mirror, or with specific distortions (lag) for active movement or passive touch. By distorting visual feedback while the face is being observed on a screen, we document an illusion of reduced embodiment. Participants made mouth movements, while their forehead was touched with a pen. Visual feedback was either synchronous (simultaneous) with reality, as in a mirror, or asynchronous (delayed). Asynchronous feedback was exclusive to touch or movement in different conditions and incorporated both in a third condition. Following stimulation, participants rated their perception of the face in the mirror, and perception of their own face, on questions that tapped into agency and ownership. Results showed that perceptions of both agency and ownership were affected by asynchrony. Effects related to agency, in particular, were moderated by individual differences in depersonalisation and auditory hallucination-proneness, variables with theoretical links to embodiment. The illusion presents a new way of investigating the extent to which body representations are malleable.

Unusual sleep experiences and dissociation as mediators between sleep quality and proneness to hallucinations in a nonclinical population sample: a preliminary study.

INTRODUCTION: The purpose of this study was to examine the relationship of sleep quality to proneness to hallucinations and the mediating role of dissociation and unusual sleep experiences in a nonclinical sample. METHODS: One hundred and seventy-seven participants completed a questionnaire on sleep quality, a dissociative experiences scale, an unusual sleep experiences scale and a hallucination proneness scale. RESULTS: The results showed a significant positive association between quality of sleep and hallucination proneness, dissociation and unusual sleep experiences, and that dissociation and unusual sleep experiences fully mediated between sleep quality and hallucination proneness. CONCLUSIONS: Our study highlights the importance of variables related to sleep quality and unusual sleep experiences and dissociation in understanding hallucinations, and the importance of taking these variables into consideration in designing intervention directed at reducing distress caused by hallucinations.

Suggestibility and signal detection performance in hallucination-prone students.

INTRODUCTION: Auditory hallucinations are associated with signal detection biases. We examine the extent to which suggestions influence performance on a signal detection task (SDT) in highly hallucination-prone and low hallucination-prone students. We also explore the relationship between trait suggestibility, dissociation and hallucination proneness. METHOD: In two experiments, students completed on-line measures of hallucination proneness (the revised Launay-Slade Hallucination Scale; LSHS-R), trait suggestibility (Inventory of Suggestibility) and dissociation (Dissociative Experiences Scale-II). Students in the upper and lower tertiles of the LSHS-R performed an auditory SDT. Prior to the task, suggestions were made pertaining to the number of expected targets (Experiment 1, N = 60: high vs. low suggestions; Experiment 2, N = 62, no suggestion vs. high suggestion vs. no voice suggestion). RESULTS: Correlational and regression analyses indicated that trait suggestibility and dissociation predicted hallucination proneness. Highly hallucination-prone students showed a higher SDT bias in both studies. In Experiment 1, both bias scores were significantly affected by suggestions to the same degree. In Experiment 2, highly hallucination-prone students were more reactive to the high suggestion condition than the controls. CONCLUSION: Suggestions may affect source-monitoring judgments, and this effect may be greater in those who have a predisposition towards hallucinatory experiences.

Dissociation mediates the relationship between childhood maltreatment and subclinical psychosis.

More than a third of the population report childhood adversity, and these experiences are associated with an increased risk of clinical and subclinical psychosis. The reason why some people go on to develop mental health problems and others do not is a key question for study. It has been hypothesized that dissociative processes mediate the relationship between early adversity and psychosis. The current study assessed whether dissociation, and specifically depersonalization (one component of dissociation), plays a mediating role in the relationship between childhood maltreatment and both hallucination proneness and delusional ideation. The study used a cross-sectional design and recruited a student sample to assess these relationships in a nonclinical group. Dissociation mediated the relationship between early maltreatment and both hallucination proneness and delusional ideation. In terms of specific dissociative processes, depersonalization did not mediate hallucination proneness or delusional ideation. Absorption mediated hallucination proneness; dissociative amnesia (negatively) and absorption mediated delusional ideation. It is likely that dissociation interferes with the encoding of traumatic information in nonclinical as well as clinical groups and in certain ways. Absorption may be particularly relevant. For some people, traumatic memories may intrude into conscious awareness in adulthood as psychotic-type experience.

Psychotic-Like Experiences and Psychological Distress: The Role of Resilience.

BACKGROUND: The occurrence of psychotic-like experiences and schizotypal features in the general nonclinical population may imply a connection with psychosis-related liability. OBJECTIVE: This study was designed to examine the role of resilience in the relationship of hallucination and delusion-like experiences and schizotypal features to psychological distress in a nonclinical sample. DESIGN: The study sample (n = 432 university students) was selected through a stratified cluster sampling procedure, and measures of hallucination proneness, delusion proneness, schizotypal personality, and psychological distress were administered. RESULTS: While all three indices of psychotic-like experiences correlated with one another, only hallucination proneness and schizotypal personality features correlated with psychological distress and only schizotypal traits correlated with resilience. Schizotypy was found to have an indirect effect on distress through resilience. CONCLUSIONS: Findings imply the possibility of two types of schizotypy, with high or low resilience. It appears that schizotypes with low resilience may be susceptible to adversity and mental disorders, while high resilience may be protective.

