Auditory Verbal Hallucinations Research Articles

Feasibility and Efficacy of Virtual Reality Interventions to Improve Psychosocial Functioning in Psychosis: Systematic Review.

BackgroundFunctional recovery in psychosis remains a challenge despite current evidence-based treatment approaches. To address this problem, innovative interventions using virtual reality (VR) have recently been developed. VR technologies have enabled the development of realistic environments in which individuals with psychosis can receive psychosocial treatment interventions in more ecological settings than traditional clinics. These interventions may therefore increase the transfer of learned psychosocial skills to real-world environments, thereby promoting long-term functional recovery. However, the overall feasibility and efficacy of such interventions within the psychosis population remain unclear.ObjectiveThis systematic review aims to investigate whether VR-based psychosocial interventions are feasible and enjoyable for individuals with psychosis, synthesize current evidence on the efficacy of VR-based psychosocial interventions for psychosis, and identify the limitations in the current literature to guide future research.MethodsThis research followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Literature searches were conducted in PubMed and PsycINFO in May 2021. We searched for peer-reviewed English articles that used a psychosocial intervention with a VR component. Participants in the included studies were diagnosed with schizophrenia, schizoaffective disorder, or another psychotic disorder. The included studies were divided into four categories as follows: cognitive remediation interventions, social skills interventions, vocational skills interventions, and auditory verbal hallucinations and paranoia interventions. The risk of bias assessment was performed for each study.ResultsA total of 18 studies were included in this systematic review. Of these 18 studies, 4 (22%) studies used a cognitive remediation intervention, 4 (22%) studies used a social skills intervention, 3 (17%) studies used a vocational skills intervention, and 7 (39%) studies implemented an intervention aimed at improving auditory verbal hallucinations or paranoia. A total of 745 individuals with psychosis were included in the study. All the studies that evaluated feasibility showed that VR-based psychosocial interventions were feasible and enjoyable for individuals with psychosis. The preliminary evidence on efficacy included in this review suggests that VR-based psychosocial interventions can improve cognitive, social, and vocational skills in individuals with psychosis. VR-based interventions may also improve the symptoms of auditory verbal hallucinations and paranoia. The skills that participants learned through these interventions were durable, transferred into real-world environments, and led to improved functional outcomes, such as autonomy, managing housework, and work performance.ConclusionsVR-based interventions may represent a novel and efficacious approach for improving psychosocial functioning in psychosis. Therefore, VR-based psychosocial interventions represent a promising adjunctive therapy for the treatment of psychosis, which may be used to improve psychosocial skills, community functioning, and quality of life.

From core schemas about the self and others to voice phenomenology: Anxiety and depression affect voice hearers differently.

ObjectivesAuditory verbal hallucinations (AVHs) occur as a symptom in various mental disorders, and show different phenomenological aspects, depending on their underlying psychopathology. Anxiety and depression, which are known to be involved in the development of AVHs, are suggested to amplify a vicious cycle in which negative interpretations of daily experiences feed into the formation of negative core schemas about the self and others. However, the way in which these variables interrelate is still unknown. Therefore, our aim was to determine the specific roles of anxiety and depression in the relationship between core schemas and emotional aspects of AVHs for three groups (non‐clinical voice hearers, affective voice hearers and non‐affective voice hearers).MethodsPositive and negative core schemas of the self and others were tested as predictors of emotional distress due to AVHs, examining anxiety and depression separately as potential mediators.ResultsResults showed full mediating effects of depression in non‐affective voice hearers in the relationship between negative core schemas and AVH distress, but not in affective voice hearers. Anxiety was not a mediator in any of the groups.ConclusionsThese findings suggest different emotional mechanisms depending on the underlying psychopathology.

Measuring Voluntary Control Over Hallucinations: The Yale Control Over Perceptual Experiences (COPE) Scales.

