TOO LOUD????Our ears evolved over the millennia in the backdrop ofsilence. In ancient times, our life was marked by thesound of wind, of water, temple bells, of the cries ofwild animals and, most importantly, laughter.Come 20th Century, all this changed. Industry,automobiles, aircraft, jackhammers arrived. Also,engineering equipment began tearing up the ground tobuild tall buildings and skyscrapers — there was bignoise all around.Today, we are marooned with a medley of noise that ourears were never designed for.Honking, music systems, personal stereos, and iPods…the list is endless. They have only added to blazingcacophony.Too much noise is damaging to us. The irony is — wedon't notice until it's too late to do anything aboutit.
ORIGIN OF SOUND AS LANGAUGE OS SPEECH: the infant hears his first sounds outside the womb, the moment it is born. A normal hearing infant is exposed to all kinds of sounds, i.e. Speech-language of his environment, sounds of toys, birds chirping…. The list is endless. This according to the Chomskian theory of Language development helps him to develop adequate speech and Language skills.
Following are the typical milestones regarding the child’s’ speech and hearing development:
Birth – 2 months → startling response to loud sounds
2months – 6months → eye movements to sounds
6months – 12 months → head turning response to sounds, human voice
> 12 months → child babbles mama…baba… etc.
1½ years → single meaningful words
2½ years → 2- word phrases (“mama give”; “give ball”)
3 years and above → meaningful simple sentences (“mama give ball”)
It is known and seen that any disruption in the sensory status of the Ear (any degree or type of deafness) causes marked speech-language delay.
POWER VIS-A-VIS SOUND:
Sound may be described in terms of physical as well as psychological phenomena. I.e. a series of disturbances of molecules within an elastic medium and an auditory experience- hearing something, respectively.
Sound is generated by vibration and is carried through the air around us in form of pressure waves. Only when these waves strike the ear that hearing takes place.
Human reactions to sound are psychological and reflect such subjective experiences as pitch, loudness, sound quality and ability to tell the direction of the sound source. The range of human ear is very great and so the unit called “ decibel (dB)” is used for intensity.
Airborne sounds are measured by devices called Sound Level Meters as concern over noise pollution grows SLMs are useful in the study of acoustics in industry and environment.
All sounds that normal hearing persons may hear without discomfort can be found in the range form: threshold of audibility to threshold of discomfort.
The approximations can be determined with the help of the following table
0dB: just audible sound
10dB: soft rustle of leaves
20dB: whisper at 4ft
30dB: gurgling of a stream
40dB: night noises in the city (threshold or outskirts of city)
50dB: quiet automobile 10ft away
60-70dB: normal conversation at 3ft
80dB: heavy traffic/ loud telephone rings
90dB: pneumatic drill 10ft away
100-110dB: oil tanker explosion few ft away
120dB: A blaring stereo close by (1ft)./ aeroplane flying (near airports)
Noise Induced hearing loss (NIHL)
The industrial Revolution’s introduction of high noise levels brought a greater threat to the human auditory system than evolution had prepared for. In some cases hearing losses may result from brief exposure to high-level sounds, with subsequent partial or complete recovery (temporary hearing threshold shift). In other cases repeated exposure to high-level sounds result in permanent hearing impairment (permanent hearing threshold shift). According to studies hearing loss may be due to biological changes in the sensory cells (of the inner ear), physical dislodging of hair cells during hyper acoustic stimulation, changes in the cochlear blood supply, loss of outer hair cells, rupture of Reissner’s membrane, or detachment of the organ of corti from the basilar membrane.
Acoustic trauma indicates NIHL from impulsive sounds such as explosions.
Exposure to jet engines, drop forges, pneumatic hammers, subways, rock music, and even computers has been documented to be causing hearing loss.
Hearing conservation program (HCP):
1 identifies people who are at risk for NIHL
2 abates dangerous noise levels as economically as possible
3 protects employees who are at-risk for NIHL. (use of protective hearing devices such as ear muffs or ear plugs)
4 periodic hearing examinations a must.
