by Eric Fairman
Standing outside enjoying the pure, night air also gives one the opportunity to ‘hear’ the silence of the night. Such silence is truly ‘golden’ and comes as a refreshing antidote to the noises of the daylight hours. Not that the noises that I am subjected to are anything to lament about, on the contrary, most are ‘natural’ sounds made by bird, beast, wind or rain, with the occasional hum of the tractor in nearby orchards or paddocks, none of which generally exceed a noise level much higher than 45 decibels (dB) in my immediate environment.
Decibels (dB) is the unit used to measure the intensity of sound The hum of conversation is rated at 60 dB in a lively office or school environment. In the home, noise levels vary between 65 dB for the washing machine or dishwasher, through to 80 dB for an alarm clock, to 85 dB for an electric shaver! Walking through the city can expose us to sound in the range of 80 - 90 dB at the minimum.
The results of research, in the form of ‘hearing tests’, conducted at a university in the USA amongst a group of middle and high school students, revealed that 17% of those tested had varying degrees of hearing loss. The test results further revealed that the greatest hearing loss was in the higher ranges of pitch. Such a discovery was not in itself surprising, for initial damage to hearing usually effects the reception of high frequency sounds after exposure to excessive noise.
How does this relate to everyday life. An early indicator of partial hearing loss may be a difficulty or an inability to hear high-pitched voices. Further manifestations of partial hearing loss may be revealed in difficulties with distinguishing particular consonant blends, such as S, F or a soft C, CH, SH and H. The result is that words such as ‘sill’, ‘fill’, ‘sill’, ‘hill’, ‘hell’, ‘shell’, etc., sound almost identical!
Unfortunately, such a phenomenon is not restricted to middle or high school students, for it is becoming increasingly common for young children to be diagnosed with hearing loss, even before they commence school!! It is but a short step to make a logical connection between hearing loss and the prevalence of specific learning challenges experienced by an increasing number of children.
Noise induced hearing loss (NIHL) can occur at any age and we can experience temporary loss after as little as fifteen minutes exposure to loud sounds. Symptoms can include a diminished ability to hear sounds which one is normally able to hear. In addition there may be a ‘ringing’ in the ears (tinnitus) or the ears may have the feeling of being ‘blocked’. Hearing loss may be caused by any loud sound which continues for an extended period of time. Fortunately, our hearing will generally return after awhile, but never quite to the level of what it was previously, although we may not be able to detect any change in our ability to hear after short exposure on an irregular basis. Unfortunately, hearing loss is generally only detected after a hearing test
In children and adolescents, the greatest damage to hearing is caused by listening to continuous loud ‘pounding’ music. If the music is so loud that one has to raise one’s voice to be heard in a conversation, then rest assured that your hearing is being damaged. Attendance at discos, night clubs or other such events are an obvious source of such excessive noise.
Another source of excessive sound is through the prolific use of headphones to listen to music played on the ‘diskman’, ‘walkman’ or iPod. Young people will spend hours on end listening to music via headphones. Most of the time at a level well in excess of what could be deemed appropriate. How often do we sit or stand next to a fellow passenger in a ‘bus or train who is wearing headphones from which we are able, despite the noise of the vehicle’s engine, to hear the emanating sound? If anyone other than the user of the apparatus is able to hear the sound, then the volume is too loud and damage is being done to the user’s hearing. If the listener maintains the same volume for extended periods of time, then the hearing will suffer irreparable damage.
Let us consider for a moment the structure of the ear in an attempt to understand how hearing loss occurs (this is generally taught to students as part of their Physiology lessons in Year Seven in Steiner-Waldorf schools). We can look upon the ear as a complex organ comprised of three main parts: the outer ear, the middle ear and the inner ear. The outer and middle ear, are separated by a thin membrane called the ‘eardrum’. Sound hits this membrane and causes it to vibrate and these vibrations travel to the middle ear and are conveyed to three minute bones, namely the: malleus, incus and stapes (more commonly known as the hammer, anvil and stirrup). The vibrations are then transmitted to the inner ear to be picked up by tiny sensory 'hair cells' in the cochlea that transforms the vibrations into nerve impulses, which in turn are transmitted to the brain via the auditory nerve
These 'hair cells' are exceedingly delicate microscopic structures, arranged in ‘V’ shaped groups, that easily become damaged when bombarded by loud noise. Damage results in the ‘hairs’ becoming entangled and loosing the ability to remain upright. If this damage is the result of brief exposure to loud noise, then there is every chance that they will recover to some degree, but never totally. However, when the damage is the result of impulse noise, such as an explosion, damage may be irreversible. Irreversible damage may also occur when the hairs’ are subjected to loud noise on a regular basis. The ‘hairs’ never really have time to recover between one listening session and another, and eventually they become too weak and die, resulting in progressive hearing loss.
Our hearing is also susceptible to damage when we ‘work-out’ at the gym!! To while-away the time spent on apparatus, we may wear headphones to listen to music. However, although exercise can be beneficial for our physique, intense exercise also brings us to a state of stress, at which time our ears become far more sensitive to sound. At this stage, noise doesn’t even have to be loud to cause mild damage! Thus, the use of headphones whilst exercising is to be avoided.
‘Workplace Health and Safety Regulations’ in most western societies, require that ear protection be worn when there is a likelihood of noise levels reaching or exceeding 85 dB. Amplified music easily reaches 110 - 130 dB, which equals the noise of a jet aircraft flying overhead, but no ear protection is worn!! Many young people play their diskman/walkman at 110 dB or more for hours at a time. Much of the loud modern music which they currently listen to, has the regular ‘thud-thud-thud’ of the bass drum. These low notes have the ability to flatten hairs cells in much the same way as mature trees can be flattened in a fierce wind storm.
As educators, we have a responsibility not only to teach young people about the wonders of the world, but we also have a responsibility to instill in them a respect for their bodies and at the same time, make efforts to protect them from those things which may harm them in one way or another. The foregoing goes some way towards explaining why educators have strong reservations and concerns with regards to the use of a ‘diskman’ or ‘walkman’ by students of any age.
This concern also extends to other forms of electronic amplification of sound, especially the amplification often experienced in cinemas. Sound which is too loud contravenes most ‘Health and Safety Regulations’ and we have a duty of care, both to ourselves and our children, to bring such contraventions to the attention of the management for their timely and appropriate action.
There are of course many other sources of noise other than that caused by electronic amplification. We are subjected to noise wherever we are, be it at home, at work or enjoying recreational activities. In the home we have the TV; food mixer; vacuum cleaner; workshop tools; lawn mowers and leaf blowers. On the way to work or in the workplace we are subjected to a cacophony of sounds emanating from motor vehicles of all shapes and sizes; pneumatic drills; sirens; machinery, etc. Recreational life may take us to formula one, motor cycle or go-kart race tracks; speed boats; rifle ranges or hunting. Regardless of our environment, we can all be subjected to one form or another of excessive noise.
Noise induced hearing loss (NIHL) is preventable. Firstly, we should educate ourselves about the hazards of noise, and become alert to the presence of hazardous noise in our environment, so that we are in a better position to care for the hearing health of the young.
Secondly, the use of effective ear plugs or other forms of hearing protection, should become an acceptable part of everyday life. Appropriate forms of protection are easily obtainable from chemists, drugstores, good sporting and hardware stores. When there is suspicion of hearing loss, however slight then it is advisable to undergo an examination and hearing test conducted by an audiologist.
‘SILENCE IS GOLDEN’
– but only if we are blessed with the ability to hear –
Eric Fairman taught for many years in Waldorf schools in Britain and Australia. He is the author of the Path of Discovery series.