Posts tagged ‘hearing’

Nowadays Noise Pollution has become rampant in our society, and most of the time we put up with it, partly because we have no idea about what steps can be taken to control it. We tolerate the discomfort others put us through, but it is necessary to be aware of what influence noise has on our bodies, apart from the basic nuisance of having to listen to unwanted noise.

EFFECT ON HEARING: The ability to hear is one of our most precious gifts. Without it, it is very difficult to lead a full life. The damage done by noise depends mainly on how loud it is and on the length of exposure. The frequency or pitch can also have some effect, since high-pitched sounds are more damaging than low-pitched ones. Initially, loud noise tires out the inner ear, leading to temporary hearing loss. However, with continual noise exposure, the ear will lose its ability to recover from temporary hearing loss, and the damage will become permanent. Permanent hearing loss results from the destruction of cells in the inner ear-cells which can never be replaced or repaired. Such damage can be caused by long-term exposure to loud noise or, in some cases, by brief exposures to very loud noises.

EFFECT ON OTHER BODY SYSTEMS: Excessive noise can not only destroy the ability to hear, but may also put stress on other parts of the body. Affecting the heart, noise can cause quickened pulse rate, increased blood pressure and a narrowing of the blood vessels. Over a long period of time, these may place an added burden on the heart. People exposed to noise sometimes complain of nervousness, sleeplessness and fatigue. Excessive noise exposure also can reduce job performance and may cause high rates of absenteeism. People living near airports, railway tracks, busy roads, or other noise-emitting facilities consider sleep disturbance as the most deleterious effect of noise. The data suggest that these noises might affect mood, well-being, and performance the next day. Sleep disturbances are suspected to contribute eventually to the development of chronic health disorders. Most reviewers agree that the effects on sleep depend on the physical characteristics of the noises as well as on individual and situational factors. Noise may also put stress on the body by causing the abnormal secretion of hormones and tensing of muscles. Noise causes the release of different stress hormones. The part of the brain called hypothalamus receives input from, and sends signals to, other parts of the brain, and it produces hormones that stimulate or inhibit the release of other hormones from the anterior pituitary. The pituitary hormones, in turn, stimulate or inhibit the adrenal gland to secrete its hormones, one of the major adrenal hormones being Cortisol. The whole complex interaction of the Hypothalamus, Pituitary and Adrenal Glands is very important and in medical terms, we call it the Hypothalamic-Pituitary-Adrenal Axis of the body. The effects of longer-lasting activation of the HPA-axis, especially long term increase of cortisol, are manifold: immune suppression, insulin resistance (e.g. diabetes), cardiovascular diseases (e.g. hypertension and arteriosclerosis), catabolism (e.g. ostoeporosis), intestinal problems (e.g. stress ulcer) etc. Even worse may be the widespread effects of other hormones outside the hypothalamic system, which have the potential to influence nearly all regulatory systems, causing other medical conditions as signs of disturbed hormonal balance.

EFFECT ON CHILDREN: Compared to earlier years, the lives of children are getting noisier and noisier. Noise levels of the environment, like road traffic, railway sounds, aircraft, etc., have increased considerably. Noise levels at school have also increased dramatically, where more and more use of mikes and amplifiers is being made to reach out to a large number of students. Outdoor leisure activities of children and toys have also become more noisy. Even at home, a large number of households encourage TV sets remaining on for a major part of the day. All this contributes in creating an almost permanently noisy atmosphere for children.
Children possess less well-developed coping responses, and are often less able to control their environments, and as a result effects of noise seem to be more harmful to children in many ways. Aggressive behaviour and hyperactivity seem to be, in part, a consequence of this everlasting noise exposure that children face today.
The information available on noise-induced effects on the fetus shows hearing impairment associated with exposure to high occupational noise levels during pregnancy. On-going research indicates that growth retardation of the child may also be associated with extensive occupational noise exposure of the pregnant mother. It cannot be excluded, but is seems unlikely, that environmental noise causes fetal abnormalities. This may however, be due to lack of proper methods to ascertain this possibility.
Babies who are born pre-term, have to cope with their environment with immature organ systems, especially, the auditory, visual and central nervous systems, which are the last systems to mature. These last stages occur, in part, during the time the pre-term child is in the incubator or neonatal intensive care unit (NICU). Studies need to be conducted to evaluate thoroughly, what effect excessive noise might have on the developing auditory system which would be more vulnerable to hearing impairment.
Where children are concerned, sleep is very important for good health, and studies do show that sleep patterns get disturbed from exposure to noise. As children grow, it has been found that there is a considerable difference in the blood pressures of those exposed to road traffic noise and those not exposed. However, where aircraft noise is concerned, studies show that children adapt to aircraft noise without any major ill effects, this adaptation is not seen in cases of road traffic noise exposure.
Development of reading skills seems to be affected adversely in school children with a long-term exposure to high levels of traffic noise from either aircraft, road or railway traffic. Long term noise-exposed children also seem to suffer from difficulty in concentration and difficulty in focusing their attention, esp. when someone is speaking to them. This perhaps occurs because children learn how to ignore sound stimuli as a way to cope with long-term noise exposure. Unfortunately, this tuning out process may over-generalise so that children learn to tune out not only noise, but also relevant other auditory signals, such as speech.
In families where noise is a part of daily living, parents too seem to be less attentive to their children. This could affect the confidence levels of children as well. Some studies showed that children highly exposed to environmental noise for prolonged periods of time are less motivated when placed in situations where task performance is dependent on persistence. Prolonged exposure to uncontrollable noise seems to induce feelings of helplessness and behavioural patterns which also reflect helplessness. As the child continues to struggle unsuccessfully with an uncontrollable stimulus, it eventually learns that it is helpless to do anything about the situation, as manifested by feelings of hopelessness and reduced persistence. However, personal character traits of a child modify this to a significant extent.
Where teenagers are concerned, studies have concentrated only on the effects of noise causing noise-induced hearing impairment. Listening to music through head phones certainly causes hearing impairment at loud volumes.

According to the National Institute of Occupational Health, continuous exposure to noise levels above 90 decibels can produce adverse auditory and non-auditory health effects. If we want to reduce the chances of these adverse health effects happening to ourselves and to our loved ones, it is essential that every one of us protests whenever someone exposes us to high noise levels and it is our duty, in turn, to see that we do not expose someone else to our noise.