Auditory verbal hallucinations (AVH) frequently cause significant distress and dysfunction, and may be unresponsive to conventional treatments. Some voice-hearers report an ability to fully control the onset and offset of their AVH, making them significantly less disruptive. Measuring and understanding these abilities may lead to novel interventions to enhance control over AVH. Fifty-two voice-hearers participated in the pilot study. 318 participants with frequent AVH participated in the validation study. A pool of 59 items was developed by a diverse team including voice-hearers and clinicians. After the pilot study, 35 items were retained. Factorial structure was assessed with exploratory (EFA, n = 148) and confirmatory (CFA, n = 170) factor analyses. Reliability and convergent validity were assessed using a comprehensive battery of validated phenomenological and clinical scales. CFA on the final 18 items supported two factors for a Methods of Control Scale (5 items each, average ω = .87), and one factor for a Degree of Control Scale (8 items, average ω = .95). Correlation with clinical measures supported convergent validity. Degree of control was associated with positive clinical outcomes in voice-hearers both with and without a psychosis-spectrum diagnosis. Degree of control also varied with quality of life independently of symptom severity and AVH content. The Yale control over perceptual experiences (COPE) Scales robustly measure voice-hearers' control over AVH and exhibit sound psychometric properties. Results demonstrate that the capacity to voluntarily control AVH is independently associated with positive clinical outcomes. Reliable measurement of control over AVH will enable future development of interventions meant to bolster that control.

Fully automated detection of formal thought disorder with Time-series Augmented Representations for Detection of Incoherent Speech (TARDIS)

Formal thought disorder (ThD) is a clinical sign of schizophrenia amongst other serious mental health conditions. ThD can be recognized by observing incoherent speech - speech in which it is difficult to perceive connections between successive utterances and lacks a clear global theme. Automated assessment of the coherence of speech in patients with schizophrenia has been an active area of research for over a decade, in an effort to develop an objective and reliable instrument through which to quantify ThD. However, this work has largely been conducted in controlled settings using structured interviews and depended upon manual transcription services to render audio recordings amenable to computational analysis. In this paper, we present an evaluation of such automated methods in the context of a fully automated system using Automated Speech Recognition (ASR) in place of a manual transcription service, with “audio diaries” collected in naturalistic settings from participants experiencing Auditory Verbal Hallucinations (AVH). We show that performance lost due to ASR errors can often be restored through the application of Time-Series Augmented Representations for Detection of Incoherent Speech (TARDIS), a novel approach that involves treating the sequence of coherence scores from a transcript as a time-series, providing features for machine learning. With ASR, TARDIS improves average AUC across coherence metrics for detection of severe ThD by 0.09; average correlation with human-labeled derailment scores by 0.10; and average correlation between coherence estimates from manual and ASR-derived transcripts by 0.29. In addition, TARDIS improves the agreement between coherence estimates from manual transcripts and human judgment and correlation with self-reported estimates of AVH symptom severity. As such, TARDIS eliminates a fundamental barrier to the deployment of automated methods to detect linguistic indicators of ThD to monitor and improve clinical care in serious mental illness.

Continuities and Discontinuities in the Cognitive Mechanisms Associated With Clinical and Nonclinical Auditory Verbal Hallucinations.

Auditory verbal hallucinations (AVHs) are typically associated with schizophrenia but also occur in individuals without any need for care (nonclinical voice hearers [NCVHs]). Cognitive models of AVHs posit potential biases in source monitoring, top-down processes, or a failure to inhibit intrusive memories. However, research across clinical/nonclinical groups is limited, and the extent to which there may be continuity in cognitive mechanism across groups, as predicted by the psychosis-continuum hypothesis, is unclear. We report two studies in which voice hearers with psychosis (n = 31) and NCVH participants reporting regular spiritual voices (n = 26) completed a battery of cognitive tasks. Compared with non-voice-hearing groups (ns = 33 and 28), voice hearers with psychosis showed atypical performance on signal detection, dichotic listening, and memory-inhibition tasks but intact performance on the source-monitoring task. NCVH participants, however, showed only atypical signal detection, which suggests differences between clinical and nonclinical voice hearers potentially related to attentional control and inhibition. These findings suggest that at the level of cognition, continuum models of hallucinations may need to take into account continuity but also discontinuity between clinical and nonclinical groups.

