Nav: Home

Heart rate variation due to stress affects auditory attention

June 06, 2019

Sudden hearing loss can be experienced in highly stressful situations, usually lasting a short time. Researchers at São Paulo State University (UNESP) in Brazil, collaborating with colleagues at Oxford Brookes University in the United Kingdom, have reported a discovery that contributes to a deeper understanding of this phenomenon.

According to a study by the group published in Scientific Reports, brain activity related to auditory attention keeps pace with heart rate. Stress-induced changes in heart rate may therefore impair auditory perception. This finding offers new perspectives for the treatment of attention and communication disorders.

The study was supported by São Paulo Research Foundation - FAPESP. Brazilian scientists affiliated with the University of São Paulo (USP) and ABC Medical School (FMABC) also took part.

"We found that even quite low levels of stress can affect heart rate and impair auditory attention," Vitor Engrácia Valenti told.

According to Valenti, a professor at the UNESP campus in Marília and principal investigator for the study, recent research had already shown that heart rate can fluctuate in response to auditory stimulation and that these variations are controlled by the vagus nerve.

"However, exactly how auditory stimuli influence heart rate control by the vagus nerve was poorly understood," Valenti said. "In addition, it wasn't clear whether heart rate control interacted with the cortical brain activity associated with auditory attention in humans."

The vagus nerve extends from the brainstem down to the abdomen and is part of the autonomic nervous system that controls unconscious bodily processes such as heart rhythm, breathing and digestion. An overactive vagus nerve can result in an abnormally low heart rate.

Previous studies with animals showed that vagal activity increases during relaxing auditory stimulation and boosts the expression of a protein called c-Fos in the auditory cortex. These findings pointed to an association between cortical sound processing and the parasympathetic nervous system, Valenti explained.

The researchers set out to investigate these interactions by means of an experiment with 49 women in which heart rate regulation was challenged by a mildly stressful language test.

The participants were asked to say as many Portuguese words beginning with 'A' as they could in 60 seconds, without repetition or inflections such as the diminutive.

The time limit was considered necessary to avoid interference in the volunteers' brain activity either by the sympathetic nervous system - which regulates responses to stress, such as heart rate acceleration via the effects of adrenaline - or the release of cortisol.

Heart rate and auditory processing were measured before and after the language test. The integrity of the auditory pathway in the brain was verified electrophysiologically using a standard procedure called long-latency auditory evoked potential (P300).

Heart rate variability is an indicator of autonomic cardiac control in response to different levels of stress. The P300 test was used in this study to analyze auditory attention to a sound stimulus by monitoring the prefrontal cortex and auditory cortex activity via electrodes placed on the forehead, cranial vertex and earlobes.

The results of the tests showed that the relatively mild stress to which the volunteers were subjected was sufficient to alter their heart rate and that this happened in parallel with an attenuation of their auditory attention.

Statistical analyses, including correlations and linear regression models, indicated a weak but significant association between autonomic control of the heart by the vagus nerve and auditory processing in the brain.

"This suggests that auditory information is processed less well in stressful than calm situations," Valenti said.

"It's possible that if you breathe more slowly under stress, for example, the parasympathetic nervous system may slow your heart rate and improve your auditory perception."

According to Valenti, the findings suggest novel possibilities for the treatment of patients with attention and communication disorders based on vagus nerve activation by electrical stimulation in the auricular region to control heart rate.

Studies of autistic children conducted by researchers at UNESP Marília's Phonoaudiology Department have used this method and achieved promising results.

"The data from these studies shows a significant improvement in the symptoms of children with autism as a result of this treatment method," Valenti said.
-end-
About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at http://www.fapesp.br/en and visit FAPESP news agency at http://www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

Fundação de Amparo à Pesquisa do Estado de São Paulo

Related Stress Articles:

How stress remodels the brain
Stress restructures the brain by halting the production of crucial ion channel proteins, according to research in mice recently published in JNeurosci.
Why stress doesn't always cause depression
Rats susceptible to anhedonia, a core symptom of depression, possess more serotonin neurons after being exposed to chronic stress, but the effect can be reversed through amygdala activation, according to new research in JNeurosci.
How plants handle stress
Plants get stressed too. Drought or too much salt disrupt their physiology.
Stress in the powerhouse of the cell
University of Freiburg researchers discover a new principle -- how cells protect themselves from mitochondrial defects.
Measuring stress around cells
Tissues and organs in the human body are shaped through forces generated by cells, that push and pull, to ''sculpt'' biological structures.
Cellular stress at the movies
For the first time, biological imaging experts have used a custom fluorescence microscope and a novel antibody tagging tool to watch living cells undergoing stress.
Maternal stress at conception linked to children's stress response at age 11
A new study published in the Journal of Developmental Origins of Health and Disease finds that mothers' stress levels at the moment they conceive their children are linked to the way children respond to life challenges at age 11.
A new way to see stress -- using supercomputers
Supercomputer simulations show that at the atomic level, material stress doesn't behave symmetrically.
Beware of evening stress
Stressful events in the evening release less of the body's stress hormones than those that happen in the morning, suggesting possible vulnerability to stress in the evening.
How plants cope with stress
With climate change comes drought, and with drought comes higher salt concentrations in the soil.
More Stress News and Stress Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.