A new study on musical hallucination gives clues onto why the brain would produce made-up melodies. Musical hallucination is when songs or music is being heard in a patients head even though there is no music. It can convince people that there is a violin quartet playing outside their house, even though there is no quartet. People with this conditionally are typically psychologically normal but have a condition where they hear musical hallucinations.
The case of Sylvia, described in this article, was submitted to Cortex journal. The study was conducted doctors at a London neurological clinic. They were able to compare her brain activity when she had both quiet and loud hallucinations. This had yet to be done in a study, and the comparison would give important clues as to why the brain has musical hallucinations. The results of this study aren't concrete as it only involved one person, but a broader study with similar results could indicate many things.
The study was based on the idea that musical hallucinations could sometimes be stopped by real music. In the case of Sylvia, listening to Bach would give her a few seconds of relief, and then the hallucinations would slowly start up again. Using this knowledge, the scientists measured her brain activity. When Bach stopped playing, Sylvia would press numbers on a keyboard to rate her hallucination in strength. A scanner would record her brain activity during the variation of hallucinations.
The study found that when the hallucinations were louder, stronger brain waves were consistently produced in certain regions of the brain. These regions are what every human uses when we listen to music. Based on a theory that our brains generate predictions about what is going to happen next, the scientists suggest that having hearing loss contributes to musical hallucinations. With less auditory signals entering the brain, error detection becomes weaker. So the regions of the brain that process music make faulty predictions and those predictions grow stronger until they feel real. This study is being run on more people to get accurate data, but Sylvia's musical hallucinations proved to be an interesting starting point for research.
Nature and Science Themes
- Science is based on evidence (Sylvia's study makes an interesting point but more research is needed to back it up)
- Role of skepticism (Not thinking that the results from this study are 100% correct and apply to everyone with musical hallucinations)
- Role of motivation and curiosity (Finding out why musical hallucinations occur
I recently watched a Ted Talk on Charles Bonnet syndrome. A neurologist was saying that people with impaired senses are more likely to develop hallucinations relating to that sense.
ReplyDelete