A§E
Overview
A§E comprises 4 modules:
1. The "classical" A§E tests based on speech sounds used in:
- a two-choice (yes/no) phoneme detection test
- a phoneme discrimination test in an oddity paradigm
- a closed set phoneme identification test using a picture-pointing
response
These tests aim to assess the coding of spectral information.
All sounds that are used are phonemes that are common in many languages.
All phonemes have equal durations and were rms-balanced in the
beginning(*), but corrections based on subjective
loudness balancing have been made by 30 normal hearing volunteers. For the discrimination
and identification tests intensity roving is applied in a range
of ±3 dB(**), meaning that a random gain ranging
from -3 dB to +3 dB is applied to a given phoneme when it is presented. This should
eliminate the intensity cues that still remain after all this equalizing and due
to the persisting differences in the temporal profile of different phonemes.
2. The intonation tests consisting of:
- The prosody tests: sentence intonation and word stress
pattern
- Three same/different tests with synthetic sounds: harmonic complexes,
harmonic intonating sounds and disharmonic intonating
sounds
These tests aim to assess the low frequency coding with special interest for the
temporal fine structure coding.
They contain low frequency spectral cues, basically differences of the fundamental
frequency ∆F0, either alone or in combination with differences of the corresponding
harmonics 2F0, 3F0 and 4F0. The reference F0 = 200 Hz for all tests. The presentation
level is 70 dB SPL with roving of ±3 dB.
3. The loudness scaling test
This test aims to assess the intensity coding.
It consists of a typical loudness scaling task at 250, 1000 and 4000 Hz, assessing
the loudness growth function of the (aided) cochlea. The test stimuli are narrow
band noises centered at 250, 1000 and 4000 Hz presented at different levels. The
results provide useful feedback for the programming of the hearing device (hearing
aid or cochlear implant).
4. Localization test
This test aims to assess the central integration
of binaural stimulation with cochlear implants.
It is a binaural localization test for which only 2 loudspeakers are required. It
is based on interaural level differences (ILD’s) roving around presentation levels
of 60 dB SPL. The localization test assesses the localization capacity of the listener,
giving an indirect view on the central integration of the binaural signal.
(*) Only the explosives /p/, /t/, /k/, /b/ and /d/ are not loudness balanced and
are shorter in duration. They have been added as a test tool to be used by the audiologist
at his/her own discretion
(**) The range of the roving depends slightly on the type of soundcard used, but
should be close to ±3 dB