Low-frequency rTMS treatment alters the topographical organization of functional brain networks in schizophrenia patients with auditory verbal hallucination

Auditory verbal hallucinations (AVH) are an important characteristic of schizophrenia. Repeated transcranial magnetic stimulation (rTMS) has been evidence to be effective in treating AVH. We evaluated the topological properties of resting-state functional brain networks in schizophrenia patients with AVH (n = 32) who received 1-Hz rTMS treatment and matched healthy controls (n = 33). The results showed that the psychotic symptoms and certain neurocognitive performances in patients were improved by rTMS treatment. Furthermore, the pretreatment patients showed abnormal global topological metrics compared with the controls, including lower global efficiency (Eglob, represents the relative quality of information transmission between all nodes in the network) and higher characteristic path length (Lp, characterizes the mean shortest distance between any two nodes in the network). The pretreament patients also showed decreased local topological metrics relative to the controls, including the nodal shortest path (NLp, quantifies the mean distance between the given node and the other nodes in the network) and nodal efficiency (Ne, measures the information interchange among the neighbor nodes when one node is removed), mainly located in the prefrontal cortex, occipital cortex, and subcortical regions. While the abnormal global and local topological patterns were normalized in patients after rTMS treatment. The multiple linear regression analysis indicated that the baseline topological metrics could be associated with the clinical responses after treatment in the patient group. The results suggested that the topological organization of the functional brain network was globally and regionally altered in schizophrenia patients with AVH after rTMS treatment and may be a potential therapeutic effect for AVH in schizophrenia.

Altered Effective Brain Connectivity During Habituation in First Episode Schizophrenia With Auditory Verbal Hallucinations: A Dichotic Listening EEG Study.

Background: Habituation is considered to have protective and filtering mechanisms. The present study is aim to find the casual relationship and mechanisms of excitatory–inhibitory (E/I) dysfunctions in schizophrenia (SCZ) via habituation.Methods: A dichotic listening paradigm was performed with simultaneous EEG recording on 22 schizophrenia patients and 22 gender- and age-matched healthy controls. Source reconstruction and dynamic causal modeling (DCM) analysis were performed to estimate the effective connectivity and casual relationship between frontal and temporal regions before and after habituation.Results: The schizophrenia patients expressed later habituation onset (p < 0.01) and hyper-activity in both lateral frontal–temporal cortices than controls (p = 0.001). The patients also showed decreased top-down and bottom-up connectivity in bilateral frontal–temporal regions (p < 0.01). The contralateral frontal–frontal and temporal–temporal connectivity showed a left to right decreasing (p < 0.01) and right to left strengthening (p < 0.01).Conclusions: The results give causal evidence for E/I imbalance in schizophrenia during dichotic auditory processing. The altered effective connectivity in frontal–temporal circuit could represent the trait bio-marker of schizophrenia with auditory hallucinations.

Processing of linguistic deixis in people with schizophrenia, with and without auditory verbal hallucinations

Auditory verbal hallucinations (AVH) are a key symptom of schizophrenia (SZ) defined by anomalous perception of speech. Anomalies of processing external speech stimuli have also been reported in people with AVH, but it is unexplored which specific dimensions of language are processed differently. Using a speech perception task (passive listening), we here targeted the processing of deixis, a key dimension of language governing the contextual anchoring of speech in interpersonal context. We designed naturalistic speech stimuli that were either non-personal and fact-reporting (‘low-deixis’ condition), or else involved rich deictic devices such as the grammatical first and second persons, direct questions, and vocatives (‘high-deixis’). We asked whether neural correlates of deixis obtained with fMRI would distinguish patients with and without frequent hallucinations (AVH + vs AVH−) from controls and each other. Results showed that high-deixis relative to low-deixis was associated with clusters of increased activation in the bilateral middle temporal gyri extending into the temporal poles and the inferior parietal cortex, in all groups. The AVH + and AVH− groups did not differ. When unifying them, the SZ group as a whole showed altered activity in the precuneus, midline regions and inferior parietal cortex. These results fail to confirm deictic processing anomalies specific to patients with AVH, but reveal such anomalies across SZ. Hypoactivation of this network may relate to a cognitive mechanism for attributing and anchoring thought and referential speech content in context.

