Posts tagged auditory hallucinations
Articles and news from the latest research reports.
Brain circuit problem likely sets stage for the “voices” that are symptom of schizophrenia
St. Jude Children’s Research Hospital scientists have identified problems in a connection between brain structures that may predispose individuals to hearing the “voices” that are a common symptom of schizophrenia. The work appears in the June 6 issue of the journal Science.
(Image: Getty Images)
Researchers linked the problem to a gene deletion. This leads to changes in brain chemistry that reduce the flow of information between two brain structures involved in processing auditory information.
The research marks the first time that a specific circuit in the brain has been linked to the auditory hallucinations, delusions and other psychotic symptoms of schizophrenia. The disease is a chronic, devastating brain disorder that affects about 1 percent of Americans and causes them to struggle with a variety of problems, including thinking, learning and memory.
The disrupted circuit identified in this study solves the mystery of how current antipsychotic drugs ease symptoms and provides a new focus for efforts to develop medications that quiet “voices” but cause fewer side effects.
“We think that reducing the flow of information between these two brain structures that play a central role in processing auditory information sets the stage for stress or other factors to come along and trigger the ‘voices’ that are the most common psychotic symptom of schizophrenia,” said the study’s corresponding author Stanislav Zakharenko, M.D., Ph.D., an associate member of the St. Jude Department of Developmental Neurobiology. “These findings also integrate several competing models regarding changes in the brain that lead to this complex disorder.”
The work was done in a mouse model of the human genetic disorder 22q11 deletion syndrome. The syndrome occurs when part of chromosome 22 is deleted and individuals are left with one rather than the usual two copies of about 25 genes. About 30 percent of individuals with the deletion syndrome develop schizophrenia, making it one of the strongest risk factors for the disorder. DNA is the blueprint for life. Human DNA is organized into 23 pairs of chromosomes that are found in nearly every cell.
Earlier work from Zakharenko’s laboratory linked one of the lost genes, Dgcr8, to brain changes in mice with the deletion syndrome that affect a structure important for learning and memory. They found evidence that the same mechanism was at work in patients with schizophrenia. Dgcr8 carries instructions for making small molecules called microRNAs that help regulate production of different proteins.
For this study, researchers used state-of-the-art tools to link the loss of Dgcr8 to changes that affect a different brain structure, the auditory thalamus. For decades antipsychotic drugs have been known to work by binding to a protein named the D2 dopamine receptor (Drd2). The binding blocks activity of the chemical messenger dopamine. Until now, however, how that quieted the “voices” of schizophrenia was unclear.
Working in mice with and without the 22q11 deletion, researchers showed that the strength of the nerve impulse from neurons in the auditory thalamus was reduced in mice with the deletion compared to normal mice. Electrical activity in other brain regions was not different.
Investigators showed that Drd2 levels were elevated in the auditory thalamus of mice with the deletion, but not in other brain regions. When researchers checked Drd2 levels in tissue from the same structure collected from 26 individuals with and without schizophrenia, scientists reported that protein levels were higher in patients with the disease.
As further evidence of Drd2’s role in disrupting signals from the auditory thalamus, researchers tested neurons in the laboratory from different brain regions of mutant and normal mice by adding antipsychotic drugs haloperidol and clozapine. Those drugs work by targeting Drd2. Originally nerve impulses in the mutant neurons were reduced compared to normal mice. But the nerve impulses were almost universally enhanced by antipsychotics in neurons from mutant mice, but only in neurons from the auditory thalamus.
When researchers looked more closely at the missing 22q11 genes, they found that mice that lacked the Dgcr8 responded to a loud noise in a similar manner as schizophrenia patients. Treatment with haloperidol restored the normal startle response in the mice, just as the drug does in patients.
Studying schizophrenia and other brain disorders advances understanding of normal brain development and the missteps that lead to various catastrophic diseases, including pediatric brain tumors and other problems.
