Auditory hallucinations in adults with hearing impairment: a large prevalence study

Musical hallucination or musical obsession? A differential diagnosis between two cases

Musical hallucinations and musical obsessions are distinct phenomena. The first can be understood as a manifestation of the musical ear syndrome, which produces deafferentation auditory hallucinations, while the latter is an obsessive symptom of obsessive-compulsive disorders. Both symptoms are often poorly understood and mistaken for one another or for signs of psychotic disorders. We report two cases, one characterized by musical hallucinations and the other by musical obsessions, both with comorbid hearing impairment, which is the main confounding factor in their differential diagnosis. We critically compare the two cases and their key features, allowing diagnostic differentiation and a targeted therapeutic approach.

Musical hallucinations, secondary delusions, and lack of insight: results from a cohort study

Introduction

Although musical hallucinations do not tend to be accompanied by delusions, occasionally patients persistently accuse others of being responsible for causing the music they perceive, sometimes with severe social consequences such as frequently calling the police or moving house. In this study we seek to broaden our understanding of this rare type of musical hallucination that comes with secondary delusions and lack of insight, and to explore associations, underlying mechanisms, and treatment possibilities.

Methods

The present study is part of a cohort study on musical hallucinations carried out in the Netherlands from 2010 through 2023. Participants underwent testing with the aid of the MuHa Questionnaire, Launay-Slade Hallucinations Scale (LSHS), Schizotypal Personality Questionnaire (SPQ), Hamilton Depression Rating Scale (HDRS), and Mini Mental State Examination (MMSE). Additionally, they underwent a brain MRI, electroencephalogram, and audiological testing.

Results

Five patients out of a group of N = 81 (6%) lacked insight and presented with secondary delusions regarding the perceived music. They were all female, of advanced age, and hearing-impaired, and were diagnosed with cognitive impairment. In three patients (60%), risperidone was started. This had a positive effect on the hallucinations and secondary delusions.

Conclusion

The pathophysiological process underlying musical hallucinations is multifactorial in nature. We consider cognitive impairment the most likely contributing factor of the secondary delusions and lack of insight encountered in our patients, and antipsychotics the most beneficial treatment. On the basis of these small numbers, no definite conclusions can be drawn, so further research is needed to elucidate the underlying mechanisms and to develop evidence-based treatment methods for people experiencing this rare and debilitating combination of symptoms. Since the black box warning of risperidone cautions against the use of this drug in elderly persons with dementia, a proper comparison with the efficacy and safety of other antipsychotics for this group is paramount.

Conversations about mental illness and health in adult audiological rehabilitation

OBJECTIVE

To understand the nature of mental health discussions in audiological rehabilitation, specifically, the types of conversations, when and how they are initiated, and the participant factors associated with discussing mental health.

DESIGN

A cross-sectional descriptive survey including quantitative (multiple choice) and qualitative (free-text) questions regarding mental health discussions between audiologists and clients.

STUDY SAMPLE

A convenience sample of 118 Australian audiologists working in adult audiological rehabilitation.

RESULTS

The majority of participants (95.8%) reported having engaged in discussions with clients about mental illness and health at some point throughout their career. The frequency of these discussions varied across participants: 7% rarely discuss, 50% discuss occasionally, 30% discuss with about half their clients and 13% have discussions with most clients. Many participants (85.6%) reported that clients would initiate these conversations, most often via disclosing the impacts of hearing loss on clients' lives.

CONCLUSIONS

Most audiologists will encounter clients with mental health concerns, and many will engage in conversations about psychological symptoms, therefore, training audiologists to recognise and address verbal and non-verbal cues regarding mental health may help to promote person-centred care and potentially improve outcomes.

Third-generation genome sequencing implicates medium-sized structural variants in chronic schizophrenia

Background

Schizophrenia (SCZ) is a heterogeneous psychiatric disorder, with significant contribution from genetic factors particularly for chronic cases with negative symptoms and cognitive deficits. To date, Genome Wide Association Studies (GWAS) and exome sequencing have associated SCZ with a number of single nucleotide polymorphisms (SNPs) and copy number variants (CNVs), but there is still missing heritability. Medium-sized structural variants (SVs) are difficult to detect using SNP arrays or second generation sequencing, and may account for part of the missing heritability of SCZ.

Aims and objectives

To identify SVs associated with severe chronic SCZ across the whole genome.

Study design

10 multiplex families with probands suffering from chronic SCZ with negative symptoms and cognitive deficits were recruited, with all their affected members demonstrating uni-lineal inheritance. Control subjects comprised one affected member from the affected lineage, and unaffected members from each paternal and maternal lineage.