Prof K C Dube Poster Award

Background:Auditory verbal hallucinations (AVH) are one of the core features of schizophrenia. In approximately 25% of patients with schizophrenia, AVH are refractory to psychotropic drug treatment and can chronically persist. Superior temporal cortex is implicated in AVH. Continuous Theta Burst Stimulation (cTBS) can be one of the add on treatment for auditory hallucination in refractory cases. Accelerated cTBS protocols have the advantage of shorter application time and lower stimulation intensity. In addition use of robotized neuronavigation will improve the accuracy of coil placement and thus localization of the stimulation site.Aim:We aimed to evaluate the efficacy of accelerated cTBS over left superior temporal cortex (STC) in improvement of AVH in schizophrenia, using neuronavigation and robotic arm.Methods:40 patients of schizophrenia with AVH, were enrolled for this randomized, sham controlled, double-blind trial. Each participant in the active group received cTBS comprising of 900 pulses (bursts of 3 stimuli at 50 Hz repeated at 5 Hz frequency), twice a day for 5 days per week for 3 consecutive weeks. AVH were assessed with PSYRATS(AHRS), PANSS & CGI. Assessments were carried out at baseline,1st,3rd & 6th weeks.Results:The improvement in AVH in active group at 1st 3rd & 6th week was not statistically significant at 0.05 (p-value) as compared to sham group. Stimulation was well tolerated.Conclusion:Results suggest that accelerated robotized neuronavigated cTBS does not appear to have substantial potential in the treatment of auditory hallucinations and further research should investigate individualised MRI guided neuronavigation with higher sample size.

Cingulum bundle integrity in schizophrenia with auditory verbal hallucinations: A diffusion tensor imaging tractographic study.

Cingulum bundle (CB) is frequently implicated in schizophrenia; however, its role in specific symptoms of schizophrenia such as auditory verbal hallucinations (AVHs) is less explored. Few studies have reported association between reduced integrity of CB and severity of AVH. Using a symptom-based approach, this diffusion tensor imaging (DTI) tractographic study was aimed to assess and compare the integrity of CB in schizophrenia with AVH, schizophrenia without AVH and healthy controls. A total of 92 right-handed adult individuals (aged 18-50 yr) were recruited across three study groups. Those with Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) diagnosis of schizophrenia with AVH (group I; n=30) were compared to those with DSM-5 schizophrenia without lifetime AVH (group II; n=32) and healthy controls (group III; n=30; screened using Mini International Neuropsychiatric Interview version-7.0.0. and negative family history). Clinical assessments (groups I and II) included scale for assessment of positive symptoms, scale for assessment of negative symptoms, clinical global impression-schizophrenia and psychotic symptom rating scale. All participants underwent DTI, and quantitative tract-based measurements of fractional anisotropy (FA) were obtained for images using DTI studio version-3.0. All groups were comparable for age, gender, education and severity of illness. Group I had significantly lower FA values in the cingulate gyrus (CG) part of the left CB compared to groups II and III. No significant difference was found between groups II and III. The findings of this study suggest that the disruption in the left CB appears to be specific for AVH-positive schizophrenia. The finding is, however, preliminary subject to replication in future studies. Further investigations are needed to understand its relevance in the context of AVH-positive schizophrenia.

