The development and evaluation of the Finnish digit triplet test.
OBJECTIVE
The aim of the study was to develop a reliable and easily accessible screening test for primary detection of hearing impairment.


METHODS
Digits 0-9 were used to form quasirandom digit triplets. First, digit specific intelligibility functions and speech recognition thresholds (SRTs) were determined. To homogenize the test material digits with steep intelligibility function slopes were chosen and level correction up to ±2 dB were applied to the digits as needed. Evaluation measurements were performed to check for systematic differences in intelligibility between the test lists and to obtain normative reference function for normal-hearing listeners.


RESULTS
The mean SRT and the final slope of the test lists were -10.8 ± 0.1 dB signal-to-noise ratio (SNR) and 21.7 ± 1.8%/dB, respectively (measurements at constant level; inter-list variability). The mean SRT and slope of the test subjects were -10.8 ± 0.5 dB SNR and 23.4 ± 5.2%/dB (measurements at constant level; inter-subject variability). The mean SRT for normal-hearing young adults for a single adaptive measurement is -9.8 ± 0.9 dB SNR.


CONCLUSIONS
The Finnish digit triplet test is the first self-screening hearing test in the Finnish language. It was developed according to current standards, and it provides reliable and internationally comparable speech intelligibility measurements.
a Department of Otorhinolaryngology , Kuopio University Hospital , Kuopio , Finland ;|b Institute of Clinical Medicine, University of Eastern Finland , Kuopio , Finland ;
Tytti
T
Willberg
c HörTech gGmbH , Oldenburg , Germany ;|d Cluster of Excellence, 'Hearing4all' , Oldenburg , Germany ;
Michael
M
Buschermöhle
e Department of Otorhinolaryngology , Helsinki University Central Hospital , Helsinki , Finland ;
Ville
V
Sivonen
e Department of Otorhinolaryngology , Helsinki University Central Hospital , Helsinki , Finland ;
Antti A
AA
Aarnisalo
a Department of Otorhinolaryngology , Kuopio University Hospital , Kuopio , Finland ;|b Institute of Clinical Medicine, University of Eastern Finland , Kuopio , Finland ;
Heikki
H
Löppönen
c HörTech gGmbH , Oldenburg , Germany ;|d Cluster of Excellence, 'Hearing4all' , Oldenburg , Germany ;|f Department for Medical Physics and Acoustics , Carl Von Ossietzky Universität Oldenburg , Oldenburg , Germany.
Birger
B
Kollmeier
a Department of Otorhinolaryngology , Kuopio University Hospital , Kuopio , Finland ;|b Institute of Clinical Medicine, University of Eastern Finland , Kuopio , Finland ;
Aarno
A
Dietz
D000293:Adolescent; D000328:Adult; D064368:Healthy Volunteers; D034381:Hearing Loss / Q000175:diagnosis*; D006320:Hearing Tests; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D012015:Reference Standards; D055815:Young Adult
Digit triplet test (DTT); hearing screening; signal-to-noise ratio (SNR); speech audiometry; speech recognition threshold (SRT); speech test in noise