Methods

Third generation sequencing was applied to peripheral blood samples from 10 probands and 5 unaffected controls. Bioinformatic tools were used to identify SVs from the long sequencing reads, with confirmation of findings in probands by short-read Illumina sequencing, Sanger sequencing and visual manual validation with Integrated Genome Browser.

Results

In the 10 probands, we identified and validated 88 SVs (mostly in introns and medium-sized), within 79 genes, which were absent in the 5 unaffected control subjects. These 79 genes were enriched in 20 biological pathways which were related to brain development, neuronal migration, neurogenesis, neuronal/synaptic function, learning/memory, and hearing. These identified SVs also showed evidence for enrichment of genes that are highly expressed in the adolescent striatum.

Conclusion

A substantial part of the missing heritability in SCZ may be explained by medium-sized SVs detectable only by third generation sequencing. We have identified a number of such SVs potentially conferring risk for SCZ, which implicate multiple brain-related genes and pathways. In addition to previously-identified pathways involved in SCZ such as neurodevelopment and neuronal/synaptic functioning, we also found novel evidence for enrichment in hearing-related pathways and genes expressed in the adolescent striatum.

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.

Predictive waves in the autism-schizophrenia continuum: A novel biobehavioral model

The brain is a predictive machine. Converging data suggests a diametric predictive strategy from autism spectrum disorders (ASD) to schizophrenic spectrum disorders (SSD). Whereas perceptual inference in ASD is rigidly shaped by incoming sensory information, the SSD population is prone to overestimate the precision of their priors' models. Growing evidence considers brain oscillations pivotal biomarkers to understand how top-down predictions integrate bottom-up input. Starting from the conceptualization of ASD and SSD as oscillopathies, we introduce an integrated perspective that ascribes the maladjustments of the predictive mechanism to dysregulation of neural synchronization. According to this proposal, disturbances in the oscillatory profile do not allow the appropriate trade-off between descending predictive signal, overweighted in SSD, and ascending prediction errors, overweighted in ASD. These opposing imbalances both result in an ill-adapted reaction to external challenges. This approach offers a neuro-computational model capable of linking predictive coding theories with electrophysiological findings, aiming to increase knowledge on the neuronal foundations of the two spectra features and stimulate hypothesis-driven rehabilitation/research perspectives.

Self-isolation, psychotic symptoms and cognitive problems during the COVID-19 worldwide outbreak

The worldwide outbreak of CoronaVirus Disease appeared in 2019 (COVID-19) has forced millions of people into social isolation. Past research has documented negative psychological effects of self-isolation during health crises, in terms of stress, anger or depressive symptoms, but overall ignored psychotic symptoms and cognitive problems. The present study (n = 211) examined the relationship between the conditions of self-isolation - that is, duration, living space, frequency of social interactions - and psychotic symptoms and cognitive problems during the COVID-19 outbreak. The frequency of both psychotic symptoms and cognitive problems was associated with time since last conversation, with time since the person last left home and with smaller living space. Participants who reported an increase of psychotic symptoms and cognitive problems during the period of the pandemic also showed higher levels of symptoms. Although social isolation is an effective method for preventing the COVID-19 from spreading, for some individuals it is associated with an increased risk of developing psychotic symptoms.

Three cases of Charles Bonnet Syndrome in patients with advanced glaucomatous visual field loss but preserved visual acuity

Purpose

To describe three cases of Charles Bonnet syndrome (CBS) in glaucoma patients with preserved visual acuity.

Methods

Three glaucoma patients who had taken part in a recent CBS study were interviewed about their hallucinations. The patients underwent macular optical coherence tomography (OCT) of both eyes. The visual function was evaluated with visual field measurement (Humphrey visual field analyser) and visual acuity testing (Snellen scale).

Results

All three patients had preserved visual acuity (≥0.5 in both eyes) and at least one eye with advanced visual field defect (Mean Deviation worse than −12.00 decibel). They all reported vivid visual hallucinations with insight into the unreal nature of the hallucinations.

Conclusion

Charles Bonnet syndrome can occur in glaucoma despite preserved visual acuity. Awareness of this relation is desirable among clinicians, as it will improve communication with patients.

Auditory Hallucinations: An Audiological Horizon?

BACKGROUND

 Interesting data and theories have emerged regarding auditory hallucinations (AHs) in patients with schizophrenia. The possibility that these patients may have changes in the anatomy of the auditory cortex and/or subcortical structures of the central auditory nervous system and present with deficits on audiological tests is important information to the audiology community. However, it seems clear that, in general, audiologists are not sufficiently aware of these findings.

