# Development and evaluation of the Digit Triplet Test in Swahili language

## TL;DR

This paper introduces a hearing test in Swahili to accurately assess hearing in Swahili-speaking people.

## Contribution

A new Digit Triplet Test in Swahili was developed and validated for hearing assessments.

## Key findings

- The Swahili Digit Triplet Test achieved a mean SRT of −8.9 dB SNR with a steep psychometric slope.
- Test results were comparable to similar tests in other languages, showing reliability and effectiveness.

## Abstract

The development of a Digit Triplet Test in the Swahili language is an essential step towards providing accurate hearing assessment for Swahili-speaking populations.

This study aimed to develop a Digit Triplet Test in Swahili through a two-part procedure consisting of an optimisation phase and an evaluation phase using normal hearing participants.

A total of 34 subjects participated in the study. During the optimisation phase, a psychometric intelligibility function was determined for each recorded digit, allowing for volume adjustments to standardise the threshold across all digits. This resulted in a lower threshold and a steeper psychometric function for both the triplets and the test lists. Using the optimised speech material, four test lists were created, each containing 27 triplets composed of digits between 1 and 9. The finalised material was then evaluated.

In the final version, the mean Speech Reception Threshold (SRT) for the participants was −8.9 ± 0.6 dB Signal-to-Noise Ratio (SNR), and the mean slope was 24.7 ± 3.5%/dB using triplet scoring.

The psychometric function for normal listeners shows a steep slope with little variation between subjects and across test lists.

The test results are comparable to those of Digit Triplet Tests developed in other languages, indicating the effectiveness and reliability of the Swahili Digit Triplet Test for hearing assessments.