Successfully prevent hearing damage

The most important facts in brief

• Very high or permanently excessive sound levels when using smartphones with headphones, frequent visits to clubs and concerts and toys with bangs and sound effects can damage the hair cells in the inner ear.
• Noise-induced hearing loss usually develops gradually and as a result of frequent and repeated noise overload.
• Typical symptoms such as tinnitus and hearing loss often disappear at first, but remain permanent after a certain stage of damage.
• Noise-induced hearing loss cannot be cured.
• Prevention is key: It is important to avoid sound sources above 85 decibels in the long term, for example by 1) Using noise-reduced toys, players and headphones 2) Volume apps and a noise diet with active breaks 3) Mechanical hearing protection with ear defenders

A slight ringing in the ears is nothing new for 16-year-old Manuel after a visit to the club. Normally, however, the spook is over after a few hours. But this time the annoying beeping just won't go away.

«Persistent tinnitus noises in the ear are a typical sign of incipient hearing damage caused by noise,» says Christof Stieger, Head of Audiology at the ENT Clinic at the University Hospital Basel. «It doesn't matter whether the previous sound was perceived as a pleasure or a disturbance.»

How the sound gets into the brain

To understand how hearing damage is caused by noise, you need to know how hearing works. Every noise generates sound waves. These sound waves enter the auditory canal via the pinna and cause the eardrum at the end to vibrate. These movements are picked up by the ossicles in the middle ear, amplified and passed on to the cochlea, the cochlea in the inner ear.

The cochlea is a fluid-filled organ that is lined with thousands of fine hair cells. These highly sensitive hair cells in turn pick up the incoming mechanical vibrations and convert them into electrical impulses, which they pass on to the auditory nerve. Finally, the auditory nerve transmits the impulses to the brain, where they are processed accordingly.

Unfortunately, your own feelings are of little help in judging the right volume: subjective noise tolerance depends on personal preferences.

Hearing is therefore a highly complex and finely tuned process that can be disrupted at various points. The hair cells in the cochlea are particularly susceptible to interference. They are very sensitive in order to perceive and transmit even the finest nuances in the sound spectrum.

These fine structures are correspondingly vulnerable if they are exposed to excessive or prolonged sound pressure. This happens when the ear is exposed to an extremely loud noise, such as a bang, over a short period of time or persistently loud noises, such as music played at full volume, over a longer period of time.

Mechanical overload and long-term metabolic damage to the hair cells are often the result.

How noise causes irreversible damage to hair cells

«This process can be visualised particularly well if you imagine the area of the hair cells as a field of grain over which the sound sweeps like a storm,» says Stieger. «Depending on how long and how strong the storm rages, the stalks are then pushed to one side or even completely snapped off.»

Slightly damaged hair cells can recover after a period of rest. «Completely broken hair cells, on the other hand, are irretrievably destroyed and can no longer fulfil their function,» says Stieger.

This always affects the high-pitched sounds first. «This is because the hair cells for this sound range are located at the entrance to the cochlea and are therefore subject to particularly high mechanical stress,» says the audiologist.

Ringing in the ears is always an alarm signal

«Mild hearing damage in the high-frequency range goes largely unnoticed at first and can only be detected in a hearing test,» says ear expert Stieger. «Tinnitus noises such as ringing, whistling, humming or a numb, wobbly feeling in the ear are more noticeable. Such complaints usually disappear again after a period of rest, but still leave their mark.» This is because any overload weakens the hair cells in the long term.

«It's a cumulative effect that develops gradually,» says Stieger. «The longer and stronger the exposure to noise and the greater the stress on the hair cells, the less well they can recover afterwards and the earlier permanent hearing problems such as permanent tinnitus and noticeable noise-induced hearing loss can occur.»

If annoying ringing in the ears persists 24 hours after the noise event, you should see a doctor, advises hearing specialist Stieger. «Medically, however, there is little that can be done about the annoying ringing in the ears, as damaged hair cells do not grow back and cannot be repaired from the outside.»

For the same reason, noticeable hearing loss caused by noise cannot be treated causally. «In certain cases, hearing aids can help to compensate for existing deficits,» says Stieger. «There are also various ways to make tinnitus more subjectively bearable so that you can cope with it better - but hearing damage caused by noise cannot really be cured.»

«100 decibels, as they affect the ear in clubs, are harmless for just ten minutes,» says hearing expert Tanja Kampus.

The be-all and end-all against premature noise-induced hearing loss is therefore prevention - and protecting your hearing from too much sound. Loudness is measured by the sound level that affects the ear and is expressed in decibels (dB). An increase of ten decibels describes a subjectively perceived doubling of the volume. «A conversation from one metre away has about 70 decibels,» says Stieger. «A lorry passing ten metres away already reaches the ear at around 80 decibels, a jackhammer at 100 and a siren at 110 decibels. Headphones sometimes reach 80 to 100 decibels.»

«Whether a noise is harmful to the ear depends not only on its volume but also on the duration of exposure to the sound,» says Tanja Kampus, a paediatric acoustician from Baden in Aargau. «We know from occupational medicine that an adult's hearing can withstand noise exposure of 85 decibels for up to eight hours a day during a 40-hour working week without suffering any damage.»

If noise exposure rises to 95 decibels, the risk-free time for the ear is already reduced to 48 minutes per working day. «100 decibels, as experienced in clubs or through headphones, is harmless to the ear for just ten minutes,» emphasises Kampus.

Unfortunately, your own instincts are of little help when it comes to assessing the right volume, as subjective noise tolerance depends heavily on personal preferences. As a general rule, anything in the range of room volume - i.e. from around 70 to 80 decibels - is harmless; anything above this depends on the volume level and the duration of exposure to the sound.

«Toys with music or other sound effects can be very loud, which is why I advise parents to look out for a labelled noise reduction of up to 85 decibels when buying them,» says Kampus. «Toy weapons such as squib guns, but also the classic cracking frogs and squeaky animals, which do not have a throttle, should also never be used near the head, as they can cause impulse noises of over 100 decibels.» The same applies to New Year's Eve fireworks and firecrackers.

«When buying headphones that are often used for hours a day, you can also look out for models with noise reduction,» says the paediatric acoustician. «So-called capsule headphones or headphones with additional noise cancellation that reduce or block out disturbing ambient noise are also useful.»

How we can protect our hearing

To sensitise teenagers and young people to the issue of noise pollution, volume apps for smartphones have proven their worth, providing reliable information about how loud the current ambient noise is at all times.

«When visiting very loud places such as indoor playgrounds, go-kart tracks, open-air concerts or clubs, it also helps to take short breaks in quieter areas, for example at the bar or outside, and then give your ears plenty of quiet time to recover,» recommends hearing acoustician Kampus. Last but not least, you can protect your ears from loud ambient noise with mechanical hearing protection.

«The cheapest option is foam earplugs, which dampen noise by around 10 decibels. They cost a few francs, but are not very comfortable to wear and distort the sound,» says Kampus. «Lamellar earplugs made of silicone are much more comfortable, can be reused several times and achieve an attenuation effect of up to 20 decibels.»

For children and young people who are regularly exposed to high levels of external noise because they play in an orchestra or band, like to go to clubs and concerts or even work in a music bar, it is worth buying professional hearing protection, says Kampus: «These are relatively expensive, customised earplugs that use filters to provide linear attenuation with sufficient protection and good sound.» All in all, it is relatively easy to avoid hearing damage caused by noise without having to miss out on hip events, intense music enjoyment and the fun of partying.