PURPOSE

 There are two main purposes of this article: (1) to educate audiologists about AHs related to schizophrenia and related issues, and (2) to encourage audiologists and hearing scientists to become involved in the evaluation and research of AHs. This fascinating disorder is one in which audiologists/hearing scientists are well suited to make a significant contribution.

RESEARCH DESIGN

 A review and synthesis of the literature was conducted. Relevant literature was identified through PubMed, Google Scholar, as well as independent book chapters and article searches. Keywords driving the searches were AHs, auditory illusions, verbal and musical hallucinations, schizophrenia, and central auditory disorders. Given the currency of the topic, the information collected was primarily between 1990 and 2020.

STUDY SAMPLE

 The review is organized around categorization, prevalence, models, mechanisms, anatomy, pathophysiology, and audiological correlates related to AHs.

DATA COLLECTION AND ANALYSIS

 Searches were conducted using well-known search engines and manual searches by each author. This information on AHs was then analyzed collectively by the authors for useful background and relevance, as well as important for the field of audiology.

RESULTS

 Several anatomical, physiological, and functional imaging studies have shown compromise of the auditory cortex in those with schizophrenia and AHs. Potentially related to this, are studies that demonstrated sub-par performance on behavioral audiologic measures for this unique clinical population. These findings align well with the kind of hearing disorder for which audiologists are well-trained to make significant contributions.

CONCLUSION

 Neurobiological and audiological evidence is accumulating on patients with schizophrenia and AH potentially rendering it as both an auditory and psychiatric disorder. Audiologists should consider expanding their horizon and playing a role in the clinical investigation of this disorder.

A Systematic Review of the experimental induction of auditory perceptual experiences

BACKGROUND AND OBJECTIVES

Voice-hearing exists on a continuum and research studies have utilised experimental paradigms in an attempt to induce unusual auditory experiences in clinical and non-clinical samples. The aim of the current review was to systematically identify, review and appraise voice-hearing induction paradigms in order to guide researchers.

METHODS

Five databases were searched for studies in which an experimental manipulation was used with the aim of inducing an auditory experience akin to voice-hearing. Papers were assessed for quality and the voice-hearing paradigms critically appraised.

RESULTS

Forty-nine studies, included in 41 papers, were reviewed. Studies were organised into five groups based on the type of voice-hearing paradigm used: sensory deprivation/limitation; hallucination suggestion; combined suggestion and ambiguous stimulus; signal detection and voice detection tasks; and auditory discrimination/transformation. Signal and voice detection tasks were found to be the most robust paradigms. The quality of paradigms was assessed, and their strengths and limitations evaluated, including evidence in relation to their utility, ecological validity and usability.

LIMITATIONS

The current review excluded case studies, grey literature and studies which were not written in the English language, and as such voice-hearing paradigms may have been missed.

CONCLUSIONS

Voice-hearing paradigms vary in their ecological validity and experimental robustness. A challenge for future research is to develop a paradigm in which internally generated material can be attributed externally in a way that more closely represents inner speech and the experience of voice-hearing.

Spontaneous brain activity underlying auditory hallucinations in the hearing-impaired

Auditory hallucinations, the perception of a sound without a corresponding source, are common in people with hearing impairment. Two forms can be distinguished: simple (i.e., tinnitus) and complex hallucinations (speech and music). Little is known about the precise mechanisms underlying these types of hallucinations. Here we tested the assumption that spontaneous activity in the auditory pathways, following deafferentation, underlies these hallucinations and is related to their phenomenology. By extracting (fractional) Amplitude of Low Frequency Fluctuation [(f)ALFF] scores from resting state fMRI of 18 hearing impaired patients with complex hallucinations (voices or music), 18 hearing impaired patients with simple hallucinations (tinnitus or murmuring), and 20 controls with normal hearing, we investigated differences in spontaneous brain activity between these groups. Spontaneous activity in the anterior and posterior cingulate cortex of hearing-impaired groups was significantly higher than in the controls. The group with complex hallucinations showed elevated activity in the bilateral temporal cortex including Wernicke's area, while spontaneous activity of the group with simple hallucinations was mainly located in the cerebellum. These results suggest a decrease in error monitoring in both hearing-impaired groups. Spontaneous activity of language-related areas only in complex hallucinations suggests that the manifestation of the spontaneous activity represents the phenomenology of the hallucination. The link between cerebellar activity and simple hallucinations, such as tinnitus, is new and may have consequences for treatment.