Ambiguity between self and other: Individual differences in action attribution.

Individuals differ in their ability to attribute actions to self or other. This variance is thought to explain, in part, the experience of voice-hearing. Misattribution can also be context-driven. For example, causal ambiguity can arise when the actions of two or more individuals are coordinated and produce similar effects (e.g., music-making). Experience in such challenging contexts may refine skills of action attribution. Forty participants completed a novel finger-tapping task which parametrically manipulated the proportion of control that 'self' versus 'other' possessed over resulting auditory tones. Results showed that action misattribution peaked in the middle of the self-to-other continuum and was biased towards other. This pattern was related to both high hallucination-proneness and to low musical-experience. Findings suggest not only that causal ambiguity plays a key role in agency but also that action attribution abilities may improve with practice, potentially providing an avenue for remediation of the positive symptoms of schizophrenia.

Associations between intrusive thoughts, reality discrimination and hallucination-proneness in healthy young adults.

INTRODUCTION: People who experience intrusive thoughts are at increased risk of developing hallucinatory experiences, as are people who have weak reality discrimination skills. No study has yet examined whether these two factors interact to make a person especially prone to hallucinatory experiences. The present study examined this question in a non-clinical sample. METHODS: Participants were 160 students, who completed a reality discrimination task, as well as self-report measures of cannabis use, negative affect, intrusive thoughts and auditory hallucination-proneness. The possibility of an interaction between reality discrimination performance and level of intrusive thoughts was assessed using multiple regression. RESULTS: The number of reality discrimination errors and level of intrusive thoughts were independent predictors of hallucination-proneness. The reality discrimination errors × intrusive thoughts interaction term was significant, with participants who made many reality discrimination errors and reported high levels of intrusive thoughts being especially prone to hallucinatory experiences. CONCLUSIONS: Hallucinatory experiences are more likely to occur in people who report high levels of intrusive thoughts and have weak reality discrimination skills. If applicable to clinical samples, these findings suggest that improving patients' reality discrimination skills and reducing the number of intrusive thoughts they experience may reduce the frequency of hallucinatory experiences.

Revisiting alpha resting state dynamics underlying hallucinatory vulnerability: Insights from Hidden semi-Markov Modeling.

BACKGROUND: Resting state (RS) brain activity is inherently non-stationary. Hidden semi-Markov Models (HsMM) can characterize continuous RS data as a sequence of recurring and distinct brain states along with their spatio-temporal dynamics. NEW METHOD: Recent explorations suggest that HsMM state dynamics in the alpha frequency band link to auditory hallucination proneness (HP) in non-clinical individuals. The present study aimed to replicate these findings to elucidate robust neural correlates of hallucinatory vulnerability. Specifically, we aimed to investigate the reproducibility of HsMM states across different data sets and within-data set variants as well as the replicability of the association between alpha brain state dynamics and HP. RESULTS: We found that most brain states are reproducible in different data sets, confirming that the HsMM characterized robust and generalizable EEG RS dynamics on a sub-second timescale. Brain state topographies and temporal dynamics of different within-data set variants showed substantial similarities and were robust against reduced data length and number of electrodes. However, the association with HP was not directly reproducible across data sets. COMPARISON WITH EXISTING METHODS: The HsMM optimally leverages the high temporal resolution of EEG data and overcomes time-domain restrictions of other state allocation methods. CONCLUSION: The results indicate that the sensitivity of brain state dynamics to capture individual variability in HP may depend on the data recording characteristics and individual variability in RS cognition, such as mind wandering. Future studies should consider that the order in which eyes-open and eyes-closed RS data are acquired directly influences an individual's attentional state and generation of spontaneous thoughts, and thereby might mediate the link to hallucinatory vulnerability.

Hypersensitivity to passive voice hearing in hallucination proneness.

Voices are a complex and rich acoustic signal processed in an extensive cortical brain network. Specialized regions within this network support voice perception and production and may be differentially affected in pathological voice processing. For example, the experience of hallucinating voices has been linked to hyperactivity in temporal and extra-temporal voice areas, possibly extending into regions associated with vocalization. Predominant self-monitoring hypotheses ascribe a primary role of voice production regions to auditory verbal hallucinations (AVH). Alternative postulations view a generalized perceptual salience bias as causal to AVH. These theories are not mutually exclusive as both ascribe the emergence and phenomenology of AVH to unbalanced top-down and bottom-up signal processing. The focus of the current study was to investigate the neurocognitive mechanisms underlying predisposition brain states for emergent hallucinations, detached from the effects of inner speech. Using the temporal voice area (TVA) localizer task, we explored putative hypersalient responses to passively presented sounds in relation to hallucination proneness (HP). Furthermore, to avoid confounds commonly found in in clinical samples, we employed the Launay-Slade Hallucination Scale (LSHS) for the quantification of HP levels in healthy people across an experiential continuum spanning the general population. We report increased activation in the right posterior superior temporal gyrus (pSTG) during the perception of voice features that positively correlates with increased HP scores. In line with prior results, we propose that this right-lateralized pSTG activation might indicate early hypersensitivity to acoustic features coding speaker identity that extends beyond own voice production to perception in healthy participants prone to experience AVH.