(Source: stjude.org)
Neurologists Report Unique Form of Musical Hallucinations
Case raises intriguing questions about memory and forgetting
One night when she was trying to fall asleep, a 60-year-old woman suddenly began hearing music, as if a radio were playing at the back of her head.
The songs were popular tunes her husband recognized when she sang or hummed them. But she herself could not identify them.
This is the first known case of a patient hallucinating music that was familiar to people around her, but that she herself did not recognize, according to Dr. Danilo Vitorovic and Dr. José Biller of Loyola University Medical Center. The neurologists describe the unique case in the journal Frontiers in Neurology.
The case raises “intriguing questions regarding memory, forgetting and access to lost memories,” the authors write.
Musical hallucinations are a form of auditory hallucinations, in which patients hear songs, instrumental music or tunes, even though no such music is actually playing. Most patients realize they are hallucinating, and find the music intrusive and occasionally unpleasant. There is no cure.
Musical hallucinations usually occur in older people. Several conditions are possible causes or predisposing factors, including hearing impairment, brain damage, epilepsy, intoxications and psychiatric disorders such as depression, schizophrenia and obsessive-compulsive disorder. Hearing impairment is the most common predisposing condition, but is not by itself sufficient to cause hallucinations.
Vitorovic and Biller describe a hearing-impaired patient who initially hallucinated music when she was trying to fall asleep. Within four months, she was hearing music all the time. For example, she would hear one song over and over for three weeks, then another song would begin playing. The volume never changed, and she was able to hear and follow conversations while hallucinating the music.
The patient was treated with carbamazepine, an anti-seizure drug, and experienced some improvement in her symptoms.
The unique feature of the patient was her ability to hum parts of some tunes and recall bits of lyrics from some songs that she did not even recognize. This raises the possibility that the songs were buried in her memory, but she could not access them except when she was hallucinating.
“Further research is necessary on the mechanisms of forgetfulness,” Vitorovic and Biller write. “In other words, is forgotten information lost, or just not accessible?”
(Image: Marten Blom)
Avatar therapy helps silence voices in schizophrenia
An avatar system that enables people with schizophrenia to control the voice of their hallucinations is being developed by researchers at UCL with support from the Wellcome Trust.
The computer-based system could provide quick and effective therapy that is far more successful than current pharmaceutical treatments, helping to reduce the frequency and severity of episodes of schizophrenia.
In an early pilot of this approach involving 16 patients and up to seven, 30 minute sessions of therapy, almost all of the patients reported an improvement in the frequency and severity of the voices that they hear. Three of the patients stopped hearing voices completely after experiencing 16, 13 and 3.5 years of auditory hallucinations, respectively. The avatar does not address the patients’ delusions directly, but the study found that they do improve as an overall effect of the therapy.
The team has now received a £1.3 million Translation Award from the Wellcome Trust to refine the system and conduct a larger scale, randomised study to evaluate this novel approach to schizophrenia therapy which will be conducted at King’s College London Institute of Psychiatry.
The first stage in the therapy is for the patient to create a computer-based avatar, by choosing the face and voice of the entity they believe is talking to them. The system then synchronises the avatar’s lips with its speech, enabling a therapist to speak to the patient through the avatar in real time. The therapist encourages the patient to oppose the voice and gradually teaches them to take control of their hallucinations.
Julian Leff, Emeritus Professor in UCL Mental Health Sciences, developed the therapy and is leading the project. He said: “Even though patients interact with the avatar as though it was a real person, because they have created it, they know that it cannot harm them, as opposed to the voices, which often threaten to kill or harm them and their family. As a result the therapy helps patients gain the confidence and courage to confront the avatar, and their persecutor.
“We record every therapy session on MP3 so that the patient essentially has a therapist in their pocket which they can listen to at any time when harassed by the voices. We’ve found that this helps them to recognise that the voices originate within their own mind and reinforces their control over the hallucinations.
The larger-scale study will begin enrolling the first patients in early July. The team are currently training the therapists and research staff to deliver the avatar therapy and finalising the study set-up. The first results of this larger study are expected towards the end of 2015.
