Development Of A Diagnostic Test For Bipolar Disorder (BD)
Funder
National Health and Medical Research Council
Funding Amount
$140,330.00
Summary
A unique test that monitors the rate of switching between the hemispheres of the brain in response to visual stimuli has been devised. A patent application covers an apparatus and test to measure the switching rate between the hemispheres and the way in which such measurements can be used as a means to diagnose bipolar disorder (BD). BD, also called manic depression, is a form of depression that currently affects over six million people worldwide with about three million in the USA alone. The co ....A unique test that monitors the rate of switching between the hemispheres of the brain in response to visual stimuli has been devised. A patent application covers an apparatus and test to measure the switching rate between the hemispheres and the way in which such measurements can be used as a means to diagnose bipolar disorder (BD). BD, also called manic depression, is a form of depression that currently affects over six million people worldwide with about three million in the USA alone. The condition has phases of mania and depression and periods of remittance. Full cycles of BD can occur as many as three times a year and for many patients, this is a lifelong condition. BD is effectively treated, once it is diagnosed. It is estimated that 20% of sufferers go undiagnosed and many more are misdiagnosed. The cost of mis- or non-diagnosis is measured by suicides, the financial burden on society with health care, loss of productivity etc, effects on family and associates, crime, etc. Diagnosis to date is achieved mainly by subjective means such as questionnaires. These instruments do not conclusively separate BD from other forms of depression and schizophrenia, for which treatment is quite different. Nor do they allow for factors such as substance abuse and other medical conditions that the patient may be suffering. BD is hereditary with the slow hemispheric switch rate being an indicator of the genetic trait. This phenomenon allows for an objective test for BD, even if an individual has not had an episode of BD. The slow switch allows relatively easy separation of a BD patient from those exhibiting symptoms that may have other causes.Read moreRead less
New research with scanning techniques has confirmed older ideas about the complementary functions of the two hemispheres of the human brain. One major contrast between the two hemispheres concerns their cognitive and emotional styles. The left hemisphere plans and confidently smooths over discrepancies that do not fit the plan while the right hemisphere looks at all possibilities and cautiously highlights the discrepancies. This research project studies the switch between the two hemispheres tha ....New research with scanning techniques has confirmed older ideas about the complementary functions of the two hemispheres of the human brain. One major contrast between the two hemispheres concerns their cognitive and emotional styles. The left hemisphere plans and confidently smooths over discrepancies that do not fit the plan while the right hemisphere looks at all possibilities and cautiously highlights the discrepancies. This research project studies the switch between the two hemispheres that alternately activates these contrasting, but equally valid, viewpoints. The switch is studied directly by optical recording from animal brains. The switch can also be studied in humans using a recent discovery from our laboratory:- that the perceptual rivalries are mediated by a hemispheric switch mechanism. Perceptual rivalry is a phenomenon where continuous, but ambiguous, stimulation leads to a back-and-forth alternation of complementary percepts, a phenomenon that fascinated Salvador Dali and is featured in many of his paintings. The nature of the perceptual switch during rivalry has been debated for centuries. New experiments link perceptual rivalry to the switch of attention between the hemispheres. Using perceptual rivalry as an indirect way to monitor hemispheric switching in humans, we discovered a remarkable feature. The back-and-forth switching process of perceptual rivalry is significantly slower in subjects with bipolar disorder (manic depression), even when they are between episodes and their mood is normal. The timing of the switching process is very stable in an individual, and appears to be similar in identical twins. The speed of the switch mechanism may therefore be inherited. Altered neural rhythms may underly the predisposition, known to run in familes, from which bipolar disorder can be triggered. The aim of the project is to test these propositions about the basis of this common disorder, affecting 1-2% of the population..Read moreRead less
Investigating Caloric Vestibular Stimulation As A Novel Therapeutic Intervention For Chronic Pain, Mania And Depression.
