Transcript Subject TP023 - 500 Hz ASSR

An Objective Procedure Based in Auditory
Steady State Responses for the Prescription
of Hearing Aid Features
F. Zenker Castro (1) , R. Fernandez Belda (1) , R. Mora Espino (2)
& J.J. Barajas de Prat (3)
(1) Clínica Barajas (2) Fundación Canaria Dr. Barajas para la Prevención e
Investigación de la Sordera (3) Universidad de La Laguna
SANTA CRUZ DE TENERIFE - CANARY ISLANDS - SPAIN
Universidad de
La Laguna
NHS 2008 Conference Villa Erba Congress Center, Cernobbio (Como Lake), Italy - June 19-21, 2008
FACTS ABOUT HEARING AID
FITTING IN NEWBORN BABIES
• It is very comon that at this age the only evidence that we
have of the hearing sensitivity is an Auditory Evoked Potential
Test.
• Most of us rely upon software-assisted automatic hearing aid
fittings.
• In order to introduce the hearing threshold in this software we
need to estimate a conventional audiogram (dB HL) from the
physiological response (dB nHL).
Yi  Yi (Yi  Yi)
True Physiollogical
Response
Real Physiollogical
Response
= 20 dB!!!
Error Estimation
Loudness Perception Map
ASSR Recordings
PREDICTION OF LOUDNESS GROWTH
FUNCTION FROM THE ASSR
Y = 0.75X0.4
Predicted Loudness (fo) = B0 + B1 * Intensity + B2 * Amplitude
Zenker Castro, Franz, Juan Barajas de Prat, Jose and Larumbe Zabala, Eneko (2008). Loudness and auditory steady-state
responses in normal-hearing subjects. International Journal of Audiology, 47:5, 269 — 275.
Prescription of hearing aid features
(Subject TP023 - Right ear)
Loudness Perception Map
predicted from ASSR
ASSR Recording
loud speech
average speech
soft speech
Y = 0.75X0.4
PHYSIOLLOGICAL HEARING THRESHOLD
dB HL
500
1000
2000
4000
45
50
60
65
Dynamic Range
(Subject TP023 - 500 Hz ASSR - Right ear)
Zenker F. & Barajas J.J.(2008). ASSRs: Their role in hearing device fitting. In: The Auditory Steady-State Response: generation,
recording & clinical application. Edited by Gary Rance. In press.
Dynamic Range
(Subject TP023 - 500 Hz ASSR - Right ear)
Zenker F. & Barajas J.J.(2008). ASSRs: Their role in hearing device fitting. In: The Auditory Steady-State Response: generation,
recording & clinical application. Edited by Gary Rance. In press.
Dynamic Range
(Subject TP023 - 500 Hz ASSR - Right ear)
Zenker F. & Barajas J.J.(2008). ASSRs: Their role in hearing device fitting. In: The Auditory Steady-State Response: generation,
recording & clinical application. Edited by Gary Rance. In press.
Dynamic Range
(Subject TP023 - 500 Hz ASSR - Right ear)
57
84
Zenker F. & Barajas J.J.(2008). ASSRs: Their role in hearing device fitting. In: The Auditory Steady-State Response: generation,
recording & clinical application. Edited by Gary Rance. In press.
Average Gain
(Subject TP023 - 500 Hz ASSR - Right ear)
NORMAL HEARING
HEARING IMPAIRED
57 (Hearing Threshold)
40 (Lower Limit Speech)
G = (57-40) =17 dB
Zenker F. & Barajas J.J.(2008). ASSRs: Their role in hearing device fitting. In: The Auditory Steady-State Response: generation,
recording & clinical application. Edited by Gary Rance. In press.
Compression
(Subject TP023 - 500 Hz ASSR - Right ear)
NORMAL HEARING
HEARING IMPAIRED
84 (Upper Limit Speech)
57 (Hearing Threshold)
C = (84-57)/(80-40)
C = 27/40
C = 0.67
Zenker F. & Barajas J.J.(2008). ASSRs: Their role in hearing device fitting. In: The Auditory Steady-State Response: generation,
recording & clinical application. Edited by Gary Rance. In press.
Maximum Ouput
(Subject TP023 - 500 Hz ASSR - Right ear)
MPO = [Loud – B0 – (B2*Amplitude)]/B1
Barajas de Prat, J.J., Zenker Castro, F., Mora Espino, R. and Fernández Belda, R. Prediction of Uncomfortable Loudness Levels
in Normal Hearing Adults from the Auditory Steady State Responses. Paper presented at the XXIX International Congress of
Audiology, Hong Kong, June 8 - 12, 2008.
Input – Ouput function
(Subject TP023 - Right ear)
Zenker F. & Barajas J.J.(2008). ASSRs: Their role in hearing device fitting. In: The Auditory Steady-State Response: generation,
recording & clinical application. Edited by Gary Rance. In press.
Comparison of REAG using the Nal-NL1,
DSL v 4.1 and ASSR-PF
(Subject TP023 - Right ear)
(*) ASSR-PF = Auditory Steady State Response Prescription Formulae
Conclusions
• ASSR-PF can be a first step in fitting hearing
aids to newborn babies.
• The ASSR-PF enable determinations of basic
hearing aid properties such as: Gain,
Compression and Maximum Output.
• Limitations of the ASSR-PF:
– High variability of the amplitude of the ASSR.
– Differences in the amplitude-intensity function
between adults and newborn babies.
– Our reference group is based on normal hearing
adult subjects.
Thank you very much
for your attention
WELCOME!
EFAS 2009
TENERIFE
SPAIN