The sense of hearing
Cinema in the head
How listening protects us and keeps us healthy
The sense of hearing saves lives, so it will not be turned off when we sleep. We hear the danger and the direction from which it threatens, and bring us to safety in time. Already this alarm system has a social component. Because we do not react only when we perceive the threatening noise itself, but also when others warn us. Our ears are particularly sensitive to what they want to hear: language. Even babies fascinate human voices more than anything else. Even before birth, they get used to hearing their mother, because from the 20th week of pregnancy, the inner ear is the first organ of our body completely trained. And as patients with near-death experiences report, our lives often end with acoustic impressions. Listening means safety and closeness first. When I hear others, I am not alone.
But listening is also communication. Our language marks a cognitive quantum leap of evolution, through which we are more than monkeys with great brains: "The incarnation took place through hearing," explains Professor Henning Scheich, head of the Leibniz Institute for Neurobiology in Magdeburg. We want to hear and be heard. That is the basis of every human relationship. When our ancestors gathered around the fire in the evening to share experiences and stories, togetherness was self-evident. We are increasingly lost to her. We hear more and more, but less and less - and less often together. But without conversation and exchange with each other, we feel alone and unhappy, even when we are constantly surrounded by people. Not only listening, but proper listening is therefore a prerequisite for social interaction - and apparently also for healthy brain functions. Neurobiologist Henning Sheikh has found that brain activity in hearing is much more variable than in vision.
So, one and the same sound deals with the left and then the right brain, depending on which thoughts we associate with it. For sounds, unlike objects, are only symbolic and must first be interpreted. We gather experiences, form categories and develop an idea of what we hear. By contrast, visual information requires and encourages our brain much less: if you watch television, you hardly need imagination. Listening produces cinema in the mind. And because we store the images, we also have certain sonic expectations and are irritated if they do not meet. If a door clatters into the lock, we do not feel safe in the apartment behind it. A razor for women should be discreetly quiet, for men he must let the stubble speak neatly. Acoustician Friedrich Blutner, who built musical instruments before devoting himself to sound design, believes that the preferred sounds also express the lifestyle of a generation. Today products have to crack and crack, so that we find them good: performance is often equated with volume. Should our life relax more, we will probably appreciate softer sounds.
What affects the sense?
Everything that is too loud and too shrill
If too strong sound waves burn over the hairs of the auditory cells, they can break off or break. Such blast traumas are caused by volumes from about 130 decibels, so by New Year's bulls, but also toy pistols. The damage is final, because the cells of the inner ear do not renew themselves. In the long run, sound below the threshold of pain already destroys the ear, and the faster, the louder it is. Often we do not notice anything at first. "These small damages add up, until at some point the point of no return is exceeded," warns Dr. Birgit Mazurek, head of the Tinnitus Center of the Berlin Charité.
Noise, neither our ear nor our body gets used to noise. For him, noise means stress: cortisol is secreted, and blood pressure rises. Living in a noisy environment increases women's risk of heart attack more than threefold, according to a Charité study. And at night our ears are even more sensitive: according to a study by the Robert Koch Institute, nocturnal 55 decibels - this value is reached on many of our roads - increase the risk of hypertension, elevated blood lipid levels and asthma.