5 setting regulations for the society (deadlines for loudspeakers)
importance of the awareness: many persons effected usally are unaware of the hearing losses caused due to noise exposure. By the time they do, severe communicative difficulties also set in, thus effecting the person overall.
Bottom line: Take care of your ears before it is too late. Hearing aids of even the best technological advantage cannot replicate the human ear.
PREVENTION IS ALWAYS BETTER THAN CURE.
ORIGIN OF SOUND AS LANGAUGE OS SPEECH: the infant hears his first sounds outside the womb, the moment it is born. A normal hearing infant is exposed to all kinds of sounds, i.e. Speech-language of his environment, sounds of toys, birds chirping…. The list is endless. This according to the Chomskian theory of Language development helps him to develop adequate speech and Language skills.
Following are the typical milestones regarding the child’s’ speech and hearing development:
Birth – 2 months → startling response to loud sounds
2months – 6months → eye movements to sounds
6months – 12 months → head turning response to sounds, human voice
> 12 months → child babbles mama…baba… etc.
1½ years → single meaningful words
2½ years → 2- word phrases (“mama give”; “give ball”)
3 years and above → meaningful simple sentences (“mama give ball”)
It is known and seen that any disruption in the sensory status of the Ear (any degree or type of deafness) causes marked speech-language delay.
POWER VIS-A-VIS SOUND:
Sound may be described in terms of physical as well as psychological phenomena. I.e. a series of disturbances of molecules within an elastic medium and an auditory experience- hearing something, respectively.
Sound is generated by vibration and is carried through the air around us in form of pressure waves. Only when these waves strike the ear that hearing takes place.
Human reactions to sound are psychological and reflect such subjective experiences as pitch, loudness, sound quality and ability to tell the direction of the sound source. The range of human ear is very great and so the unit called “ decibel (dB)” is used for intensity.
Airborne sounds are measured by devices called Sound Level Meters as concern over noise pollution grows SLMs are useful in the study of acoustics in industry and environment.
All sounds that normal hearing persons may hear without discomfort can be found in the range form: threshold of audibility to threshold of discomfort.
The approximations can be determined with the help of the following table
0dB: just audible sound
10dB: soft rustle of leaves
20dB: whisper at 4ft
30dB: gurgling of a stream
40dB: night noises in the city (threshold or outskirts of city)
50dB: quiet automobile 10ft away
60-70dB: normal conversation at 3ft
80dB: heavy traffic/ loud telephone rings
90dB: pneumatic drill 10ft away
100-110dB: oil tanker explosion few ft away
120dB: A blaring stereo close by (1ft)./ aeroplane flying (near airports)
Noise Induced hearing loss (NIHL)
The industrial Revolution’s introduction of high noise levels brought a greater threat to the human auditory system than evolution had prepared for. In some cases hearing losses may result from brief exposure to high-level sounds, with subsequent partial or complete recovery (temporary hearing threshold shift). In other cases repeated exposure to high-level sounds result in permanent hearing impairment (permanent hearing threshold shift). According to studies hearing loss may be due to biological changes in the sensory cells (of the inner ear), physical dislodging of hair cells during hyper acoustic stimulation, changes in the cochlear blood supply, loss of outer hair cells, rupture of Reissner’s membrane, or detachment of the organ of corti from the basilar membrane.
Acoustic trauma indicates NIHL from impulsive sounds such as explosions.
Exposure to jet engines, drop forges, pneumatic hammers, subways, rock music, and even computers has been documented to be causing hearing loss.
Hearing conservation program (HCP):
1 identifies people who are at risk for NIHL
2 abates dangerous noise levels as economically as possible
3 protects employees who are at-risk for NIHL. (use of protective hearing devices such as ear muffs or ear plugs)
4 periodic hearing examinations a must.
5 setting regulations for the society (deadlines for loudspeakers)
importance of the awareness: many persons effected usally are unaware of the hearing losses caused due to noise exposure. By the time they do, severe communicative difficulties also set in, thus effecting the person overall.
Bottom line: Take care of your ears before it is too late. Hearing aids of even the best technological advantage cannot replicate the human ear.
PREVENTION IS ALWAYS BETTER THAN CURE.
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| hearing conservation program |
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