Transcript Extremely low gestation infants are at high risk for auditory neuropathy

Extremely low gestation
infants are at high risk for
auditory neuropathy
Lynn M. Iwamoto, MD; Konstantine Xoinis, MD; Yusnita Weirather, MA,
CCC-A; Hareesh Mavoori, PhD; Steven Shaha, PhD
Kapiolani Medical Center for Women & Children, Hawaii Pacific Health
Center for Health Outcomes
Honolulu, Hawaii
Faculty Disclosure Information
•
In the past 12 months, I have not had a
significant financial interest or other relationship
with the manufacturer(s) of the product(s) or
provider(s) of the service(s) that will be
discussed in my presentation.
•
This presentation will not include discussion of
pharmaceuticals or devices that have not been
approved by the FDA.
Auditory Neuropathy
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
Auditory dys-synchrony (AD)
Transmission of sound to the brain is
abnormal
Abnormal brainstem evoked responses (ABR)
 Normal acoustic emissions (OAE)
 Preserved cochlear microphonics
 Acoustic reflex absent
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
May be missed with OAE screening
Auditory Neuropathy
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Pathophysiology
Cochlear inner hair cells
 Neural pathways: CN VIII
 Brainstem

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Speech perception is impaired
Fluctuating losses
 Difficulty in background noise
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Prognosis is unpredictable
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Optimum management is unclear
High risk neonates
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Sensorineural hearing loss is 10 times
more prevalent
Auditory neuropathy (AN)
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Rance, et al 1999
1991-1996
 5199 infants screened (at risk population)
 2.3/1000 AN
 11% of 109 SNHL
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
Berg, et al 2005
Mar 2002-Dec 2003
 24.1% of 432 NICU (regional perinatal center)
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Risk Factors
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Family history
Prematurity
Hyperbilirubinemia
Ototoxic medications
Hypoxia
Hydrocephalus
Meningitis
Objectives

Establish prevalence rate for auditory
neuropathy in the high risk nursery

Differentiate infants with auditory
neuropathy from those with cochlear
hearing loss
Patient Population

Retrospective review
1999-2003
 Kapiolani Medical Center for Women and
Children Newborn Special Care Unit
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Sensorineural hearing loss
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Auditory neuropathy
Gestational age-matched controls
Data Collected
Demographics
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Gestational age
Birthweight
Gender
Ethnicity
Apgar scores
Severity of illness
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Length of hospitalization
Chronic lung disease
Intraventricular hemorrhage
Necrotizing enterocolitis
Data Collected
Risk Factors

Medications
Furosemide
 Aminoglycosides
 Vancomycin
 Dexamethasone


Infections
CMV
 Toxoplasmosis
 Meningitis

Data Collected
Risk Factors
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Mechanical ventilation
Conventional ventilation
 High frequency ventilation
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Hyperbilirubinemia
Pulmonary hypertension

Nitric oxide
AN vs SNHL vs Control
AN/AD
SNHL
Control
(24)
(71)
(92)
28±5†
33±5
32±5
1318±894†
1968±1006
1872±996
58
61
53
1 min apgar
4.8±2.5
6.1±2.2
5.6±2.3
5 min apgar
6.7±1.6
7.7±1.7
7.3±1.7
117±76*†
73±89*
40±62
Gestational age (wks)
Birthweight (g)
Male gender (%)
Length of
hospitalization (d)
*p<0.05 vs. Control
†p<0.05 vs. SNHL
Gestational Age Distribution
High Risk Nursery 1999-2003
PREVALENCE
By Gestational Age Group
Exposure to Medications
AN/AD
SNHL
Control
(%)
(%)
(%)
Aminoglycoside
s
Furosemide
95.8*
80.3
70.7
95.8†*
50.7*
32.6
Vancomycin
79.2†*
41.4
27.2
Dexamethasone
54.2*
32.4*
14.1
*p<0.05 vs control
† p< 0.05 vs SNHL
Neonatal Morbidities
Peak Bilirubin
(mg/dl)
Ventilation (d)
HFOV (%)
CMV Infection (%)
*p<0.05 vs Control
AN/AD
SNHL
Control
12.7±4.2
13.1±6.3*
10.0±3.5
45±42*
28±31
19±29
16.7
28.2*
8.7
0
7.0*
0
Neonatal Morbidities
AN/AD
SNHL
Control
(%)
(%)
(%)
BPD
66.7†*
30.0*
23.9
IVH
16.7
9.9
3.3
Hydrocephalus
4.2
8.5
3.3
NEC
8.3
8.5
3.3
* p<0.05 vs. control
† p < 0.05 vs. SNHL
Summary
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SNHL = 21/1000 in the NICU
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AN/AD = 5.3/1000
26% of hearing loss
 2/3 were ≤ 28 wks gestation
 44% of hearing loss for those ≤ 28 wks
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Summary
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AN/AD vs. SNHL
Younger gestation
 Lower birthweight
 Greater exposure to potential ototoxic
medications
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Furosemide
 Vancomycin
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Higher incidence of BPD
 Longer hospitalization
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Conclusions
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Auditory neuropathy is a significant
problem in the high risk nursery
population.
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Extremely premature infants are at highest
risk.
Perspective
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Infants in the high risk nursery should be
routinely screened by both ABR and OAE
before hospital discharge.
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Early identification of AN/AD will lead to a
better understanding of the
pathophysiology and the development of
appropriate intervention strategies.