The power of music
How we can use our hearing to heal ourselves
Even our brain unconsciously sings when we hear happy songs. Responsible for this are mirror neurons that start, no matter whether we do something ourselves or observe others in their actions. For example, pianists have the same brain areas when listening to piano music as if they were playing themselves.And even non-musicians have nerve cells that communicate with the larynx - and sing or whistle silently. "First comes the music, then the language," says Dr. Stefan Koelsch, Head of the Research Group Neurocognition of Music at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig. When listening to music, it is primarily areas of the brain that are not under our control that affect our nervous, hormonal and immune systems. Research shows that blood pressure, heart rate and respiratory rate decrease as we listen to quiet sounds. This works regardless of whether we like the piece at all. But music as a medicine can do much more: it lowers, for example, the fear of and during a medical intervention such as a gastroscopy. Yale University researchers found that patients need even less anesthetic
They listen to their favorite music. And this is actually because of the music and not because it drowns out operating room sounds. Other studies have shown that people recover faster and require less painkillers when they wake up after surgery with music. Gentle music also dampens the sensation of pain during labor. And premature babies, who were played several times daily sleep and nursery rhymes, gained weight faster and were able to be discharged earlier from the intensive care unit. "We are just beginning to understand how exactly music works in the body," explains Stefan Koelsch. "But in the future, music will be used more and more often in medicine." Of course, music also heals when used actively. Heidelberg therapists were able to prove that regular music making reduces the frequency of migraine attacks in children even more effectively than special drugs. In dementia patients, songs can bring back forgotten memories and words, Parkinson's disease helps the rhythm to coordinate their movements, and stroke patients often find talk about singing back to speech.
What if the sense is disturbed?
Hearing aids are embarrassing for many. They make us smart
With around 15 million people affected, hearing loss is a widespread disease in Germany. One reason for this is the higher life expectancy, another is the permanent noise overload. The number of tin-nitus patients is also growing, and acute hearing loss is increasingly affecting young people (see box).
Hearing problems should be treated as early as possible. Anyone who listens badly for a long time forgets more and more sounds and has to learn them afresh. The psychologist Siegfried Lehrl from the University of Erlangen has been able to prove that people improve in an IQ test as soon as they get hearing aids - and their mental capacity is no longer absorbed by the acoustic understanding. While hearing aids amplify sound, cochlear implants (tiny hearing prostheses in the inner ear) directly stimulate the auditory nerve via electrodes. The prerequisite for their use is that this nerve still works: this is the case, for example, with adults who are deaf after an acute hearing loss, or with many deaf-born children.
About two in every 1,000 newborns are affected by congenital hearing disorders. In childhood, it is even more important to recognize and treat these disorders in a timely manner. Because there are sensitive phases for the development of the ear and above all the language. Sometimes something that has been missed can hardly or not at all be made up for.
How to keep your hearing fit
We can not increase the function of the inner ear, but only preserve it. But training can be the processing of hearing in the brain. This is often part of a therapy of tinnitus and hearing loss, but can also be used preventively. "Well-trained hearing is much more likely to eliminate small damage," says Dr. Gerhard Hesse, chief physician of the psychosomatic clinic in Bad Arolsen. So it's worth choosing carefully what we hear - and occasionally stopping your hearing: - CLOSE EYES and listen to everyday life. In the park or in the bus. What are you listening to? And from which direction do the sounds come from? - ENJOY MUSIC. Acoustic irrigation rather reduces the perception of hearing in the brain, but deliberate listening trains it. Concentrate for example once only on a single instrument. - GET YOUR EARS REST. When you have been exposed to special noise, your hearing takes time to recover. - PROTECT YOUR HEARING FROM CRASH. Deafness and earbuds after a concert are first warning signs, even if they have disappeared the next morning. Ear plugs, for example, relieve the strain on the ear: they attenuate by 15 to 30 decibels and still allow enough music enjoyment.
Tinnitus or hearing loss?
In Germany, around three million people suffer from ear noises. Swollen or inflamed auditory cells automatically send signals to the brain. Tinnitus often occurs after noise overload and can be treated by infusion therapy or medication.However, if the tinnitus persists for more than three months, this promotion of circulation no longer makes sense: the tinnitus activity is then fixed in the brain. "Therapy is about learning how to walk away", explains tinnitus expert Dr. med. Birgit Mazurek, ENT doctor at the Berlin Charite. Many sufferers are particularly affected by the noise because they focus their entire perception on it. On the other hand, if you suddenly hear badly, you may be suffering from a hearing loss and should go to the doctor no later than on the second day. Because the cause is often a kind of inner ear infarction, and the sensory cells can die if the therapy does not start on time. A sudden loss of hearing can have various causes, as Birgit Mazurek explains: "Stress is often a contributory cause."
