Ch. 6: Audiometric Testing Program & Equipment Flashcards
What is an audiometer?
An audiometer is an electrico-acoustical instrument that transmits pure tones through earphones at discrete frequencies (i.e., at separate frequencies of 500, 1000, 2000, 3000 Hz, and so forth) and at known sound pressure levels (e.g., 0 to 100 decibels).
What are three types of audiometers?
The three types of audiometers are the manual audiometer, the microprocessor audiometer, and computer-controlled audiometer.
Which audiometer(s) reduces technician bias?
Technician bias is reduced with the use of a microprocessor audiometer and computer-controlled audiometers (provided the microprocessor audiometer and computer-controlled audiometers are used in the automatic and not the manual mode).
Why is it necessary for audiometric technicians to know the manual technique for testing audiometry even if they have a microprocessor audiometer or computer- controlled audiometer?
- Because the automatic mode cannot be depended upon for establishing all thresholds.
- An example could be an individual with significant tinnitus that interferes with the frequencies tested.
Why should a daily calibration be done?
- To ensure the validity of audiometric testing.
- A form to record your checks should be used.
What is a bioacoustic simulator used for?
- A bioacoustic simulator is used to do a biological check.
- A bio-acoustic simulator is an electronic instrument that responds with either an electric signal or an illuminated light when the audiometer signal output reaches the simulator’s threshold for each frequency.
How often should laboratory, or exhaustive, calibration of the audiometer be done?
Laboratory, or exhaustive, calibration should be done once a year, regardless of how often the audiometer is used. The calibration certificate should be kept with the audiometer for the life of the machine.
What is audiometric zero?
- Audiometric zero is the 0 dB hearing threshold level.
- Zero decibels, in reference to audiometry, is not equivalent to a zero sound pressure level or to the absence of sound.
- It is the average hearing threshold for a defined population of individuals with normal hearing.
- When performing audiometry on a worker, the closer the individual’s thresholds are to 0 dB the closer the person’s hearing is to the normal young ear.
Which lines on the audiogram represent frequencies?
- The vertical lines represent frequencies.
- Frequency levels are noted across the top of the audiogram. The lowest level tested (500 Hz) appears at the far left. Frequencies are progressively higher as one moves to the right.
Which lines on the audiogram represent decibel levels?
- The horizontal lines represent decibel levels; 0 dB (audiometric zero) appears at the upper left corner.
- Decibel levels increase in increments of 10, as one moves down the left-hand side.
What symbol is used on audiograms to represent the left ear?
Blue Xs are used to record thresholds of the left ear.
What symbol is used to represent the right ear?
Red Os are used to record thresholds for the right ear.
How can an audiogram be used?
An audiogram gives a pictorial representation of hearing test results; a worker’s audiometric configuration can be viewed by the technician in this form. The audiogram can be used when counselling and educating workers about their test results and the effects of noise.
Numeric records are another way to document audiometric test results. Cumulative record sheets record all tests for a given worker in sequential order and are useful when determining changes in a worker’s hearing over time.
Why should testing be done in an appropriate testing environment?
Testing in the appropriate environment ensures accurate test results, avoids invalid results, and avoids wasting the technician’s and the worker’s time.
What is an appropriate testing environment?
An appropriate test environment is an environment in which sound levels fall within those prescribed in Schedule 3, Table 3 of the OHS Code.