Hallucinations and other psychotic experiences across diagnoses: A comparison of phenomenological features

Although psychotic experiences are prevalent across many psychiatric, neurological, and medical disorders, investigation of these symptoms has largely been restricted to diagnostic categories. This study aims to examine phenomenological similarities and differences across a range of diagnoses. We assessed frequency, severity and phenomenology of psychotic experiences in 350 outpatients including; participants with schizophrenia spectrum disorders, hearing impairment, Parkinson's disease, Lewy Body Dementia, Alzheimer's disease, visual impairment, posttraumatic stress disorder, borderline personality disorder, and participants with recent major surgery. Psychotic phenomena were explored between these groups using the Questionnaire for Psychotic Experiences (QPE). Participants with major psychiatric disorders reported a combination of several psychotic experiences, and more severe experiences compared to all other disorders. Participants with recent major surgery or visual impairment experienced isolated visual hallucinations. Participants with hearing impairment reported isolated auditory hallucinations, whereas the neurodegenerative disorders reported visual hallucinations, occasionally in combination with hallucinations in another modality or delusions. The phenomenology between neurodegenerative disorders, and within major psychiatric disorders showed many similarities. Our findings indicate that the phenomenology of psychotic experiences is not diagnosis specific, but may rather point to the existence of various subtypes across diagnoses. These subtypes could have a different underlying etiology requiring specific treatment.

Musical hallucinations with a right frontotemporal stroke

have been reported in association with psychiatric diseases, brain stem strokes, deafness, degenerative diseases, intoxications, pharmacologic agents, and epilepsy. We present a patient who in the absence of these disorders developed musical hallucinations from an infarction of the right hemisphere that primarily injured his right frontal and anterior temporal lobes. This report discusses some of the possible mechanisms for this patient's presentation. Although the mechanism of his musical hallucinations remains unclear, recognition of this uncommon syndrome is important when structuring rehabilitation and management for patients with stroke who have this disorder.

A Review of Multimodal Hallucinations: Categorization, Assessment, Theoretical Perspectives, and Clinical Recommendations

Hallucinations can occur in different sensory modalities, both simultaneously and serially in time. They have typically been studied in clinical populations as phenomena occurring in a single sensory modality. Hallucinatory experiences occurring in multiple sensory systems-multimodal hallucinations (MMHs)-are more prevalent than previously thought and may have greater adverse impact than unimodal ones, but they remain relatively underresearched. Here, we review and discuss: (1) the definition and categorization of both serial and simultaneous MMHs, (2) available assessment tools and how they can be improved, and (3) the explanatory power that current hallucination theories have for MMHs. Overall, we suggest that current models need to be updated or developed to account for MMHs and to inform research into the underlying processes of such hallucinatory phenomena. We make recommendations for future research and for clinical practice, including the need for service user involvement and for better assessment tools that can reliably measure MMHs and distinguish them from other related phenomena.

Hallucinations in Older Adults: A Practical Review

Older adults experience hallucinations in a variety of social, physical, and mental health contexts. Not everyone is open about these experiences, as hallucinations are surrounded with stigma. Hence, hallucinatory experiences in older individuals are often under-recognized. They are also commonly misunderstood by service providers, suggesting that there is significant scope for improvement in the training and practice of professionals working with this age group. The aim of the present article is to increase knowledge about hallucinations in older adults and provide a practical resource for the health and aged-care workforce. Specifically, we provide a concise narrative review and critique of (1) workforce competency and training issues, (2) assessment tools, and (3) current treatments and management guidelines. We conclude with a brief summary including suggestions for service and training providers and future research.

[Psychopathological consequences of confinement]

The psychological effects of isolation have already been described in the literature (polar expeditions, submarines, prison). Nevertheless, the scale of confinement implemented during the COVID-19 pandemic is unprecedented. In addition to reviewing the published studies, we need to anticipate the psychological problems that could arise during or at a distance from confinement. We have gone beyond the COVID-19 literature in order to examine the implications of the known consequences of confinement, like boredom, social isolation, stress, or sleep deprivation. Anxiety, post-traumatic stress disorder, depression, suicidal or addictive behaviours, domestic violence are described effects of confinement, but the mechanisms of emergence of these disorders and their interrelationships remain to be studied. For example, what are the mechanisms of emergence of post-traumatic stress disorders in the context of confinement? We also remind the reader of points of vigilance to be kept in mind with regard to eating disorders and hallucinations. Hallucinations are curiously ignored in the literature on confinement, whereas a vast literature links social isolation and hallucinations. Due to the broad psychopathological consequences, we have to look for these various symptoms to manage them. We quickly summarize the diagnostic and therapeutic approaches already in place, such as telemedicine, which is undergoing rapid development during the COVID-19 crisis.

