Prof. E. Lesinskas. Photo: VU MF
Hearing is a sense that we do not pay much attention to before it is impaired or, in other words, we start to be worried about it when we notice that we do not hear as well as we did before. So what factors may contribute to impaired hearing? How can hearing be protected? And finally, are there ways to restore damaged hearing? We discussed this issue with Prof. Eugenijus Lesinskas, an otorhinolaryngologist (ENT surgeon), and Head of the Centre for Diseases of the Ear, Nose and Throat of Vilnius University Hospital Santaros Klinikos.
Noise is probably the most common cause of hearing impairment
“The functioning of the hearing organ can be damaged by many different factors: noise, pollution, medication or viral diseases. Under the impact of these factors, the sensitive auditory nerve cells become less effective or die. This results in the decline of a person’s hearing,” said Professor Lesinskas. However, noise is overall, the most significant factor, contributing to hearing loss: “The effect of noise on hearing, depends on the intensity and duration of the noise. This means that a split second of a sound (e.g. an explosion) or industrial noise in factories, etc., without hearing protection throughout the working day, may be equally dangerous.”
Certain leisure activities, such as listening to music using headphones, may damage hearing. This has become known as the ‘teenage pandemic’. “The level of hearing damage depends on how loud the music is, and for how long. The volume of the sound usually depends on the circumstances – for example, a student travelling to school by trolleybus, where the overall noise level is 80 decibels (dB). This means that they will try to play music loud enough to override the external noise. Listening to music at high volume from half an hour to an hour a day, may be dangerous,” noted the professor.
A decade ago in Lithuania, a survey was carried out aimed at determining how loud pupils usually listen to music. “We measured the sound level acceptable to pupils. It turned out that up to 80% of them listen to music too loudly. It is estimated that the hearing capacity of around 15% of teenagers in the developed Western world, is no longer in line with the norm. So far they do not feel it in any way, but the damage will become apparent with age – they will suffer hearing loss at an younger age than other people in the same age group.”
Each situation should be assessed individually
According to the professor, it is considered that a person listens to music using headphones too loudly if the person next to them can hear it. “To be on the safe side, manufacturers also install sound limiters in the devices. This ensures that an intense sound would not damage hearing. However, listening to music at a maximum volume on such a device longer term, may be harmful to hearing.”
“The sound level of our environment is measured in decibels. The quietest sound we can hear is 0 dB. The intensity of the sound of whispering and the light rustling of leaves in a forest, is 30 dB; normal conversation – 40-50 dB; a baby crying or a dog barking is 80 dB; an operating chain saw produces 90 dB, and the sound in a night club may reach 100-105 dB. It is interesting that the urban background noise, which we often do not even notice, reaches 60 dB,” Professor Lesinskas explained.
During the interview, the professor repeatedly noted that each person must take care of his health and evaluate the risks individually. Parents must be responsible during noisy leisure activities (motorsport, water sports, etc.) with children or adolescents, “Thirty minutes in a noisy environment is safe. This does not mean that a person who has been in a noisy environment for a longer period of time will suffer hearing loss. However, those who are in the risk group, for example, those whose hearing nerve is genetically weaker, may face certain consequences. But you will not know about it until after your hearing is damaged. Every year, 1,000 people suffer hearing impairment because of noise and other causes in Lithuania,” the professor noted.
Can damaged hearing be restored?
Hearing damage is usually defined as sudden or chronic. According to Professor Lesinskas, the consequences of chronic hearing damage are incurable, “There are no ways to restore hearing because degeneration develops due to continuous exposure to the hazardous noise. This means that the hearing cell changes its chemical and physical structure, the membranes, etc. As a result, it can no longer and will no longer function as well as before.”
Meanwhile, sudden hearing loss can be reversed in over 50% of people who seek treatment for it. “It can happen that a person losses hearing in a day. Sometimes the cause is clear, sometimes its origin is unknown. Such patients are hospitalized and if the condition has been for no longer than 2 months (but preferably the person should be hospitalised immediately or within the week), negative consequences can be expected to be reversed. We can help about half of the people who have encountered such a problem, the other half, unfortunately, cannot be helped,” the professor explained.
The professor noted however, that today, hearing may be restored for a person deaf in both ears with the help of cochlear implants. “There are cases when people lose their hearing in both ears for one reason or another. They can no longer perform their favourite job, must learn sign language and how to lipread. Furthermore, it is estimated that 20-30 children are born with hearing disabilities in Lithuania every year, but they are able to live a full life thanks to cochlear implants. The possibility of restoring hearing is a miracle in our profession. The technology came about 30 years ago and with technological advances, has become a standard surgical procedure provided by the national healthcare system in Lithuania (and in the entire EU).”
Prof. E. Lesinskas. Photo: VU MF