testing

- The Basic Guide for Testing Children -

Find a quiet site that is free from audio and visual distractions. Prior to test the following preparation should be made:

1. Plug the audiometer into a 110-volt outlet. If the audiometer is battery powered verify battery condition as per
    audiometer instruction manual.
2. Turn power switch to "on" position.
3. Place the "tone reversing" switch in a position permitting a tone only when the tone presentation switch is
     pressed.
4. If audiometer is equipped with masking , the masking dial must be switched "off".
5. Check the audiometer to see if it is working properly. If not, do not use it until it has been repaired
    a. Audiometers must be calibrated every year. The calibration sticker and date must be checked before using.
    b. All levers and controls should operate smoothly and be free of extraneous noises.
    c. While wearing the earphones, the tester (or a person known to have normal hearing) should be able to hear
         the tones at screening levels.
    d. When checked, the signal should switch properly from the right earphone to the left earphone.
    e. The earphone cushions must be free of cracks and splits.
    f.   The earphone cords should be free from breaks. To check for breaks in the cords, press the tone switch,
         shake the cord and listen for interruptions in the signal. Do this for each earphone separately.
6. Turn "output selector" switch to the position which will cause the tone to be presented to the right earphone.
7. Turn the frequency dial to 1000 Hz.
8. Turn the intensity dial to 20 dB HL. With a young child the first tone presentation could be made at a louder
      level (e.g., 40 to 50 dB HL) and gradually reduced to 20 dB HL.
      You are now ready to test.
9.   Instruct the child to raise his hand when he hears a soft sound and to put his hand down when he does not
      hear it. If the child does not respond by raising his hand, there are other ways he can let you know the sound
      was heard, e.g drop a block in in bucket, a simple verbal response , or point to the ear when the sound is heard.
10. Place the earphones over the child's ears with the right earphone (red) over the right ear and the left
      earphone (blue) over the left ear.
11. Present the following tones to the right ear:
       1000 Hz.-20 dB
       2000Hz.-20 dB
       4000 Hz.-20 dB
12.   Repeat this presentation with the opposite ear.
13.   Any child who fails the screening (i.e., who does not respond at 20 dB HL to all six of the test tones) shall be
       rescreened immediately after the screener has reinstructed the child and repositioned the earphones.
14. The screening test is now completed.
15.   Record the results. If the child hears all of the tones in the right ear, she passes the screening for the right
       ear. This should be recorded as a "P" (pass) under the column marked "R" (right). If the child does not hear
       all three of the tones for the right ear. This should be recorded as an "F" (fail) under the column marked "R".
       Use the same procedure for the left ear.
16. A second screening must be done in approximately four to six weeks for those who fail the screening. An
      optional threshold test, to determine the lowest intensity level for each frequency at which a person responds
      may be given to those who fail two screenings four to six weeks apart. Appendix H includes a description of the
      procedure for performing the threshold test.

Screening Preschool Children and Special Populations with pure tones

Pure tone hearing screenings can be administered to most children aged 3 and above. It may be more difficult, however, to test younger children and those whoe are mentally or developmentally delayed. With these children, the tester may use any technique which yields consistent responses to the pure tone stimuli. Some examples follow:
    1. Dropping blocks in a box;
    2. Stacking rings on a cone;
    3. Putting a peg in a peg board;
    4. Giving the tester five;
    5. Giving the tester small pieces of paper or game chips;
    6. Pointing to an ear (not necessarily the test ear);
    7. Squeezing the hand or the finger of the tester (effective with children who have limited control of their limbs);
    8. Telling the tester to "STOP" the beep;
    9. Saying "I hear it" or "beep";
   10. Nodding the head;
   11. Hand Clap.

The tester may help the children learn one of the above responses by physically taking them through the movements of the task. After a few repetitions the child may attempt the response without any cues from the tester.
The practice tones can be presented at a 40 dB or 50 dB level. After the task is learned, the tones can be reduced until the testing level of 20 dB is reached.
Younger children do not always respond when the tone is presented. If a child responds consistently when the tone stops, that response can be considered a valid one.

Screening Preschool Children and Special Populations when pure tones results are not reliable

Picture Card or Select Picture Audiometry is an alternative to traditional pure tone screening. The technique incorporates familiar pictures to the preschooler (eg. cowboy, baseball, firetruck, etc.) that are presented at soft, calibrated, screening levels. The child responds by pointing to the target picture. The test ear is considered a pass when three of five pictures are correctly selected.   Although this technique utlizes speech and not pure tones, the results correspond very favorably to the pure tone screening test, ie. the pure tone average of 500, 1000, 2000 Hz.

1. Be sure the meter needle points to "0" on track one, reference signal
2. Be sure the child is familiar with the pictures. (Parents or teachers can help with this.)
3. First word is presented at 50 db to assure the child understands the instructions.
4. The next words are presented at 20 dB screening level, test one ear at a time, and the ear passes screening
     when the majority of of stimuli are identified correctly, eg. 3 out of 5.

Hearing Threshold Test Procedure when the screening test fails in one or booth ears (ASHA 1978)

1. Set the frequency dial to 1000Hz and the intensity control to 30 dB. (In the following steps the tone is
     presented for four seconds.)
2. If the child raises his hand, decrease the intensity of the tone by 10 dB.
3. Continue decreasing the intensity of the tone in 10 dB steps until the child no longer responds.
4. At this point, increase the intensity of the tone in 5 dB steps until the child responds again. Mentally note this
     point by reading the intensity level on the dial.
5. Decrease the intensity of the tone in 10 dB steps until the child no longer responds.
6. Continue increasing and decreasing the intensity of the tone until the threshold has been found. Threshold is
     the lowest intensity level at which the child responds two out of three times.
7. Record the threshold for that frequency on the audiogram.
8. After obtaining the threshold for 1000 Hz., find the thresholds for 2000 Hz., and 4000 Hz. The thresholds are
     obtained first for the right ear and then for the left ear.