Download auditory neuropathy spectrum disorder*** Auditory Neuropathy

Auditory Neuropathy Spectrum Disorder:
Issues in Diagnosis and Management
Thierry Morlet, PhD
[email protected]
Overview of Auditory Neuropathy
Definition
 Auditory neuropathy is a relatively recent clinical diagnosis.
 Describe individuals with auditory disorders due to dysfunction of the
inner hair cells, of the synapses between the inner hair cells and the
auditory nerve, and/or the auditory nerve.
 Unlike patients with sensory hearing loss who show clinical evidence of
impaired outer hair cell function, patients with auditory neuropathy show
clinical evidence of normally functioning outer hair cells.
 Individuals with auditory neuropathy typically demonstrate impaired
speech understanding, and show normal to severely impaired speech
detection and pure tone thresholds.
 Auditory neuropathy affects an individual’s ability to process rapidly
changing acoustic signals, known as auditory temporal processing.
Auditory Neuropathy Spectrum Disorder
Patients with outer hair cell responses and absent/abnormal
auditory brainstem responses, are classified as having:
- AN: auditory neuropathy*
- AN/AD: auditory neuropathy/dys-synchrony**
- ANSD: auditory neuropathy spectrum disorder***
* Starr A, Picton TW, Sininger Y, Hood LJ, Berlin CI. 1996. Auditory neuropathy. Brain, 119:741-753.
** Berlin C, Hood L, Rose K. 2001. On renaming auditory neuropathy as auditory dys-synchrony: Implications
for a clearer understanding of the underlying mechanisms and management options. Audiology Today 13:15-17.
*** Auditory neuropathy consensus conference. J Gravel, 2008, Como, Italy
Auditory Neuropathy
Auditory Neuropathy/Dys-synchrony
Auditory Neuropathy Spectrum Disorder
 Clinical Presentation
 Problems listening in noise, fluctuation, delayed speech/ language
development
 Physiologic Responses
 Hair Cell Responses
 Present otoacoustic emissions
 Present cochlear microphonics
 Neural Responses
 Absent auditory brainstem responses
 Absent middle ear muscle reflexes
 No suppression of otoacoustic emissions
 Behavioral Responses
 Variable audiometric configurations
 Variable but generally poor speech recognition
What is the occurrence of ANSD?
•
About 1 in 10 patients with desynchronized ABRs will have OAEs and/or
cochlear microphonics.
•
This prediction is based on research from:
•
Berlin, Hood, Morlet, Keats et al., 2000 – Of 1000+ children screened in
schools for the Deaf, 10-12% had either robust OAEs or evidence of
residual OHC function.
•
Lee et al., 2001 - Of 72 students at schools for hearing-impaired,
approximately 10% had either robust OAEs or evidence of OHC
responses.
•
Rance et al., 1999 – 1 in 9 infants with permanent hearing loss had
cochlear microphonics but no ABR.
•
Sininger, 2002 – Approximately 10% of infants had OAEs and no ABR in
the NIDCD Newborn Screening Study.
Outer Hair Cells
MOTION AMPLIFIERS
OUTER HAIR CELLS
MISSING
IHCs OK
Inner Hair Cells (IHC)
SEND NEURAL PULSES TO THE BRAIN
(a) NORMAL
HEARING
(b) SENSITIVITY
LOSS
Harrison RV. An animal model of auditory neuropathy.
Ear & Hearing. 19(5):355-61, 1998 Oct
Special thanks to Mead
Killion,Ph.D.
OHCs OK
INNER HAIR CELLS
MISSING
(c) CLARITY
LOSS
Auditory Neuropathy Spectrum
Disorder
Characteristics and Epidemiology
Age of presentation
 2 distinct age groups:
– Early onset (majority of patients)
 neonatal insult
– Some subjects develop the ANSD condition in
adolescence or early adulthood.
