Occupational Hearing Loss “Preventable Condition”

Press, Volume CI, Issue 29901, 15 August 1962, Page 6

Occupational Hearing Loss “Preventable Condition”

Occupational hearing loss was still largely unrecognised by employers and employees, Dr. J. Coppiestone, of the University of Otago, told the symposium on noise and noise control al the science congress yesterday. “Basic research shows that hearing loss due to exposure to loud noise to an eminently preventable Condition and it is now our task to prevent it in New Zealand,” he said. Twenty per «nt. of workers were exposed to this hazard, he said. “The fundamental cause of occupational hearing loss is the total sound energy received in the inner ear during a work day and during a lifetime, and the dSsbribution of that energy as a function of frequency,” Dr. Coppiestone said. “If energy levels are excessive, permanent damage is caused to the dedicate hair cells of the cochleau resulting in a loss of their sensitivity to any sound at their specific frequency.” First affected were ceils receiving at 4000 cycles a second. Because this frequency was outside the range of normal speech, the onset of this condition was at first unrecognised by man. Hearing acuity fell off with age, but W was also demonstrated thtt the loss due to age was superimposed upon loss due to noise. “It Is essential that early noise damage be discovered as soon as possible in the young worker, and the necessary steps taken to prevent it worsening,” he said. “If he continues to work without protection in an environment of excessive noise, the damage will extend and to it

will be added the loss due to age. “The result will be that in his latter years he will be hard of hearing to a greater or lesser degree and this is a considerable handicap to his enjoyment of life, . 'There is good evidence that the rate of damage due to noise is at a maximum during the first 10. years of exposure, underlining the importance of early ascertainment,” Dr. Coppiestone said.

“Unfortunately, the insidious onset and long course of

this condition -militate* against its ready recognition by the public, but the seriousness lies in its permanency once established. “Hazardous, sound levels are in general only encountered in the course of occupation, but this does not necessarily infer in industry. It has been shown that tractor drivers not infrequently suffer some hearing loss and wherever machinery is used, in town or country, there is a potential hazard. “We badly need mote surveys of the noise environment so that comprehensive and realistic hearing conservation programmes can be introduced and we also need a great deal of both professional and public education in the nature and implications of thia very real problem,” Dr. Coppiestone said.