The Neurobiology Of Auditory Hallucinations: Characterisation Of Dysfunction Within A Neural Circuitry Model.
Funder
National Health and Medical Research Council
Funding Amount
$299,625.00
Summary
This is a highly innovative research proposal which is based on years of extensive research by our group. Auditory hallucinations are a prominent and potentially disabling symptom of psychosis, however it is extremely difficult to study them scientifically. Past research by our group (and other groups internationally) has indicated that an extensive network in the brain is activated whenever auditory hallucinations occur, but the source of this brain activity is unclear. It was thought that the ....This is a highly innovative research proposal which is based on years of extensive research by our group. Auditory hallucinations are a prominent and potentially disabling symptom of psychosis, however it is extremely difficult to study them scientifically. Past research by our group (and other groups internationally) has indicated that an extensive network in the brain is activated whenever auditory hallucinations occur, but the source of this brain activity is unclear. It was thought that the source may be the same brain circuits that are involved in generating inner speech or monitoring it, but our past research has ruled out these possibilities. Instead, our recent work suggests that auditory hallucinations may be associated with poorly functioning connections within central auditory processing circuits, specifically between left and right auditory association cortical regions. We conceptualise hallucinations as an abnormal and involuntary form of memory retrieval consequent to this dysfunction. Our study will pioneer methods of measuring connectivity in the brain circuits identified in our model, using a combination of functional magnetic resonance imaging (fMRI) and electroencephalographic (EEG) techniques in tandem with tests of central auditory processing. We believe that sufferers may benefit from understanding the physical processes which cause hallucinations. We also believe that a better understanding of hallucinations may lead to a better understanding of schizophrenia and the psychoses, which may in turn help in the development of better ways of treating these illnesses.Read moreRead less
Episodic Memory Dysfunction As A Basis For Auditory Hallucinations In Schizophrenia
Funder
National Health and Medical Research Council
Funding Amount
$278,517.00
Summary
Auditory hallucinations (AHs) occur frequently in people who suffer from schizophrenia. This symptom usually involves hearing voices that the hallucinator firmly believes originate from other people. The voices are often intrusive, abusive and persecutory. They are a source of significant stress and may result in self harm or harm to others. Our investigations will attempt to provide experimental support for the theory that AHs represent a misremembering of voices which were heard in the past. W ....Auditory hallucinations (AHs) occur frequently in people who suffer from schizophrenia. This symptom usually involves hearing voices that the hallucinator firmly believes originate from other people. The voices are often intrusive, abusive and persecutory. They are a source of significant stress and may result in self harm or harm to others. Our investigations will attempt to provide experimental support for the theory that AHs represent a misremembering of voices which were heard in the past. We will do this by attempting to characterise specific problems that hallucinators have in identifying when they heard verbal fragments and who said them. We plan to conduct our investigations at five levels. First, we will determine how accurate hallucinators' memories are for context by the use of special neuropsychological tests. Second, we will find out if hallucinators form more false memories than comparison subjects using a test in which such incorrect recollections occur commonly. Third, we will determine if hallucinators have a tendency to reconstruct the characteristics of false verbal memories in the same way that they reconstruct the characteristics of their hallucinations. Fourth, we will attempt to suppress these false verbal memories and finally, we will characterise those brain regions which are activated during true and false memory formation by using blood flow analysis technology in order to identify networks of brain activity which preferentially malfunction in hallucinating patients. This study provides the prospect of adding substantially to our understanding of the mechanisms underlying auditory hallucinations and to lead to the development of new cognitively-based treatments for the symptom.Read moreRead less
Efficacy Of Treatment For Resistant Command Hallucinations.