Professor Thomas Craig of King’s College London Institute of Psychiatry, who will lead the larger trial, said: “Auditory hallucinations are a very distressing experience that can be extremely difficult to treat successfully, blighting patients’ lives for many years. I am delighted to be leading the group that will carry out a rigorous randomised study of this intriguing new therapy with 142 people who have experienced distressing voices for many years.
“The beauty of the therapy is its simplicity and brevity. Most other psychological therapies for these conditions are costly and take many months to deliver. If we show that this treatment is effective, we expect it could be widely available in the UK within just a couple of years as the basic technology is well developed and many mental health professionals already have the basic therapy skills that are needed to deliver it.”
Schizophrenia affects around 1 in 100 people worldwide, the most common symptoms being delusions (false beliefs) and auditory hallucinations (hearing voices). The illness often has a devastating effect, making it impossible to work and to sustain social relationships. Even with the most effective anti-psychotic medication, around one in four people with schizophrenia continue to suffer from persecutory auditory hallucinations, severely impairing their ability to concentrate.
Current guidelines from the National Institute for Health and Care Excellence (NICE) recommend that schizophrenia is treated using a combination of medication and talking therapies, such as cognitive behavioural therapy. However, fewer than one in ten patients with schizophrenia in the UK have access to this kind of psychological therapy.
Ted Bianco, Director of Technology Transfer and Acting Director of the Wellcome Trust, said: “At a time when many companies have become wary about investing in drug discovery for mental health, we are delighted to be able to facilitate the evaluation of an alternative approach to treatment based on the fusion of a talking therapy with computer-assisted ‘training’.
“In addition to the attraction that the intervention is not reliant on development of a new medication, the approach has the benefit of being directly testable in patients. Should the results of the trial prove encouraging, we expect there may be further applications of the basic strategy worth exploring in other areas of mental health.”
Help at hand for schizophrenics
Researchers from the Bergen fMRI Group at the University of Bergen (UiB) are working on how to help schizophrenics, who hear voices. The way they do this is by studying people who also hear voices, but who do not suffer from a mental illness. For a five-year period, the group is studying the brain processes causing people to hear voices. A recent report published in Frontiers in Human Neuroscience shows some of the group’s startling results.
– We have found that the primary auditory cortex of healthy people who hear voices, responds less to outside stimulus than the corresponding area of the brain in people who don’t hear voices, says Post Doctor Kristiina Kompus.
Kompus, who works at UiB’s Department of Biological and Medical Psychology, is lead author of the just published study.
Variations in cognitive control
The primary auditory cortex is the region of the brain that processes sound. Kompus’ study shows that healthy people who hear voices share some attributes with schizophrenics, as the cortical region in both groups reacts less to outside stimulus.
However, there is an important difference between people who hear voices. Whilst those with schizophrenia have a reduced ability to regulate the primary auditory cortex using cognitive control, those who hear voices but are healthy are able to do so.
– Because of this cognitive control, healthy people who hear voices are able to direct their attention outwards. This sets them apart from schizophrenics, who have a tendency to direct their attention inwards due to their decreased ability to regulate their primary auditory cortex, says Kompus before adding.
– These discoveries have brought us one step close to understanding the hallucinations of schizophrenics and why the voices become a problem for some people but not for others.
Many healthy people hear voices
So what is the next step for Kompus and her fellow researchers?
– We will do further research on the brain structure of people with auditory hallucinations. In particular, we wish to look at the brain’s networks that process outside voices. This is to establish whether these voice hallucinations and the outside voices occur in the same parts of the brain. We also wish to establish if hearing voices is a genetical trait, she says.
According to the researchers, approximately five per cent of us hear voices in the head, even if otherwise healthy. This number is based on research from several countries and surveys. For their own research, Kompus and her team used local media in Bergen to call for people who hear voices. The results were overwhelming, with around 30 people getting in touch with the researchers to register for the study.