BPSS Award

Trans-cranial magnetic stimulation (TMS) can noninvasively modulate specific brain regions to dissipate auditory verbal hallucinations (AVH) in schizophrenia. Citing critical involvement of temporoparietal cortex (TPC) in AVH, we aimed to study the effect of continuous theta burst stimulation (cTBS) targeting bilateral TPC in schizophrenia subjects with AVH, on a randomized rater blinded placebo control trial. 59 patients were randomly allocated to active and sham groups. They received 20 cTBS sessions (2 per day: first right TPC, then left TPC) 5 days a week for 2 weeks. PANSS (Positive and Negative Syndrome Scale), AVHRS (Auditory vocal hallucination rating scale), PSYRAT-AH (Psychiatric symptoms rating scale- Auditory hallucinations scale), CDSS (Calgary depression scale for schizophrenia), SCoRS (Schizophrenia cognition rating scale), CGI-S (Clinical global impression-severity) were assessed at baseline, immediately post 20th session and 2 weeks post-TBS. 50 patients (25-active, 25-sham) completed the study. Conducting an intention to treat analysis, we found a significant group*time effect for PANSS, AVHRS, PSYRAT-AH, CDSS, SCoRS, CGI-S but when controlled for confounding variables, only PANSS-PS (F=26.617, p<0.001), PANSS-TOTAL (F=23.671, p<0.001), AVHRS (F=17.779, p<0.001), PSYRAT-AH (F=11.385, p<0.001) and CGI-S (F=28.462, p<0.001) retained significance. We conclude that cTBS over TPC is safe and has efficacy in AVH in schizophrenia.

A Study of Fractional Amplitude of Low Frequency Fluctuation in Schizophrenia Patients with Persistent Verbal Auditory Hallucinations

Background： Auditory verbal hallucinations (AVHs), one of the hallmark positive symptoms of schizophrenia (SCZ), affect 60-80% of SCZ patients. However, the neuroimaging mechanisms underlying AVHs, particularly persistent AVHs, are currently unknown. The aim of this study was to explore the neuroimaging mechanisms of persistent AVHs by comparing the characteristics of changes in fractional amplitude of low frequency fluctuations (fALFF) values of subjects. Methods： 64 SCZ patients with persistent AVHs, 39 patients with non-AVHs, and 60 healthy controls (HC) underwent a resting-state functional magnetic resonance imaging (MRI) study. The fALFF was used to assess localized spontaneous neural activity in the brain of three groups of subjects. The Positive and Negative Symptoms scale (PANSS) was used to rate the severity of patients' psychiatric symptoms; the P3 item on the PANSS scale was used to assess the severity of persistent AVHs. Results： SCZ patients with persistent AVHs had lower fALFF values in the right lingual gyrus, right postcentral, and left supplementary movement area (SMA) than in the HC, and higher fALFF values in the right medial superior frontal, left inferior parietal lobule, left precuneus, and right supramarginal than in the HC. SCZ patients with non-AVHs had lower fALFF values in the left lingual gyrus, right postcentral, and left supplementary motor area than in the HC group, while higher fALFF values were found in the right medial superior frontal only. However, there was no difference in fALFF values between patients with persistent AVHs and non-AVH patients. Conclusions： These results suggest that local spontaneous neural activity was significantly impaired in the brains of patients in the AVH and non-AVH groups compared to those in HC, and that altering spontaneous neural activity in these brain regions may be of value in the treatment of SCZ.

Нейрокогнитивные модели вербальных галлюцинаций при шизофрении: обзор

Recent studies at the interface between psychiatry and neuroscience demonstrate a trend towards the investigation of single significant clinical characteristics of mental disorders in contrast to the analysis of a mental disorder as a homogeneous nosological unit. Thus, a large body of studies is focused on auditory verbal hallucinations (AVH) in schizophrenia, which are one of the core positive symptoms of the disorder and an important diagnostic criterion. Nevertheless, the neuropsychological and neurophysiological mechanisms of AVH in patients with schizophrenia remain debatable. In this paper, we will review the main neurocognitive models of AVH in schizophrenia, including models of intrusive cognitions and poor inhibitory control, a model of attentional shift to inner auditory stimuli and an inability to reallocate its resources, a model of expectation maximization, a model of working memory deficit, a model of poor source-monitoring, models of AVH within cultural-historical approach, and a model of impaired verbal self-monitoring in inner speech. The results of several neuroimaging and neurophysiological studies relevant to the models are also highlighted. We conclude that schizophrenia patients with AVH demonstrate deficits in executive functions and language, or rather a poor cross-functional interaction between them.

Speech processing in voice-hearers: Bridging the gap between empirical research and clinical implications.