Attention to voices is increased in non-clinical auditory verbal hallucinations irrespective of salience.

Alterations in the processing of vocal emotions have been associated with both clinical and non-clinical auditory verbal hallucinations (AVH), suggesting that changes in the mechanisms underpinning voice perception contribute to AVH. These alterations seem to be more pronounced in psychotic patients with AVH when attention demands increase. However, it remains to be clarified how attention modulates the processing of vocal emotions in individuals without clinical diagnoses who report hearing voices but no related distress. Using an active auditory oddball task, the current study clarified how emotion and attention interact during voice processing as a function of AVH proneness, and examined the contributions of stimulus valence and intensity. Participants with vs. without non-clinical AVH were presented with target vocalizations differing in valence (neutral; positive; negative) and intensity (55 decibels (dB); 75 dB). The P3b amplitude was larger in response to louder (vs. softer) vocal targets irrespective of valence, and in response to negative (vs. neutral) vocal targets irrespective of intensity. Of note, the P3b amplitude was globally increased in response to vocal targets in participants reporting AVH, and failed to be modulated by valence and intensity in these participants. These findings suggest enhanced voluntary attention to changes in vocal expressions but reduced discrimination of salient and non-salient cues. A decreased sensitivity to salience cues of vocalizations could contribute to increased cognitive control demands, setting the stage for an AVH.

Imaginary Companions, Inner Speech, and Auditory Verbal Hallucinations: What Are the Relations?

Interacting with imaginary companions (ICs) is now considered a natural part of childhood for many children, and has been associated with a range of positive developmental outcomes. Recent research has explored how the phenomenon of ICs in childhood and adulthood relates to the more unusual experience of hearing voices (or auditory verbal hallucinations, AVH). Specifically, parallels have been drawn between the varied phenomenology of the two kinds of experience, including the issues of quasi-perceptual vividness and autonomy/control. One line of research has explored how ICs might arise through the internalization of linguistically mediated social exchanges to form dialogic inner speech. We present data from two studies on the relation between ICs in childhood and adulthood and the experience of inner speech. In the first, a large community sample of adults (N = 1,472) completed online the new Varieties of Inner Speech - Revised (VISQ-R) questionnaire (Alderson-Day et al., 2018) on the phenomenology of inner speech, in addition to providing data on ICs and AVH. The results showed differences in inner speech phenomenology in individuals with a history of ICs, with higher scores on the Dialogic, Evaluative, and Other Voices subscales of the VISQ-R. In the second study, a smaller community sample of adults (N = 48) completed an auditory signal detection task as well as providing data on ICs and AVH. In addition to scoring higher on AVH proneness, individuals with a history of ICs showed reduced sensitivity to detecting speech in white noise as well as a bias toward detecting it. The latter finding mirrored a pattern previously found in both clinical and nonclinical individuals with AVH. These findings are consistent with the view that ICs represent a hallucination-like experience in childhood and adulthood which shows meaningful developmental relations with the experience of inner speech.

Dysfunctional meta-cognitive beliefs mediate the relation between temperament traits and hallucination-proneness in non-clinical population.

We investigated whether dysfunctional metacognitive beliefs (negative beliefs about uncontrollability and danger of thoughts) mediate the relationship between temperamental characteristics of behavior and hallucinatory-like experiences in healthy subjects (n=137). Our analyses showed that four temperamental traits (emotional reactivity, perseveration, endurance and briskness) were mediated by negative beliefs about uncontrollability and danger of thoughts in relation to hallucination proneness. Our research tentatively suggests that temperament affects hallucination proneness via metacognition.

Relation between jumping to conclusions and cognitive functioning in people with schizophrenia in contrast with healthy participants.

'Jumping to conclusions' (JTC) is a reasoning bias consisting of a tendency to take a decision without having enough information about an event. It has been related to the presence of delusions. The aim of the present study was to assess the relationship between three tasks differing in complexity and concept which assess JTC and cognitive functioning in a sample of people with schizophrenia and healthy participants. We also assessed which cognitive variables, after controlling for psychotic symptoms, explained the presence of JTC in each sample. A total of 43 patients with schizophrenia and 57 healthy participants were assessed with a cognition battery including executive function, verbal memory, and IQ. JTC was assessed with three tasks (probability of 85:15; 60:40, and 60:40 with emotional component). Patients were also assessed on psychotic and affective symptoms and the healthy participants on proneness to hallucinations and delusion. The present study demonstrates a clear relationship between JTC and cognitive functioning, especially in working memory, verbal memory, and cognitive processing speed in people with schizophrenia and in healthy participants. However no relationship was found in the emotional task of JTC. Hallucinations (in people with schizophrenia) and proneness to hallucinations (in the healthy participants) are related to JTC. Our results suggest that diverse psychological interventions such as cognitive remediation, cognitive behavioral therapy and meta-cognitive training might contribute to reducing JTC bias.