Modern mobile electronic devices — smartphones — are small but powerful computers that can continuously receive audio and video data, and the potential harm they can do is increasingly associated with the duration of use of such devices [1–5].

According to WHO, 1.1 billion young people worldwide are at risk of hearing loss because of the exposure to noise in recreational and entertainment settings. Nearly 50% of all adolescents and young adults aged 12 to 35 use their personal audio devices with sound volume hazardously high. About 15% of schoolchildren have hearing impairments [6–8].

However, current scientific literature does not have a sufficient number of publications investigating hearing hazard risk factors the younger generation is exposed to, including those related to the conditions of use of mobile electronic devices with headphones and their design features.

This study aimed to identify the leading hearing loss risk factors for children, adolescents and youth associated with use of mobile electronic devices with headphones

MATERIALS AND METHODS

In the 2017–2021 academic years (September through May), we surveyed 518 students in Moscow and 1000 schoolchildren and students in the towns of Izhevsk and Tchaikovsky. Using a standardized questionnaire we collected data on the conditions in which the respondents use mobile electronic devices with headphones, design features of the headphones used and their hearing health status.

The inclusion criteria were: status of a schoolchild, student, signed and submitted informed consent form, questionnaire correctly completed by the respondent or his/her legal representative, one or more years of using mobile electronic devices. The exclusion criteria were: different age, lack of signed informed consent form, lack of the correctly completed questionnaire, using mobile electronic device for less than a year. The study did not endanger participants; it meets the biomedical ethics requirements and conforms to the provisions of the Declaration of Helsinki (1983).

Statistical processing of the data was enabled by Statistica 13.0 (StatSoft Inc.; USA).

RESULTS

With the help of the questionnaire, we established the pattern of use of mobile electronic devices with headphones habitual for schoolchildren and students, as well as design features of the headphones.

By design, there are basically four types of headphones. Over-ear headphones with good noise isolation, good sound quality at a lower volume level; such headphones deliver sound into the auricle and not the ear canal, which reduces the impact on the eardrum; ear cushions of over-ear headphones completely cover the auricles and fit snugly to the head. Onear headphones fit well to the ear but do not wrap around it completely, do not create increased sound pressure on the acoustic apparatus and have average noise isolation. In-ear headphones (earphones) with silicone tips offer good sound isolation and good sound quality at a lower volume level, but they are put into the external auditory canal, which brings the sound source as close as possible to the inner ear and affects the eardrum. Plastic in-ear headphones (also called “classic earphones”) are put in the auricle in front of the ear canal; they offer poor sound isolation, which translates into higher sound volume levels associated with their use. A design feature of the headphones that should be mentioned is the Active Noise Cancellation (also known as Active Noise Control and Active Noise Reduction) technology, which eliminates unwanted noise by adding a specially generated sound to the audio stream. The drawback of this technology is the increased pressure on the eardrums: together with music and noise, we hear “antinoise”, i. e., inverted ambient noise.

Among the surveyed schoolchildren and students of Izhevsk and Chaikovsky, 88.2% prefer in-ear headphones with silicone tips, 8.9% use plastic in-ear headphones and 2.9% use headphones of other types. In Moscow, 95.7% of students prefer in-ear headphones with silicone tips. Headphones of 72.3% of the surveyed schoolchildren and students of Izhevsk and Tchaikovsky are wired, the remaining part of the participants use wireless headphones. On the contrary, in Moscow 71.4% of students that participated in the study use wireless headphones and the rest use wired. Ninety percent of the respondents have been using headphones for no more than 3 years. As for the noise canceling technology, 15.7% of the headphones had it.

Among the respondents, 14.1% usually listen to audio files in headphones at maximum volume.

Students have the longest experience of using mobile electronic devices with headphones: 10.2±1.5 years, while for schoolchildren this value is 7.4±0.9. It is typical for students to use mobile electronic devices with headphones in moving vehicles, while commuting; this setting adds its own specifics to the use case. Over half of the respondents (53.1%) often listen to music on electronic devices with headphones in places where the noise level is high, such as public transport and public spaces, and 49.2% of the participants underestimate the risk of doing so when in a moving transport, i. e. the risk the respective environment, with its insufficient lighting and loud noises, poses to eyes and hears. The degree of risk associated with high noise levels in transport settings is underestimated by 28.4% of students and schoolchildren. While in a moving public transport, 18% of young people listen to music on electronic devices with headphones at a volume of 8.6 ± 1.4 out of 10. The average time of using mobile electronic devices with headphones in transport settings is 17.2±1.2 minutes. Only 15.7% of respondents agree to refrain from listening to audio files in headphones when the level of ambient noise is high. Tinnitus, buzzing in ears that follows listening to audio files in headphones, is known to 22.9% of respondents.

Overall, 14.0% of the respondents mentioned hearing deterioration over the past year, and specifically among students this figure was 13.8% (table).

Calculation of relative risk showed that the risk of hearing deterioration increases 10.4 times when mobile electronic devices with headphones are used for long periods of time, grows 3.2 times when audio files are played at maximum volume, goes up 7.1 times if listening happens in public transport settings.

There were no hearing deterioration cases registered among those who did not use mobile electronic devices with headphones. Most schoolchildren and students whose hearing was impaired have been using headphones for at least a year, preferred in-ear headphones with silicone tips and used them at maximum volume every day, for more than two hours a day, including while in transport.

DISCUSSION

The study revealed that students and schoolchildren use mobile electronic devices with headphones in 95.0% of cases, which confirms the importance of prevention campaigns among children, adolescents and youth aimed at instilling a proper attitude towards using mobile electronic devices with headphones, with such campaigns, in particular, incorporating the necessary information into curricula [9,10].

Numerous research papers highlight the impact of mobile electronic devices on the body systems of children, adolescents and young people. In particular, such devices affect the organ of sight, neuropsychic systems, musculoskeletal system etc. [11,12,13].

However, the effects arising from the use of mobile electronic devices with headphones have not been investigated sufficiently. Russian research literature offers no evidence-b ased information on the safe level of volume and length of use of headphones, which disallows drawing a complete picture of preventive and protective measures designed to safeguard the hearing organ with the modern technological advancements factored in [6, 14].

The effect of sound is cumulative; adverse changes of the hearing organ accumulate gradually, during exposure to this harmful factor. The development of hearing loss is associated with gradual damage to the ear and its deteriorating adaptive capability: as a result of high sound pressure, the time it takes the hearing organ to recover between headphones use sessions increases. Prolonged exposure to excessive acoustic energy adversely affects hearing and can lead to its partial or significant loss [15].

Hearing disorders translate into gaps in received information and poor speech intelligibility, which, in turn, affect the psycho- emotional state of a person and lead to deterioration of the quality of life. More and more often, mobile electronic devices with headphones are used without restriction, and this trend will push up the number of people suffering from speech intelligibility and deteriorating hearing [16].

CONCLUSIONS

Today, schoolchildren and students are exposed to the hearing impairment risks associated with use of mobile electronic devices with headphones, which makes the search for the most efficient ways of forming healthy lifestyle habits among them even more urgent.