Individuals who hear voices (i.e. auditory verbal hallucinations) have been reported to exhibit a range of difficulties when listening to and processing the speech of other people. These speech processing challenges are observed even in the absence of hearing voices; however, some appear to be exacerbated during periods of acute symptomology. In this advisory piece, key findings from pertinent empirical research into external speech processing in voice-hearers are presented with the intention of informing healthcare professionals. It is the view that through a better understanding of the speech processing deficits faced by individuals who hear voices, more effective communication with such patients can be had.

Negative valence of hallucinatory voices as predictor of cortical glutamatergic metabolite levels in schizophrenia patients.

ObjectivesNegative emotional valence of auditory verbal hallucinations (AVHs) in schizophrenia can be a source of distress and is considered a strong predictor of illness severity. Previous studies have found glutamate to mediate AVH severity in frontal and temporal brain regions, however, they do not specifically address emotional valence of AVH. The role of glutamate for the experience of negative‐ versus positive emotional valence of AVH is therefore unknown and was investigated in the current study.MethodsUsing magnetic resonance spectroscopy (MRS), 37 schizophrenia patients had Glx (glutamate+glutamine) measured in the left superior temporal gyrus (STG), and additionally in the anterior cingulate cortex (ACC) and the right STG, or in the left inferior frontal gyrus (IFG). Self‐reported emotional valence in AVH was measured with the Beliefs About Voices Questionnaire (BAVQ‐R).ResultsResults from linear mixed models showed that negative emotional valence was associated with reduced Glx levels across all four measured brain regions in the frontal and temporal lobe. More specifically, voices that were experienced to be omnipotent (p = 0.04) and that the patients attempted to resist (p = 0.04) were related to lower Glx levels. Follow‐up analysis of the latter showed that voices that evoked emotional resistance (i.e., fear, sadness, anger), rather than behavioral resistance, was a significant predictor of reduced glutamate (p = 0.02).ConclusionThe findings could indicate aberrant glutamatergic signaling, or increased NMDA‐receptor hypoactivity in patients who experience their voices to be more emotionally negative. Overall, the study provides support for the glutamate hypothesis of schizophrenia.

Altered Visuospatial Processing in Schizophrenia: An Event-related Potential Microstate Analysis Comparing Patients with and without Hallucinations with Healthy Controls

Patients with schizophrenia present with various symptoms related to different domains. Abnormalities of auditory and visual perception are parts of a more general problem. Nevertheless, the relationship between the lifetime history of auditory verbal hallucination (AVH), one of the most prevalent symptoms in schizophrenia, and visuospatial deficits remains unclear. This study aimed to investigate differences in hemispheric involvement and visuospatial processing between healthy controls (HCs) and schizophrenia patients with and without AVHs. HCs (N = 20), schizophrenia patients with AVH (AVH group, N = 16), and schizophrenia patients without hallucinations (NH group, N = 10) participated in a 4-choice reaction task with lateralized stimuli. An event-related potential (ERP)-microstate approach was used to analyze ERP differences between the conditions and groups. The schizophrenia patients without hallucinations had slower responses than the HCs. An early visual N1 contralateral to stimulation side was prominent in all groups of participants but with decreased amplitude in the patients with schizophrenia, especially in the AVH group over the right hemisphere. The amplitude of P3b, a cognitive evaluation component, was also decreased in schizophrenia. Compared to AVH and HC groups, the patients in the NH group had altered microstate patterns: P3b was replaced by a novelty component, P3a. Although the difference between both patient groups was only based on the presence of AVHs, our findings indicated that patients had specific visuospatial deficits associated with a lifetime history of hallucinations: patients with AVHs showed early visual component alterations in the right hemisphere, and those without AVHs had more prominent visuospatial impairment.

The feeling, embodiment and emotion of hallucinations in first episode psychosis: A prospective phenomenological visual-ecological study using novel multimodal unusual sensory experience (MUSE) maps.

