Électronique du Mazet ECHODIA ELIOS, Руководство пользователя

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User guide
ELI O S
ECH001XN111-A4 – 07/2022
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Introduction and test setup 3.4 ASSR
3.4 ASSR
ASSR : Auditory Steady-State Responses
The Auditory Steady-State Responses ( ASSR ) is an electrophysiology measurement used to determine the hearing loss degree
with a specificity in frequency.
The sound stimuli (500Hz, 1000Hz, 2000Hz and 4000Hz) are presented with modulation frequencies sufficiently spaced so
that their physiological responses do not interfere with each other. The presentation frequency (or modulation frequency) of
the stimulation signal will be analyzed on an electroencephalogram (EEG) in order to determine the hearing threshold of the
corresponding stimulus (LINS & Picton, 1995; Lins et al., 1996) .
The response presence is determined by statistical tests which analyze the coherence of the signal (amplitude and phase)
between the different samples collected during the measurement. These tests provide objective responses with a previously
known rate of false positive. This is why they are commonly called "objective response detection" techniques (ORD) (Melges
et al., 2009).
The objective nature and the possibility to stydy a hearing threshold for each frequency indicate the ASSR as an important
tool for audiological assessment, mainly for non-collaborative individuals (children, cognitive impairment, legal procedures).
Until now, threshold research in children has been carried out using Auditory Brainstem Response (ABR) at specific frequen-
cies (Burst). The possibility of testing several frequencies at the same time without loss of specificity by using
ASSR allows
a reduction of the measurement time. In addition, statistical calculation tools, indicating the presence (or absence) of a re-
sponse, facilitate the accessibility of the test for less experienced operators, compared to the ABR, which normally involves
a subjective visual analysis of the curves.
ASSR 's results have shown great accuracy in identifying severe and profound hearing loss.
However, many authors have reported a greater variability in normal hearing volunteers and patients with mild sensorineural
loss (Han, Mo, Liu, Chen and Huang, 2006).
3.4.1 Equipment
To make a ASSR measurement you need the following equipment:
Common elements for all configurations
ELI O S
unit E
CHO
-
DIF
unit
Electrophysiology
cable
4 surface electrodes