Download ASSRs

UPDATING OF THE
ELECTROPHYSIOLOGICAL
RESPONSE IN THE NEWBORNS
José Juan Barajas de Prat
ICA 2010 Sao Paulo, Brazil
March 28 th – April 1 st
WHAT SHOULD THE IDEAL INFANT
HEARING ASSESSMENT?
Must be applicable to neonates and
children
 Measure Hearing sensitivity from 250-8
kHz
 Assess hearing sensitivity for mild to
severe- profound hearing loss
 Objectively detect an infant´s response to
sound

ELECTROPHYSIOLOGIC TECHNIQUES
Click and tone- burst evoked ABR
 Evoked potentials for tones that are
amplitude and/or frequency modulated

 Auditory-steady
state responses (ASSR)
AMLR and 40 Hz
 Cortical AEPs

LIMITATIONS OF CONVENTIONAL
EVOKED POTENTIAL TESTS

Click ABR:


TB-ABR:


Cannot be used to estimate the 4 frequency (500-4000 Hz)
audiogram
Lenghtly procedure, relies on subjective analysis of
waveforms
AMLR, 40 Hz and CAEP:


Unreliable during natural or sedated sleep on infants and
children
CAEP methods with quietly awake infants may hold promise
for estimates of thresholds and speech feature discrimination
abilities
Jose J. Barajas. (1985). Auditory Brainstem and Middle Latency Response in Early
Detection of Hearing Loss in Infants. New dimensions in otorhinolaryngology – head and
neck surgery (1); pp 289-292.
CLICK
PIP (0.25, 0.5, 1, 2, 4 kHz)
STIMULI AND GENERATION
OF THE MLR 40 HZ
25 ms, 40 Hz
V
Pa
N0
(N10)
MLR 40Hz
0
25
50
75
100ms
40 Hz
Jose J. Barajas. (1988). Middle Latency and 40 Hz Auditory Evoked Responses in normal
hearing children: 500 Hz thresholds.Scand Audiol Supp 30:99-104
MEASUREMENTS OF SIGNAL AND NOISE AT
DIFFERENT RATES
Picton TW, John MS, Dimitrijevic A, Purcell D. Human auditory steady-state responses. Int J
Audiol. 2003 Jun;42(4):177-219.
ORIGIN SSR (Herdman et al, 2002)
88 Hz
Cz
39 Hz
7
1
5
3
1
2
R
3
Cz
4
5
0
3
1
28
ms
0
28
ms
6
2
L
6
4
AUDITORY STEADY STATE
RESPONSE (ASSR)
Can be recorded in neonates and children
 Are evoked by frequency –specific tonal
stimuli
 Correlate with elevation in the hearing
thresholds
 Can be objectively evaluated
 Are used to estimate an audiogram

OPTIMAL MODULATION RATE FOR EACH CARRIER
500 Hz
1500 Hz
4000 Hz
Rickards FW, Tan LE, Cohen LT, Wilson OJ, Drew JH, Clark GM. (1994). Auditory steady-state
evoked potential in newborns. Br J Audiol.;28(6):327-37.
THE NEONATAL ASSR
AVERAGED AMPLITUDE FOR NORMAL- HEARING
INFANTS AND ADULTS
Luts H, Desloovere C, Wouters J.2006. Clinical application of dichotic multiple-stimulus auditory
steady-state responses in high-risk newborns and young children. Audiol Neurootol.;11(1):24-37.
ASSR THRESHOLD IN BABIES
Luts, H. “Diagnosis of Hearing Loss in Newborns. Clinical Application of Auditory
Steady- State responses”. Director: Prof. Dr. J. Wouters . Katholieke Universiteit Leuven,
Faculty of Medicine, 2005
ASSR THRESHOLD CHANGES IN INFANCY
Rance, G. & Tomlin, D. (2006). Maturation of ASSR in nomal babies. Ear & Hearing,
27, 20-29.
ASSRs IN HEARING IMPAIRED BABIES
Rance G (2008). ASSR in Neonates & Infants. In The Auditory Steady-State
Response: Generation, Recording, and Clinical Applications. Edited by Gary Rance.
In review.
CONCLUSION
Maturation factors affect ASSR.
 Normally hearing babies present lower
amplitudes than adults and older children.
 Neonatal period threshold higher and
more variable.
 Need to determine typical response levels
for babies of different ages and
developmental stages.


