Background: In a number of European countries, a functional self-test to screen for hearing impairment
is available via telephone and the Internet. The tests estimate speech-reception thresholds
using an adaptive procedure in which digit triplets are presented at varying signal-to-noise
ratios. In different languages, the stimuli were created either with or without coarticulation;
and some implementations use fresh noise samples, while others do not.
Purpose: The present investigation concerns the influence of coarticulation, prosody, and
noise freshness on measured thresholds.
Study Sample: We performed a laboratory study using 12 normal-hearing listeners.
Research Design: In a blocked design we compared speech-reception thresholds for conditions with and
without fresh noise tokens. In each block we used three types of triplets: with coarticulation
and prosody, with neither, and without coarticulation but with prosody.
Data Collection and Analysis: Thirty-six thresholds were recorded per subject, and they were analyzed using analyses
of variance.
Results: The results showed no significant differences among the three triplet conditions.
The freshness of the noise did not affect thresholds when, at least, a fresh noise
token was used per threshold estimate (23 presentations). Scores dropped significantly
when a whole experimental block was performed with a single noise token.
Key Words
Coarticulation - noise freshness - prosody - speech reception in noise - triple-digit
test
