VDB-Express Test

15 February 2022
10 - 30 mins

What is the VDB-Express test?

Difficulty with hearing in background noise is a common complaint among hearing aid users. Therefore, the measurement of SNR loss (signal-to-noise ratio loss) is important because a person’s ability to understand speech in noise cannot be reliably predicted from the pure tone audiogram. The VDB-Express test was developed to provide a quick estimate of SNR loss for French listeners. A list of nine sentences with three key words per sentence is presented in speech babble noise. The sentences are presented at pre-recorded signal-to-noise ratios (SNR) which decrease in 3-dB steps from -18 dB (very easy) to 3 dB (extremely difficult). The SNRs used are: -18, -15, -12, -9, -6, -3, 0 and 3 dB, encompassing normal to severely impaired performance in noise.


Required equipment

  • The Callisto™ hardware
  • Licensed AC440 Audiometry module within your Callisto™ hardware
  • VDB-Express License in your Callisto™ hardware
  • Calibrated Headphones, insert phones or Free-Field Speaker


Test procedure

VDB Express test screen, showing a mild SNR loss of 4.5 dB.

  1. Open the AC440 and enter the VDB-Express screen by selecting Menu | Tests | VDB-Express. 

  2. Select the output level. The channels are synchronised for this material to ensure that the correct SNR level is achieved.
  3. Select a list in the corresponding dropdown. e.g. “Liste 2”.
  4. Instruct the patient to repeat the sentences and try to ignore the noise that they will also hear 
    through the headphones.
  5. Press START to begin the test.
  6. The first sentence is always a practice sentence and its score will not contribute to the final result 
  7. The number of words in bold the patient repeats correctly should be scored by clicking on the score 
    buttons. Scoring is disabled until the sentence has been played completely.
  8. When 9 sentences are scored a total score will be calculated. 
    Note that if you press Stop before the 9 sentences of the list have been played and scored, no total 
    score will be calculated.
  9. The total score can be compared to the “SNR loss definitions”.
  10. Save the VDB-Express test by clicking Save


How to activate aided VDB-Express

  1. Ensure you are in the VDB-Express screen.
  2. Select Free Field as the Transducer; this will activate the “Aided” function.
  3. Click on the Aided button; this will add an extra column on to the VDB-Express scoring table


Comparing Aided and Unaided VDB-Express scores over time

Clinicians are now able to compare the Unaided and Aided SNR scores. 
To view the scores in a graph view, click on the graph icon Graph icon, with white arrows pointing in the rightward and downward positions, and a blue and a red dot in the middle.

Three results can be seen. For the same wordlist, the unaided SNR score indicates a mild SNR loss, while the aided SNR loss is 1.5 dB, which is normal.



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