Speech-in-noise test (digit triplets test)

The digit triplets test can be used for swift screening of communication abilities. It produces threshold estimates in just a few minutes. The digit triplets test is a speech-recognition-in-noise test using spoken combinations of three digits, presented in a noise background. In four of the six available languages, the digits are preceded by an introductory phrase for catching the listener’s attention (all except Dutch and Polish test). By adaptively varying the signal-to-noise ratio (SNR), the SRT (speech reception threshold: SNR for 50 percent correct triplets) is obtained as a measure of speech recognition abilities under adverse conditions. Because of the simple instructions, the digit-triplet tests are very suitable for automatic and self-screening operation. Combined with the short measurement time, this makes the test particularly suitable as a screening test.

Depending on the SRT measured in the test, one of the following result categories is presented to the user:

  • “Your performance in this hearing test was well below average.” (worst possible result)
  • “Your performance in this hearing test was below average.” (intermediate result)
  • “Your performance in this hearing test was within the normal range.” (best possible result)

Irrespective of the result, the following additional advice is given to the user: “Although this test does not cover all aspects of hearing and is no substitute for a medical diagnosis, you may wish to visit your GP in order to receive a more detailed assessment of your hearing.”

In addition to public screening via the internet and the telephone, the digit triplets test can be used for a quick assessment of speech intelligibility in clinics, research centres or the hearing industry.

Examples:

  •   Die Ziffern … fünf … acht ... eins.
  •   The digits ... five ... three ... one.
  •   Nu hör du … fem … noll … fem.
  •   Les numéros ... quatre ... trois ... un.
  •   ... drie ... één ... twee.
  •   … trzy … jeden … dwa.

Internet versions: Dutch, German, English, Polish, Swedish

This test was originally developed at the VU University Medical Centre in Amsterdam, the Netherlands, as a hearing test by telephone. Telephone versions of the digit triplets test are available in the United Kingdom, in the Netherlands, and in Germany. A telephone version will soon be available in Poland, Sweden and France.

Literature:
Smits, C., Kapteyn, T.S., and Houtgast, T. (2004) Development and validation of an automatic speech-in-noise screening test by telephone. Int. J. Audiol. 43, pp. 15-28.
Smits, C., Houtgast, T. (2005) Results from the Dutch speech-in-noise screening test by telephone. Ear Hear. 26, pp. 89-95.

Partner institutions:

HörTech gGmbH, Oldenburg HörTech gGmbH, Oldenburg Institute of Sound and Vibration Research, Southampton Institute of Sound and Vibration Research, Southampton
Adam Mickiewicz University Poznan Adam Mickiewicz University Poznan Division of Technical Audiology, Linköping University Division of Technical Audiology, Linköping University
 Katholieke Universiteit Leuven Katholieke Universiteit Leuven  VU Amsterdam Medical Centre Vrije Universiteit Amsterdam Medisch Centrum