Deafferentation as a cause of hallucinations

PURPOSE OF REVIEW

The association between hallucinations and sensory loss, especially vision- and hearing-impairment, has been firmly established over the past years. The deafferentation theory, a decrease of the threshold for activation in the brain and the consequential imbalance between excitatory and inhibitory brain networks, is hypothesized to underly this relationship. Here we review the studies investigating this theory with a focus on the most recent literature to better understand the contribution of sensory loss to hallucinations.

RECENT FINDINGS

A large cross-sectional study has recently confirmed the relationship between auditory impairment and deafferentation. However, the underlying mechanisms of deafferentation are still under debate, with hyperexcitability and deviations in bottom-up and top-down processes being the most likely explanations. Social isolation following sensory impairment increases the risk for hallucinations. Better knowledge and awareness about the contribution of deafferentation and loneliness would benefit diagnosis and treatment of hallucinations.

SUMMARY

Studies imply activity in higher order areas, corresponding to the functional mapping of sensory system, and a general state of higher excitability as neurobiological explanation. Auditory deafferentation, tinnitus and other auditory hallucinations, likely lie on a continuum. Social isolation mediates psychotic symptoms in sensory-impaired individuals. Currently, there is no standard treatment for deafferentation hallucinations.

Modality-general and modality-specific processes in hallucinations

There is a growing recognition in psychosis research of the importance of hallucinations in modalities other than the auditory. This has focused attention on cognitive and neural processes that might be shared by, and which might contribute distinctly to, hallucinations in different modalities. In this article, I address some issues around the modality-generality of cognitive and neural processes in hallucinations, including the role of perceptual and reality-monitoring systems, top-down and bottom-up processes in relation to the psychological and neural substrates of hallucinations, and the phenomenon of simultaneous multimodal hallucinations of the same entity. I suggest that a functional systems approach, inspired by some neglected aspects of the writings of A. R. Luria, can help us to understand patterns of hallucinatory experience across modalities and across clinical and non-clinical groups. Understanding the interplay between modality-general and modality-specific processes may bear fruit for improved diagnosis and therapeutic approaches to dealing with distressing hallucinations.

Musical hallucinations and their relation with epilepsy

Musical hallucinations are poorly understood phenomena. Their relation with epilepsy was first described over a century ago, but never systematically explored. We, therefore, reviewed the literature, and assessed all descriptions of musical hallucinations attributed to epileptic activity. Our search yielded 191 articles, which together describe 983 unique patients, with 24 detailed descriptions of musical hallucinations related to epilepsy. We also describe six of our own patients. Based on the phenomenological descriptions and neurophysiological data, we distinguish four subgroups of epilepsy-related musical hallucination, comprising auras/ictal, inter-ictal and post-ictal phenomena, and phenomena related to brain stimulation. The case descriptions suggest that musical hallucinations in epilepsy can be conceptualised as lying on a continuum with other auditory hallucinations, including verbal auditory hallucinations, and—notably—tinnitus. To account for the underlying mechanism we propose a Bayesian model involving top-down and bottom-up prediction errors within the auditory network that incorporates findings from EEG and MEG studies. An analysis of phenomenological characteristics, pharmacological triggers, and treatment effects suggests wider ramifications for understanding musical hallucinations. We, therefore, conclude that musical hallucinations in epilepsy open a window to understanding these phenomena in a variety of conditions.

Musical hallucinations, musical imagery, and earworms: A new phenomenological survey

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We conducted a phenomenological survey comparing musical hallucinations to other inner music.

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MH were more likely to be reported as externally located than other experiences.

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MH were less controllable and less familiar than imagery or earworms.

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MH were less likely to include lyrical content than other forms of inner music.

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Individuals with higher levels of musical expertise were less likely to report MH.

Musical hallucinations (MH) account for a significant proportion of auditory hallucinations, but there is a relative lack of research into their phenomenology. In contrast, much research has focused on other forms of internally generated musical experience, such as earworms (involuntary and repetitive inner music), showing that they can vary in perceived control, repetitiveness, and in their effect on mood. We conducted a large online survey (N = 270), including 44 participants with MH, asking participants to rate imagery, earworms, or MH on several variables. MH were reported as occurring less frequently, with less controllability, less lyrical content, and lower familiarity, than other forms of inner music. MH were also less likely to be reported by participants with higher levels of musical expertise. The findings are outlined in relation to other forms of hallucinatory experience and inner music, and their implications for psychological models of hallucinations discussed.