BackgroundResearch and practice typically focus upon unimodal hallucinations, especially auditory verbal hallucinations. Contemporary research has however indicated that voice-hearing may co-occur within a broader milieu of feelings, and multimodal hallucinations may be more common than previously thought.MethodsAn observational design asked participants to prospectively document the feeling and modality of hallucinations for one week prior to an interview. Novel visual diary methods involving drawing, writing and body-mapping generated 42 MUSE maps (multimodal unusual sensory experience), analysed with a participatory qualitative method. Twelve people took part: all experiencing hallucinations daily, accessing early intervention in psychosis services, given psychotic-spectrum diagnoses, and living in the community. The study took place during a seven-month period in 2018 at Leicestershire and Rutland's Psychosis Intervention and Early Recovery service (UK).FindingsAll documented hallucinations co-occurred with bodily feelings. Feelings were localised to specific body areas, generalised across the body and extended beyond the body into peripersonal space. Co-occurring emotional feelings most commonly related to confusion, fear and frustration.InterpretationHallucinations were characterised by numerous feelings arising at once, often including multimodal, emotional, and embodied features. Within this study, the immediate feeling of hallucination experiences were readily communicated through prospective, visual, and ecological information gathering methods and particularly those which offer multiple modes of communication (e.g. body-map, visual, written, oral). Uptake of visual, ecological and prospective methods may enhance understandings of lived experiences of hallucinations.Funding: University of Leicester.

EEG Spatiotemporal Patterns Underlying Self-other Voice Discrimination.

There is growing evidence showing that the representation of the human “self” recruits special systems across different functions and modalities. Compared to self-face and self-body representations, few studies have investigated neural underpinnings specific to self-voice. Moreover, self-voice stimuli in those studies were consistently presented through air and lacking bone conduction, rendering the sound of self-voice stimuli different to the self-voice heard during natural speech. Here, we combined psychophysics, voice-morphing technology, and high-density EEG in order to identify the spatiotemporal patterns underlying self-other voice discrimination (SOVD) in a population of 26 healthy participants, both with air- and bone-conducted stimuli. We identified a self-voice-specific EEG topographic map occurring around 345 ms post-stimulus and activating a network involving insula, cingulate cortex, and medial temporal lobe structures. Occurrence of this map was modulated both with SOVD task performance and bone conduction. Specifically, the better participants performed at SOVD task, the less frequently they activated this network. In addition, the same network was recruited less frequently with bone conduction, which, accordingly, increased the SOVD task performance. This work could have an important clinical impact. Indeed, it reveals neural correlates of SOVD impairments, believed to account for auditory-verbal hallucinations, a common and highly distressing psychiatric symptom.

Monitoring Processes and Their Neuronal Correlates as the Basis of Auditory Verbal Hallucinations in a Non-clinical Sample.

Auditory verbal hallucinations (AVH) are a characteristic symptom of psychosis. An influential cognitive model accounting for the mechanisms in the generation of AVHs describes a defective monitoring of inner speech, leading to the misidentification of internally generated thoughts as externally generated events. In this study, we utilized an inner speech paradigm during a simultaneous measurement with functional near-infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI), in order to replicate the findings of neural correlates of inner speech and auditory verbal imagery (AVI) in healthy subjects, reported in earlier studies, and to provide the first validation of the paradigm for fNIRS measurements. To this end, 20 healthy subjects were required to generate and silently recite first and second person sentences in their own voice (inner speech) and imagine the same sentences in a different, alien voice (AVI). Furthermore, questionnaires were deployed to assess the predisposition to acoustic hallucinations and schizotypal traits to investigate their connection to activation patterns associated with inner speech and monitoring processes. The results showed that both methods, fNIRS and fMRI, exhibited congruent activations in key brain areas, claimed to be associated with monitoring processes, indicating that the paradigm seems to be applicable using fNIRS alone. Furthermore, the results showed similar brain areas activated during inner speech and monitoring processes to those from earlier studies. However, our results indicate that the activations were dependent more on the sentence form and less on the imaging condition, showing more active brain areas associated with second person sentences. Integration of the sentence construction into the model of inner speech and deficient monitoring processes as the basis for the formation of AVHs should be considered in further studies. Furthermore, negative correlations between questionnaires' scores and activations in precentral gyrus and premotor cortex indicate a relationship of schizotypal characteristics and a deficient activation pattern.

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.