Combining input from vision and hearing greatly enhances perception when information from one of these senses is degraded or incomplete, such as when tracking objects in foggy, dark or noisy places. This enhancement is of considerable importance because degraded input is the daily situation faced by many people with hearing or vision impairment. We will study the neural processes underlying our ability to combine vision and hearing to create a more reliable and accurate perception of the world.
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
An Integrated Psychoacoustic And High-field FMRI Study Of Auditory Temporal Processsing Dysfunction In Schiophrenia.
Funder
National Health and Medical Research Council
Funding Amount
$306,000.00
Summary
This research seeks to improve our understanding of the causes of brain dysfunction in schizophrenia. This chronic and debilitating psychiatric disorder is usually accompanied by dramatic symptoms such as hallucinations, delusions, paranoia and disordered patterns of thinking. Based on our interpretation of evidence from a number of fields of schizophrenia research we suspect that the brain dysfunction in schizophrenia may not in the brain areas responsible for those dramatic symptoms but occurs ....This research seeks to improve our understanding of the causes of brain dysfunction in schizophrenia. This chronic and debilitating psychiatric disorder is usually accompanied by dramatic symptoms such as hallucinations, delusions, paranoia and disordered patterns of thinking. Based on our interpretation of evidence from a number of fields of schizophrenia research we suspect that the brain dysfunction in schizophrenia may not in the brain areas responsible for those dramatic symptoms but occurs initially in the very basic sensory regions of the brain. These regions can be thought of as providing the building blocks of our perceptions, that ultimately allow us to see, hear, smell and feel. Our previous research shows that people with schizophrenia have a very specific problem in the way that they perceive sounds. Using measures of brain activity, people with schizophrenia show consistent evidence that their brains do not process some of the timing information contained in sound. This is not the same as saying that people with schizophrenia are deaf, the deficits we see are much more subtle. It's a bit like the chaos theory analogy of a butterfly fluttering in Brazil and causing a typhoon in China. We think that very small alterations in brain activity in the initial stages of sensory processing can cascade through successively more complex stages of the brain, eventually creating the psychotic storm that becomes evident as the primary symptoms of schizophrenia. The brain regions we are interested in are located down at the base of the brain, in the brainstem, and it is only recently that the technology and methods of analysis we need to look at this activity have been developed. In this research we will be using functional magnetic resonance imaging and sophisticated hearing tests to examine whether these brain regions show the alterations we expect. If so, this will mean that the brain dysfunction in schizophrenia is quite different to what is currently believed.Read moreRead less
A decade ago the adult brain was thought of as a structurally-fixed organ. Against this are well-documented cases of slow recovery after massive injuries or stroke. Simple models of brain injury using the tactile, visual and auditory systems of animals as models have now revealed multiple stages of recovery (plasticity). Some of these are inbuilt into the wiring of the neural systems such that functional plasticity can result without the need for any structural or cellular changes. A second grou ....A decade ago the adult brain was thought of as a structurally-fixed organ. Against this are well-documented cases of slow recovery after massive injuries or stroke. Simple models of brain injury using the tactile, visual and auditory systems of animals as models have now revealed multiple stages of recovery (plasticity). Some of these are inbuilt into the wiring of the neural systems such that functional plasticity can result without the need for any structural or cellular changes. A second group of plastic phenomena depend upon minute changes in the connections between neurons and these are invoked in the first few days following an injury (synaptic plasticity; changes in the pattern and strength of the connections between neurons). Aside from being model systems, there are also parallels of this plasticity with clinical situations such as losses in hearing and sight, and of the adaptations made by the brain in response to prosthetics (e.g. bionic ear) and resorative surgery but the degree of relevance for these situations is unclear. An intriguing aspect of the experiments on auditory and visual systems is that neurons with inputs from both ears, or both eyes, undergo the plastic changes when the relevant sense organ on only one side is damaged but the other is intact. In fact, on the basis of the limited available evidence, it appears that the changes are independent of there being a normal input from the other side. This is difficult to explain in terms of the modern understanding neuronal plasticity at a cellular level. It is thus proposed to study both auditory and visual models of this brain plasticity with stimuli which are systematically varied to extract the extent of bilateral interaction in the induced plasticity. This will enable prediction of how these plasticity mechanisms will be involved in adaptations made to prosthetics and surgical corrections.Read moreRead less
Abnormal Auditory System Function In Schizophrenia: An ERP And MEG Study Of Its Origin, Course And Generality.
Funder
National Health and Medical Research Council
Funding Amount
$250,770.00
Summary
In 1991, an Australian group found that schizophrenia patients have a reduced brain response to deviant sounds in a repeating pattern of identical sounds. Deviant sounds produce a brain electrical response known as mismatch negativity which is generated by the auditory cortex in the brain's temporal lobes and by adjacent areas in the frontal lobes. A smaller mismatch negativity in patients has since been replicated in laboratories in the US, Europe and Australia. The importance of this finding i ....In 1991, an Australian group found that schizophrenia patients have a reduced brain response to deviant sounds in a repeating pattern of identical sounds. Deviant sounds produce a brain electrical response known as mismatch negativity which is generated by the auditory cortex in the brain's temporal lobes and by adjacent areas in the frontal lobes. A smaller mismatch negativity in patients has since been replicated in laboratories in the US, Europe and Australia. The importance of this finding is that it had not been previously recognised that patients have low level auditory problems that could potentially have a profound impact on higher level functions. Finnish researchers have gone on to show in healthy individuals that mismatch negativity can reveal important features about how well the auditory system works, e.g., for the brain to respond to a deviant sound, it must have a memory of what happened in the past. Mismatch negativity provides a measure of the integrity of these memory functions. But it also provides an index of how well the auditory system discriminates different aspects of sound, pitch, loudness, and temporal features, such as duration. There are hints in our data and from US researchers that processing of the temporal features of sounds is particularly impaired in schizophrenia. We have also recently discovered that first-degree relatives of patients may have a similar deficit. The aim of this project is to use mismatch negativity to probe what is wrong with the auditory system in schizophrenia and those at risk (first degree relatives). Is it the areas of the brain primarily involved in sound perception (the temporal lobes) that are faulty or is the problem in the frontal lobes? Is it the case that processing of temporal features are particularly compromised and if so, is this a biological marker for schizophrenia. Answers to these questions will greatly enhance our understanding of the nature of the brain dysfunction in schizophrenia.Read moreRead less
In the normal process of hearing, the brain actively selects sounds of interest from competing background sounds. This normal auditory function is indispensible for children and adults to cope in non-optimal listening environments, however the mechanisms by which such performance is achieved are poorly understood. This project will investigate the nerve circuits that enable this to occur and will also investigate how these circuits malfunction in various types of partial deafness. The results wi ....In the normal process of hearing, the brain actively selects sounds of interest from competing background sounds. This normal auditory function is indispensible for children and adults to cope in non-optimal listening environments, however the mechanisms by which such performance is achieved are poorly understood. This project will investigate the nerve circuits that enable this to occur and will also investigate how these circuits malfunction in various types of partial deafness. The results will improve our understanding of how we detect sounds and the impact of hearing pathologies on this process.Read moreRead less