VDB-Express Test

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

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 
   calculation.
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