Funder
National Health and Medical Research Council
Funding Amount
$340,963.00
Summary
Chronic pain, mania and depression are common health problems worldwide and represent an enormous burden of illness. Current treatments may be costly, invasive and have serious side-effects. In the proposed project, demonstration of therapeutic benefit with a novel, simple method of brain stimulation without such limitations could change how these disorders are managed. Moreover, the findings would be of substantial significance in developing countries where treatments are often non-existent.
Improved Perception Of Temporal Information In Electrical Signals For Profoundly Deaf Users Of Cochlear Implants
Funder
National Health and Medical Research Council
Funding Amount
$170,440.00
Summary
The ultimate goal of this project is to improve the ability of cochlear implant users to understand speech. The way in which a speech signal varies in amplitude over time provides useful information to the listener about the content of the speech signal. Currently, the way that the acoustic signal amplitude is converted to electrical signal amplitude for cochlear implantees does not take into consideration the very significant loudness summation present in multiple-electrode electrical stimulati ....The ultimate goal of this project is to improve the ability of cochlear implant users to understand speech. The way in which a speech signal varies in amplitude over time provides useful information to the listener about the content of the speech signal. Currently, the way that the acoustic signal amplitude is converted to electrical signal amplitude for cochlear implantees does not take into consideration the very significant loudness summation present in multiple-electrode electrical stimulation. That is, when there are multiple sequential current pulses on different electrodes over a short time, the resultant loudness is greater than the loudness due to individual current pulses. The lack of consideration of loudness summation effects has led to the amplitude variations in the acoustic signal not being accurately represented in the loudness variation perceived by the cochlear implantee. This project aims to develop a practical way of more accurately representing speech signal amplitude fluctuations for cochlear implantees by studying the effects of loudness summation. A second aim of the project is to study the effects on perception of using differently-shaped current pulses from those currently used. There is evidence from physiology experiments that using different shapes might cause the electrical stimulation to activate a more narrowly-spaced set of auditory neurons for each electrode. The application of results of both these studies will lead directly to improved perception of speech and other sounds by cochlear implantees, thus improving their communication ability and quality of life.Read moreRead less
Object Recognition Processes For Motor Output Formation In Visual Agnosic Patients
Funder
National Health and Medical Research Council
Funding Amount
$199,260.00
Summary
Damage to the temporo-occipito-parietal areas of the brain leads to selective impairment in cognitive activities, including motor control and vision. Impaired higher visual processes necessary for object recognition, with intact primary visual functions, is defined as visual agnosia. Experimental work in this disorder has been confined largely to the perceptual aspects, neglecting the functional (motoric) consequences. In a series of kinematic and perceptual experiments, we will require patients ....Damage to the temporo-occipito-parietal areas of the brain leads to selective impairment in cognitive activities, including motor control and vision. Impaired higher visual processes necessary for object recognition, with intact primary visual functions, is defined as visual agnosia. Experimental work in this disorder has been confined largely to the perceptual aspects, neglecting the functional (motoric) consequences. In a series of kinematic and perceptual experiments, we will require patients with visual agnosia to grasp objects presented in unusual perspectives or variable illumination. The findings will enlarge our knowledge in three ways. First, they will clarify how distributed, but parallel object-recognition processes are coordinated for intended action towards a goal. Little is known about how we adapt our actions to object perception. A tool can be viewed from different angles, or as having different functional uses, but currently we are unable to explain how the mental representation influences the motor output to that tool. By studying a disrupted system, as in visual agnosia, we can speculate about the organisation of the intact system. Second, this project has important implications for new rehabilitative approaches for subjects affected by object recognition disorders. Only if we understand more fully the nature of the poor visuo-motor coordination, can we implement more efficient rehabilitative techniques. Finally, this project will also contribute to the classification of visual agnosia. Although it is commonly agreed that all agnosic patients are different, there is no standard taxonomy for the disorder. An instrument is necessary which represents the basic empirical phenomena, and which provides objective distinctions between different syndromes. Kinematic characterisation of the perceptual and motor control dysfunction in visual agnosia may be the key to open the file of this fascinating yet poorly understood disorder.Read moreRead less