Improving the efficiency of the digit triplet test using digit scoring with variable adaptive step sizes

Abstract

Objective: To investigate modifications of the Flemish Digit Triplet Test (DTT) to improve its efficiency, i.e. the use of a low-pass filtered noise and variable adaptive step sizes according to a digit scoring procedure, targeting different recognition probabilities.

Design and study sample: Speech reception thresholds (SRT) were evaluated in terms of their test-retest reliability and correlation with pure tone averages (PTA) in a group of 68 adult participants with different degrees of hearing impairment.

Results: The use of a low-pass filtered noise did not result in better test-retest reliability or an improved SRT-PTA correlation. Using digit scoring with adaptive step sizes parametrised to target a recognition probability of 79% (D79), corresponding to the recognition probability of the currently used DTT with triplet scoring and fixed adaptive step sizes of 2 dB, increased test-retest reliability. Lower recognition probabilities of 57 and 35% demonstrated worse reliability and worse SRT-PTA correlations.

Conclusions: Given the increased test-retest reliability of D79, a similar reliability as for the currently used DTT could be obtained after considerably fewer trials, leading to a profit in test duration.

Keywords:

• Digit triplet test
• efficiency
• hearing screening

Acknowledgements

The authors thank Erica Schoonjans, Babette Van De Velde and Lien Zwysen (master students of the Speech-Language Pathology and Audiology programme, KU Leuven) for their help with participant recruitment and data collection. Heleen Luts is acknowledged for her methodological support.

Portions of this article were presented at the European Federation of Audiology (EFAS) conference (Istanbul, Turkey, May 27–30, 2015).

Disclosure statement

The authors report no conflicts of interest.

Additional information

Funding

This work was supported by a TBM-FWO grant from the Research Foundation Flanders (grant number T002216N) and by KU Leuven project OT/12/98.