Funder
National Health and Medical Research Council
Funding Amount
$343,875.00
Summary
Auditory hallucinations (AHs), often described as voices, are a common symptom of schizophrenia and psychoses. Command hallucinations (CHs) are a type of AH in which the voice heard by the patient commands him or her to perform a particular action. The nature of the directive may vary from inconsequential actions to commands to harm the patient or others. There is widespread public concern about the danger individuals with schizophrenia or related disorders pose to themselves and to the communit ....Auditory hallucinations (AHs), often described as voices, are a common symptom of schizophrenia and psychoses. Command hallucinations (CHs) are a type of AH in which the voice heard by the patient commands him or her to perform a particular action. The nature of the directive may vary from inconsequential actions to commands to harm the patient or others. There is widespread public concern about the danger individuals with schizophrenia or related disorders pose to themselves and to the community. There is firm evidence pointing to the important role that CHs play in propelling psychotic individuals into serious and damaging actions. We have found, however, that most individuals who comply with dangerous CHs do so, not because they are angry, violent, antisocial or wish to cause harm, but because they feel powerless to resist. Though CHs are one of the most disturbing symptoms of psychosis, standard treatment has proved to be of limited benefit. This study will evaluate the effectiveness of Treatment of Resistant Command Hallucinations (TORCH), an innovative treatment for CHs. TORCH is an extension of an existing treatment for psychosis that we previously developed. TORCH aims to reduce the distress, worry and harmful or self-defeating behaviour associated with CHs by arming the patient with effective strategies that will enhance resistance and reduce compliance. The project has clear implications for improved clinical and therapeutic management of CHs with major public health, clinical and forensic repercussions. The consequences of being formally assessed as being at risk of acting violently result in the potential for substantial restrictions on the freedom of the individual. The availability of TORCH may prompt a less restrictive management of individuals at risk of dangerous behaviour and promote a more optimistic attitude amongst clinicians. Relatives and carers also stand to benefit through reduction in perplexing and fear-inducing behaviours.Read moreRead less
Early Indicators Of Noise Injury: Are Decreased Auditory Processing Skills Evident In Noise-exposed Adults Prior To Diagnosis Of Hearing Loss?
Funder
National Health and Medical Research Council
Funding Amount
$367,605.00
Summary
Recent research indicates that noise-exposed individuals with similar hearing thresholds to non-noise exposed counterparts are more likely to have diminished temporal and spectral auditory processing abilities. This research aims to determine the relationship between noise exposure levels and auditory processing difficulties; the influence of musical training in ameliorating these difficulties; and a neurological model of causation, operation and possible remediation of these difficulties.
Intrinsic Hearing Protection Mechanisms: A Pathway To Prevention Of Noise-induced Hearing Loss
Funder
National Health and Medical Research Council
Funding Amount
$625,900.00
Summary
Noise-induced hearing loss (NIHL) is a significant contributor to the total burden of disease. We recently determined that when the ear is exposed to sustained noise, the cochlea is protected from damage by activation of a specific (P2X2) receptor, evident as reversible hearing adaptation. This study will determine the downstream signalling from this receptor. This will support assessment of vulnerability to NIHL and contribute to development of hearing therapeutics.
Cochlear Type II Neurons In Contralateral Suppression
Funder
National Health and Medical Research Council
Funding Amount
$459,434.00
Summary
Sound in one ear affects hearing in the other ear. This contralateral suppression is important for hearing attention and protection from noise damage. We will test the hypothesis that cochlear type II sensory neurons provide the sensory input for this process using models where neuronal development is altered, or the neurons are removed. The study addresses hearing disability in society, facilitating cochlear prosthesis development and the understanding of hearing loss.
Auditory Processing Deficits In Specific Language Impairment And Specific Reading Disability:Their Effects And Treatment
Funder
National Health and Medical Research Council
Funding Amount
$314,250.00
Summary
One possible cause of specific language impairment (SLI) and specific reading disability (SRD; commonly known as dyslexia) is an inability to discriminate between sounds. Such an impairment could affect the ability to discriminate between simple speech sounds (phonemes) which are the basic building blocks for developing spoken language and reading skills. How many children with SLI or SRD have poor sound discrimination? What pattern of spoken language and reading impairments do these children ha ....One possible cause of specific language impairment (SLI) and specific reading disability (SRD; commonly known as dyslexia) is an inability to discriminate between sounds. Such an impairment could affect the ability to discriminate between simple speech sounds (phonemes) which are the basic building blocks for developing spoken language and reading skills. How many children with SLI or SRD have poor sound discrimination? What pattern of spoken language and reading impairments do these children have as a result of this impairment? Can poor sound discrimination be fixed? If it can, does it improve spoken language and reading impairments? And if it does, does it have an immediate effect or does it take some time to make a difference? These are some of the questions that will be addressed by this research. The answers will help us develop a training program that focuses specifically on improving the sound discrimination abilities of children who really need it. This will be a more efficient and inexpensive (if not free) than the Fast ForWord program that trains multiple non-verbal and verbal processing abilities regardless of whether a child has an impairment in all (or any) of these abilities and is therefore time consuming (approximately 80 hours) and expensive (approximately $AUD2000). The data will also help up better identify the spoken and written language profiles that characterise children who have sound discrimination deficits so we can better predict whether they would benefit from training programs such as Fast ForWord. And the data will tell use whether impaired sound discrimination can be used to predict whether infants might be at risk for later spoken language and reading problems.Read moreRead less
