The digit triplets test is based on a procedure which makes it possible to determine how well acoustic signals are perceived despite background noise interference. During the test, spoken combinations of three digits are heard with background noise superimposed over them. Subjects must enter the combinations they hear in a field using a numeric keypad on the screen or the computer keyboard. Depending on the answers, randomly generated digits will be repeated, so that the test will last 1 to 3 minutes.
The test ends with an assessment of the level of understanding of the spoken words compared with that expected in a person with normal hearing.
The issue in medical terms is whether the digits entered genuinely reflect the hearing ability of the user, i.e. whether the entries, and therefore the results of assessment of hearing ability by means of the digit triplets test, are valid.
With this in view, the digit triplets test was validated in a study involving groups of 10 normal-hearing and 20 hearing-impaired subjects.
During the online hearing test, the sounds are played in both ears at the same time, meaning that only the subject’s better ear is tested during audiometry. The reason for employment of this binaural stimulus method is so that users can use free-field speakers for the test. For screening purposes, it is acceptable to test the better ear, as the test still assesses potential problems in communication situations where hearing impairment is likely to have the most impact. The results of the study showed that the digit triplets test can be used for a screening test of hearing, but does not represent a replacement for a diagnostic test. Nevertheless, it is a widely accessible, scientifically proven (“evidence-based”) and user-friendly online screening method (Buschermöhle et. al., 2015).
Buschermöhle, M., et al., The German Digit Triplets Test (Part II): Validation and Pass/Fail Criteria. Z Audiol, 2015. 54 (1): p. 6 – 13.
