Noise Exposure and Hearing Conservation Lecture Powerpoint

Question 1

Higher frequencies are heard where in the cochlea? Lower ones? Why does sensorineural hearing loss impact higher frequencies first?**

Answer 1

Right at the entrance to the oval window, deeper in the folds, they are exposed directly at the entrance to the oval window and are thus less protected resulting in their loss sooner than lower pitched sounds***

Question 2

3 types of hearing loss

Answer 2

• Conductive (cerumen, ottitis media, cholesteatoma)
• sensorineural (permanent, noise induced, acoustic neuromas, presbycusis)
• Mixed type

Question 3

Hazardous noise definition

Answer 3

Any auditory stimuli intense enough to cause hearing loss in the human hearing mechanism

Question 4

Temporary threshold shift

Answer 4

Temporary decrease in hearing sensitivity (muffled or tinnitus) after exposure to a loud noise that if repeated can result in permanent loss

Question 5

Decibel threshold that OSHA requires ear protection (3)***

Answer 5

> =85 dB averaged over an 8 hour shift requires enrollment in hearing conservation program but have choice of wearing earplugs
=90dB averaged over 8 hour shift is max allowed, hearing protection required, earplugs must be used
-Noise above 140dB is not permitted

Question 6

Elements of a hearing conservation program (6)

Answer 6

• noise measurement (in ear dosimeter is best option)
• engineering and administrative controls (safety glass and such)
• monitoring audiometry (14 hours without exposure to workplace and nonoccupational noise must precede baseline audiogram testing, then must return annually unless standard threshold shift does occur then retest in 30 days)
• hearing protection (all hearing protection has a noise reduction rating of a # of dB and they must drop the exposure below the acceptable dB by OSHA)
• employee training (low compliance in employees)
• record keeping

Question 7

Pure tone booth

Answer 7

A test to determine faintest tones a person can hear at selected frequencies, have individual respond by raising hand or pressing button and these are recorded in an audiogram and then interpreted by a technician

Question 8

If an average change > or = __dB from baseline while adjusting for presbycusis occurs, then this is considered a standard threshold shift

Answer 8

10

Question 9

What mandates a hearing exposure loss being reportable to OSHA (4)*****

Answer 9

• Is the employee in hearing conservation program
• is current avg loss of >=25dB
• is there a STS of >=10dB
• heaering loss not caused by other medical problems or non-occupational exposure