Hearing damage and loss due to earphone use

The volume and duration of exposure are both important when it comes to the effects of noise on health. According to the US Centers for Disease Control and Prevention (CDC), listening to loud noises for a long time can cause hearing loss just as much as a one-time exposure to extremely loud noise.

What essentially happens in the longer run is not just damage to the cells and membranes in the cochlea or inner ear, but also the overworking of the hair cells in the ear which can lead to these cells dying. In fact, 30-50% of these hair cells may already be damaged by the time an auditory test detects a problem.

The longer the exposure, the greater the harm—but that’s not where this ends because the damage can be permanent in the auditory neural system and the effects of the exposure are likely to last even after the exposure has stopped.

According to the UK’s National Health Service, any noise above 85dB (decibels) is considered to be harmful, especially if the exposure to it is for longer durations. A sound is considered to be loud if: 

• It hurts your ears
• You can’t hear what people near you are saying
• You have to raise your voice to talk to people near you
• You feel a ringing in your ears even after the noise has subsided, i.e., tinnitus
• You experience muffled hearing after the noise has subsided

The following are some common types of noises and their decibels to give you an idea of why keeping the sound levels below 85dB is good for you:

• Whispering (30dB) is not harmful
• Conversation (60dB) is not harmful 
• Busy traffic (70-85dB) is harmful
• Motorbike (90dB) is very harmful
• Listening to music on full volume through a PLD (100-110dB) is extremely harmful
• Plane taking off (120dB) is extremely harmful

Sound levels above 85dB are harmful. And some studies have revealed that exposure to noise at 85dB for eight hours is likely to lead to hearing loss.

As a direct source of noise into the ears, earphones or headphones can be harmful to auditory health, especially when they are used over a longer period. Even the most ordinary earphones available today emit an average of 85-100dB of maximum sound. Some of these PLDs (personal listening device) are also kitted out with “noise cancellation” tech, which basically encloses your ears and makes it impossible to hear any surrounding sounds.

Otology experts and ENT specialists agree that if you are unable to hear any other sounds while your earphones are on, it’s likely you are already doing irreparable damage to the nerves and cells of your ears. The development of hearing loss due to earphone use is more likely to be gradual and cumulative, which is why understanding the warning signs is important. The following are the signs of hearing damage that you should take note of—visit an ENT specialist as soon as possible if you notice any of these:

• Feeling that your ears are ringing, buzzing or hissing without any direct source of noise, also known as tinnitus
• Difficulty understanding speech at normal sound levels in noisy places
• Hearing muffled sounds
• Feeling that your ears are plugged
• Listening to the television or music at a louder sound level than before

The inner ear contains a snail-shaped structure called cochlea which is filled with fluid. Sound vibrations create waves in the cochlear fluid and the hair cells (which act as receptors), and this transforms the sound vibrations into electrical signals which are then sent to the brain. Any damage to the cochlear fluid and the hair cells can cause hearing loss, and prolonged use of earphones at higher volumes is one of the leading culprits. 

A study published in the journal Noise and Health in 2017 revealed that those who used earphones at 90-100dB thresholds regularly and for prolonged periods of time had the greatest risks of developing hearing impairments due to cochlear damage and tinnitus. Subjects who listened to moderate sound levels for shorter durations were likely to be at a lower risk of hearing damage and eventual hearing loss.

You might assume that since earphones are basically in-ear devices, they would not cause as much long-term damage to the outer ear. But the outer and middle ear funnel the sound waves into the ear canal all the way to the cochlea and the auditory nerve. This means that loud and prolonged noises can affect the hair cells and bones of the outer ear as well. There is, however, an additional way in which earphone use can lead to hearing damage and loss.

When you put the earphones on, it creates an enclosed environment within the ear canal. With prolonged use, the temperature and humidity in the ear canal increases, creating the perfect environment for the growth of bacteria, fungi and all types of microbes that cause infections. If and when earphones with hard earbuds cause scratches, cuts or abrasions inside the ear, it allows the microbes to cause an outer ear infection. A study published in the Malaysian Journal of Medical Sciences in 2002 underlines this risk of outer ear infections, and mentions that chronic outer ear infections can also lead to eventual hearing loss.

The risk of outer and inner ear damage due to prolonged earphone use is therefore quite high. That said, earphone use is not just associated with leisure activities any more. Given our dependence on laptops and personal computers for work and meetings in almost all fields, it’s associated with our professional lives as well. So, while completely stopping the use of earphones is not in your hands, you can use the following ear and earphone care tips to reduce the damage to your ears and the potential risk of hearing loss.