Monthly Archives: August 2018

How the inner ear works

“This helps us understand the mechanisms that enable us to perceive speech and music. We hope that more knowledge about the capabilities of the ear will lead to better treatments for the hearing impaired,” says Anders Fridberger, professor of neuroscience at Linköping University.

To perceive speech and music, you must be able to hear low-frequency sound. And to do this, the brain needs information from the receptors, which are located close to the top of the cochlea, the spiral cavity in the inner ear. This part of the inner ear is difficult to study, as it is embedded in thick bone that is hard to make holes in, without causing damage. Now the international research team has been able to measure, in an intact inner ear, how the hearing organ reacts to sound. The results have been published in PNAS, the Proceedings of the National Academy of Sciences.

To measure in the hearing organ, the researchers used optical coherence tomography, a visualization technology for biological matter that is often used to examine the eye.

“We have been able to measure the inner ear response to sound without having to open the surrounding bone structures and we found that the hearing organ responds in a completely different way to sounds in the voice-frequency range. It goes against what was previously thought of how the inner ear works.

Beat of music automatically

imWhat most people call the sense of rhythm — the mechanism that enables us to clap along or dance to music — is an intangible ability that is exclusive to human beings. For example, imagine a barrel before it is placed inside a barrel organ. On the barrel, you can see exactly which tones will be played and for how long they will be audible. However, the regularity of the rhythm cannot be read on the barrel. This rhythm exists only in our heads, where our brain recognises patterns in the sounds. This helps us to predict the music, enabling us to synchronise our actions with it, i.e. dancing, clapping, singing or playing the violin.

Swaying back and forth

Human beings are the only species that recognise these patterns and scientists suspect that an evolutionary development is at the root of it. Music can work as a social lubricant within a community and a sense of rhythm enables us to make music with others or sway back and forth on the bleachers of a football stadium.

For five years, Fleur Bouwer plumbed the depths of the human sense of rhythm in order to map out the fundamental brain processes that lie at its roots. She discovered that both training — i.e. music lessons — and concentration — i.e. paying attention to the music — are unnecessary in recognising rhythm. Even the brains of untrained listeners can recognise the rhythm of a piece of music, even when performing a completely different task.

However, the PhD candidate would like to dispel one misunderstanding: the fact that nearly everyone is capable of recognising musical rhythm does not mean that everybody can dance to that rhythm. ‘This requires more complex motor skills on top of the ability to recognise the rhythm, and unfortunately these skills are not as universal to humans as the sense of rhythm.’

Parkinson’s disease

Although training and attention are not necessary for picking up rhythm, they do help. Professional musicians have been shown to be better than normal people at predicting notes in a rhythm based on the rhythm they recognised in an excerpt of music. This ability was its strongest when the musicians were concentrating hard. Bouwer: ‘My results show that, to a certain extent, the sense of rhythm is a fundamental brain process that develops unconsciously. However, training may well help you to make predictions based on the rhythm. This is useful when playing music or dancing.’

Bouwer hopes that knowledge of musical perception can ultimately be used to help people. ‘The brain scanner displays activity in the motor networks when people listen to music with a clearly discernible rhythm. I find that particularly interesting. Maybe we can eventually use this relationship between musical experience and the motor system to help people with motor-system disorders such as Parkinson’s disease. However, before we explore this possibility, we must gain a better understanding of the fundamental processes. My research contributes to this.’

On 7 June, a symposium will be held to mark the conferral of Bouwer’s doctorate, at which international scientists will share new insights into sense of rhythm and the brain.

You know that Music demonstrated to alleviate cancer

A systematic review published by the Cochrane Library found that there is significant evidence that music interventions help alleviate symptoms of anxiety, pain and fatigue in cancer patients, while also boosting their quality of life.

Led by Joke Bradt, PhD, associate professor in Drexel University’s College of Nursing and Health Professions, a team looked into studies that examined the impact of music therapy (a personalized music experience offered by trained music therapists) and music medicine (listening to pre-recorded music provided by a doctor or nurse) on psychological and physical outcomes in people with cancer.

“We found that music therapy interventions specifically help improve patients’ quality of life,” explained Bradt. “These are important findings as these outcomes play an important role in patients’ overall well-being.”

A total of 52 trials were examined in the review, constituting of 3,731 participants with cancer. Twenty-three of the trials were categorized as music therapy and the remaining 29 were classified as music medicine interventions.

Overall, one of the most impactful findings was that music interventions of all kinds resulted in a moderate-to-strong effect in reducing patients’ anxiety.

When it came to pain reduction, the researchers found a large treatment benefit; for fatigue, a small-to-moderate treatment effect was found.

Small reductions in heart and respiratory rates, as well as lowered blood pressure, were also linked to music interventions.

“The results of single studies suggest that music listening may reduce the need for anesthetics and analgesics, as well as decreased recovery time and duration of hospitalization, but more research is needed for these outcomes,” according to Bradt and her co-authors.

When comparing music therapy to music medicine, the team saw a moderate increase in patients’ quality of life when music therapy was applied. There was not a similar effect in the case of music medicine interventions.

“Both music medicine and music therapy interventions play an important role in cancer care but we didn’t quite know yet which interventions may be best suited for which type of outcome,” Bradt said.

In light of the benefits to cancer patients’ quality of life, and specifically their levels of anxiety, pain and fatigue, the researchers hope music interventions will become more widespread.

“We hope that the findings of this review will encourage health care providers in medical settings to seriously consider the use of music therapy in the psychosocial care of people with cancer,” Bradt said.