Hearing loss and technology

Dr Maxwell Adeyemi

This century has witnessed unprecedented levels of hi-tech technology and devices. Many of them have tremendously enhanced our lives and made life very comfortable. However, some of these gadgets and devices also have the potential to cause untold hardships, pains and even health hazards, if improperly and unwisely utilised.

Have you ever walked into an office to transact business and noticed the increasing number of workers with earphones listening to music via cellphones, mp3, iPods and related devices?

It is also now common place to notice many youths on the street with these tools in total oblivion to their environment in bus stops, shopping malls, even crossing the road, and cannot hear horns or sirens from oncoming vehicles. Some youth also modify their music boxes in their car and play music at horrendous volumes setting up their ear for future deafness.

Maybe it’s your son or daughter that regularly sleeps with these headphones, and wakes up with the music blasting in their ears at amazing decibels!

I believe many of us would have experienced some of these situations. But the greater damage of concern to this habit is the risk of deafness that these youngsters expose themselves to in later years.

Exposing your ear to constant noise at this level eventually leads to chronic deafness, as they are getting used to that level of noise so that you are unable to hear sounds below that level of decibels. Many times, you see people on head/ear phones; you can also hear what they are listening to. Once someone about 2-3 feet away from you can hear what you are listening to, it is not healthy for your ear.

HOW DO WE HEAR?

The ear is made up of three different sections: The outer ear, the middle ear and the inner ear. These parts all work together so you can hear and process sounds.

The outer ear, also called the pinna or auricle, is the part we can see. It’s what we pierce to wear earrings and what we whisper secrets into. It also includes the ear canal, where wax is produced.

The eardrum separates the outer ear from the middle ear and the ossicles – the 3 tiny delicate bones in the ear known as malleus, incus and stapes. It is these bones that pick up sound coming from the outside, via the ear drum, by vibrations and transmit the sound waves into the inner ear. The inner ear receives the vibration from the middle ear. It consists of the cochlea – a small curled tube filled with fluid, which is set into motion, like a wave when the ossicles vibrate.

The cochlea is also lined with tiny cells covered with “hairs” – these hair cells create nerve signals from the sound waves that is then transmitted into the brain and interpreted as sound.

The ear as earlier said is the organ responsible for hearing; the outer ear collects sound waves from an object and directs them to the eardrum which vibrates in response to the waves. These vibrations are converted into electrical neural impulses and transferred to the brain via the auditory nerve for interpretation.

When we detect sound, or noise, our body is changing the energy in sound waves into nerve impulses which the brain interprets. Sound waves are produced when the air is mechanically disturbed.

Sound is measured by:

Frequency: This is the pitch (high or low) of a sound. It is the number of complete sound wave cycles per second. High-frequency noises are more damaging to hearing than low-frequency noises.

Intensity: This is the loudness of a sound. It is measured in decibels.

When we hear a sound, it’s a complex series of event involving:

Sound waves entering the ear canal and causing the ear drum to vibrate.

Vibrations pass through three connected bones in the middle ear.

This motion sets fluid moving in the inner ear.

Moving fluid bends thousands of delicate hair-like cells which convert the vibrations into nerve impulses.

Nerve impulses are carried to the brain by the auditory nerve.

In the brain, these impulses are converted into what we hear as sound.

Exposure to excessive noise or constant noise raises your hearing thresholds – that is, the degree of loudness at which you first begin to hear.

A temporary hearing loss can be caused by exposure to loud noise for a few hours – as many of us get exposed to at Carnival time. Fortunately, hearing is usually restored after a period of time away from the noise.

Permanent hearing loss occurs after the ear has been continually exposed to excessive noise – as with constant plugging of earphones for long hours at work, on the road, or when sleeping, or even using drilling and vibrating equipment etc.

The hair cells that transmit sound waves and vibrations gradually get hardened and die, making it increasingly difficult to recover from the hearing loss. You are unable to hear sounds below the decibels to which the ear has been subjected to; for example, if your earphone operates at 80 decibels on a constant basis, when you sustain noise-induced hearing loss you are unable to hear sounds or conversations below that level, so you have to shout or people have to talk louder for you to hear.

There is no cure for hearing loss caused by noise and hearing aids do not restore noise-damaged hearing. In addition to hearing loss, excessive noise exposure may contribute to mental and physical stress, certain illness and even accidents.

You may be exposed to too much noise if you have trouble understanding normal conversations with someone less than two feet away, you hear prolonged ringing or other unusual noise (tinnitus), or you have trouble hearing TV or speech but can hear normally again after a few hours of leaving the location.

Noise-induced hearing loss – a form of sensori-neural deafness – is typically centred at 4,000 hertz; the louder the noise is, the shorter the safe amount of exposure is. Normally, the safe amount of exposure is reduced by a factor of two for every additional three decibels. For example, the safe daily exposure amount at 85 decibels is eight hours (acceptable standard); while the safe exposure at 91 decibels is only two hours.

Personal audio electronics such as iPods often reaching 115 decibels or higher can produce powerful enough sounds to cause significant noise-induced hearing loss, given that lesser intensities of even 70 decibels can also cause hearing loss.

So before you plug in that iPod, mp3 player, android phone and other musical gadgets into your ears for the whole working hours, whole day or whole night while you sleep, think about the significant damage you will be causing to your hearing over time, which may manifest now or in later years.

Contact Dr Maxwell on 3631807 or 7575411.