AEP and early hearing aid fitting and validation
ASSR
 CAEP (Obligatory Cortical Auditory Evoked
Potentials)


AEP: Cochlear Implants Evaluation
LOUDNESS AND ASSR
Zenker Castro F., Barajas de Prat JJ & Larumbe Zabala E. (2008): Loudness and
Auditory Steady State responses in normal hearing subjects. Int J Audiol. 2008
May;47(5):269-7.
LOUDNESS MAP
ASSR
Zenker F. & Barajas J.J. ASSRs: Their Role in Hearing Device Fitting. In: Gary Rance, editor. The
Auditory Steady-State Response: Generation, Recording & Clinical Application. San Diego: Plural
Publishing; 2008. p. 241-263.
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.
Subject TP023 - Right ear
Loudness Perception Map
predicted from ASSR
ASSR Recording
loud speech
average speech
soft speech
Y = 0.75X0.4
dB HL
500
1000
2000
4000
45
50
60
65
HEARING AID PRESCRIPTION
FROM ASSR
Zenker F. & Barajas J.J.(2008) ASSRs: Their role in hearing device fitting. In: The
Auditory Steady State response: generation, recording and clinical application. Edited
by Gary Rance.
Why are we using obligatory cortical
responses to evaluate hearing aid function?




More likely to correlate well with perception.
Can be elicited by a range of speech phonemes.
Reliable present in awake young infants.
Can be present in children with auditory
neuropathy/dys-synchrony.
CAEP
Suzanne C. Purdy et al. (2004). Aided cortical auditory evoked potentials for hearing
instrument evaluation. 3rd Pediatric Conference “A Sound Foundattion through early
amplification”. Chicago, Illinois
MATURATIONAL EFFECTS ON CORTICAL EVOKED
RESPONSE
Ponton et al. (2000) Maturation human central auditory system activity: evidence from
multi-channel evoked potentials. Clinical Neurophysiology 111 (2): 220-236
EFECTO OF AGE OVER THE LATE RESPONSES
Barajas JJ (1990) The effects of age on human P3 latency. Acta
Otolaryngol Suppl;476:157-60.
F Zenker & J J Barajas (1999) Auditory P300 development from
an active, passive and single-tone paradigms., 99-111.
International Journal of Psychophysiology 33 (2).
CAEP CAN ELICITED BY DIFFERENT SPEECH
PHONEMES IN NEWBORNS
D. KURTZBERG 1989
CAP (P1)
Amplitud (µV)
20.0
10.0
0.0
-10.0
-100.0
0.0
100.0
200.0
300.0
Latencia (mseg)
400.0
500.0
CAP (P1)
Amplitud (µV)
20.0
10.0
0.0
-10.0
-100.0
0.0
100.0
200.0
300.0
Latencia (mseg)
400.0
500.0
CAP (P1)
P1
Amplitud (µV)
20.0
10.0
0.0
-10.0
-100.0
0.0
100.0
200.0
300.0
Latencia (mseg)
400.0
500.0
P1 IN HEARING AIDS
Anu Sharma, Emily Tobey, Michael Dorman, Sneha Bharadwaj, Kathryn Martin, Phillip Gilley, Fereshteh Kunkel. Central
Auditory Maturation and Babbling Development in Infants With Cochlear Implants. ARCH OTOLARYNGOL HEAD
NECK SURG/VOL 130, MAY 2004.
P1 IN COCHLEAR IMPLANTS
Anu Sharma, Michael F. Dorman, Andrej Kral. (2005). The influuence of a sensitive
period on central auditory development in children with unilateral and bilateral cochlear
implants. Hearing Research 203, 134–143.
BRASIL
ASSR & TONE-BURST ABRs IN NEONATES
Rance G (2008). Assr in Neonates & Infants. In Auditory Steady-State Response
Generation, Recording, and Clinical Applications. Gary Rance
Average
Stimuli
EEG
FFT
SSR Recordings
Thresholds
Right
Left
Modulation Frequency (Hz)
CONCLUSION




Maturation factors affect ASSR.
Normally hearing babies present lower
amplitudes than adults and older children.
Neonatal period threshold higher and more
variable.
Need to determine typical response levels for
babies of different ages and developmental
stages.