Organization And Function Of Primate Auditory Cortex
Funder
National Health and Medical Research Council
Funding Amount
$271,671.00
Summary
The conscious perception of speech and other sounds depends on processing within a brain region known as the auditory cortex. Compared to other brain areas, relatively little is known about the organization and function of this structure. Recent studies have proposed that the auditory cortex may be anatomically subdivided into functional modules, each of which is specialized for processing different types of information. However, the evidence for multiple processing streams is fragmentary, and n ....The conscious perception of speech and other sounds depends on processing within a brain region known as the auditory cortex. Compared to other brain areas, relatively little is known about the organization and function of this structure. Recent studies have proposed that the auditory cortex may be anatomically subdivided into functional modules, each of which is specialized for processing different types of information. However, the evidence for multiple processing streams is fragmentary, and not entirely consistent. The proposed experiments will combine anatomical and physiological approaches to evaluate the functional organization of auditory cortex in the primate brain. We will map the electrical responses of single brain cells to various complex sounds across the brain surface, and inject dyes to label pathways linking brain areas to one another. The data will allow us to determine whether specific subdivisions of the auditory cortex are specialized for processing different types of infomation, and whether specific subdivisions are linked together to form processing streams specialized for sound recognition and space perception. The results will advance our understanding of the neuronal processing involved in the perception of sound, with possible implications for speech perception. This will help to understand the consequences of brain damage, and may inform the development of hearing aids and artificial voice recognition systems. In addition, this study will help to develop a primate model for studying brain mechanisms of sound recognition that should be useful in research on cochlear implants.Read moreRead less
Organization Of Descending Auditory Projections From Inferior Colliculus To Cochlear Nucleus
Funder
National Health and Medical Research Council
Funding Amount
$473,121.00
Summary
Sensory information gains awareness by ascending brain pathways to reach consciousness. Descending projections, however, have grown in importance because of implications for feedback management of ascending signals. Studies of these pathways will provide insight into auditory processing with respect to selective volume control, calibration adjustments between the two ears, and the extraction of signals from background noise. The data could lead to new strategies for treating hearing disorders.
Risk Factors For Compliance With Command Hallucinations In Psychotic Disorders
Funder
National Health and Medical Research Council
Funding Amount
$180,290.00
Summary
There is widespread public concern about the danger individuals with schizophrenia or related disorders pose to themselves and to the community. Whilst a number of violence risk factors such as being male, exhibiting hostility, and having a prior history of violence are well established, they are of limited use to clinicians in making management decisions. Our study will investigate a different approach to identify individuals and occasions when a sufferer might require more intensive care or ob ....There is widespread public concern about the danger individuals with schizophrenia or related disorders pose to themselves and to the community. Whilst a number of violence risk factors such as being male, exhibiting hostility, and having a prior history of violence are well established, they are of limited use to clinicians in making management decisions. Our study will investigate a different approach to identify individuals and occasions when a sufferer might require more intensive care or observation. Most individuals with schizophrenia experience auditory hallucinations. Amongst these hallucinations, voices that command the individual to undertake a particular action are common; many of these involve significant potential harm to the hallucinator or to other persons. We will attempt to identify those factors that are associated with an individual obeying command hallucinations. Variables to be examined include the characteristics of the hallucinated voices, and the beliefs of the subject about the power of the voices. Subjects will be interviewed to find out whether they have delusions that are consistent with their hallucinations, whether they suffer from Antisocial Personality Disorder, or are dependent on alcohol or drugs. We will also determine whether subjects who report being raised by authoritarian parents, who are dependent on the approval of others, or who see external factors as determining the occurrence of major events in their lives, are more likely to act on their hallucinations. Two groups of 100 patients will be studied. One group will be representative of people living in the community with schizophrenia. The other group will be people with schizophrenia who have been treated by the State Forensic Psychiatric Services. Statistical models will be developed in order to determine the accuracy with which compliance with command hallucinations can be predicted. These models with also reveal which risk factors are the most important.Read moreRead less