 Generalized neuropathy
 Peripheral neuropathy
 Acquired (head trauma)
ANSD Database:
Ears Affected
 Bilateral: 92.9%
 Unilateral: 7.1%
Bilateral
Unilateral
Multiple etiologic factors involved
 No true “cause” identified, though multiple
risk factors are known to exist:
–
–
–
–
–
Perinatal factors
Genetic factors
Inner ear malformations
CNS malformations
Immune disorders
Perinatal factor – CNS immaturity
 ELBW infants are at elevated risk for both
SNHL and ANSD
 Compared with infants with SNHL, infants
with ANSD are younger (GA 28.3 vs 32.9
weeks) and smaller (BW 1318 vs 1968
grams), with longer hospital stays (Xoinis et
al, 2007)
Perinatal factor – Hyperbilirubinemia
 Bilirubin selectively damages brainstem
auditory nuclei, the auditory nerve, and
spiral ganglion cells (Shapiro et al, 2001),
which can undermine the temporal coding
of auditory information (Shaia et al, 2005)
 Berlin et al (2010) noted 48.8% of 150
patients with ANSD had hyperbilirubinemia
(47.7% premature, 20.3% exchange
transfusion)
Perinatal factor - Others
 Ototoxins – vancomycin, decadron
 Anoxia, hypoxia, cerebral palsy
 Intracranial hemorrhage, traumatic brain
injury
 Mumps
Genetic factors
 Some families with ANSD in multiple
members
 May be syndromic or non-syndromic
 Many patterns of inheritance: dominant,
recessive, mitochondrial, and x-linked
 Two main genes are presently of interest:
OTOF and DFNB-59
Otoferlin (OTOF)
 Locus 2p23.1
 Expressed in IHC, possible role in membrane
trafficking and/or IHC synaptic vesicle function
 Nonsyndromic prelingual moderate-profound
sensorineural hearing loss
 At least 42 pathologic mutations of OTOF
known to cause this phenotype, some
temperature sensitive
 Speech comprehension is severely impaired
Pejvakin (DFNB 59)
 Locus 2q31.1-q31.3
 Pejvakin is distributed in the cell bodies of
neurons in the spiral ganglion and
brainstem auditory nuclei
 Nonsyndromic prelingual sensorineural
hearing loss
 Can have ANSD or non-ANSD phenotype
Other genetic causes
 Charcot-Marie-Tooth
 Waardenburg syndrome
 Leber’s hereditary optic neuropathy
 Mohr-Tranebjærg syndrome
 Autosomal dominant optic atrophy
 Many other candidates
Inner ear malformations
 Huang et al (2010) evaluated MRI scans of
103 children with ANSD
All
N = 103
71 (68.9%)
15 (14.6%)
11 (10.7%)
7 (6.8%)
6 (5.8%)
1 (1.0%)
12 (11.7%)
28 (27.2%)
CNS malformations
 Huang et al (2010) evaluated MRI scans of 103
children with ANSD
All
N=103
66 (64.1%)
37 (35.9%)
7 (6.8%)
13 (12.6%)
19 (18.4%)
18 (17.5%)
Immune disorders
 Guillain Barre syndrome is an autoimmune
inflammatory demyelinating
polyneuropathy, usually triggered by an
acute infectious process
– Involvement of the peripheral nervous system
and has been associated with ANSD
History and Risk Factors (153 pediatric patients)
Normal history
Normal pregnancy
Premature birth
Hyperbilirubinemia
Exchange transfusion
Anoxia
Respiratory distress
Artificial ventilation
Ototoxic drugs
Low birth weight
Anemia
Number (Percent)
28 (18.3%)
31 (20.3%)
73 (47.7%)
74 (48.4%)
31 (20.3%)
26 (17%)
23 (15%)
35 (22.9%)
44 (28.8%)
11 (7.2%)
6 (3.9%)
Berlin, Hood, Morlet et al., 2010
Varieties of ANSD
 50% of patients have no defined etiology
 Genetic factors: 40%
 Toxic-metabolic (anoxia, hyperbilirubinemia),
immunological (drug reaction, demyelination),
infectious disease (post viral): 10%
 Rare cases of head injury (children and adults)
 Some forms of ANSD may be progressive
 Some forms of ANSD may also involve OHC functions
Auditory Neuropathy Spectrum
Disorder
Diagnosis
Pathophysiology
 ANSD with quite similar physiological and
audiological findings can occur as a
consequence of:
– pathology of IHC,
– their synapses,
– and/or the auditory nerve
Middle Ear Muscle Reflexes
Percent
Absent MEMRs (all absent)
Bilateral AN/AD
Unilateral AN/AD
84.67
5.33
Total Absent
90.00
Abnormal (combination of elevated and absent)
Bilateral AN/AD
8.67
Unilateral AN/AD
1.33
Total Abnormal
10.00
(number of subjects)
From Berlin, Hood et al., 2010
No MEMR
Some MEMR
Tests Results: Efferent Neural Function
Middle Ear Muscle Reflexes
Stimulus Ear:
Right
Ipsilateral
500
Patient
1
A
2
105
3
A
4
A
5
ND
6
105
7
A
8
95
95
9
100
10
100
11
105
12
110
13
A
14
90
15
ND
1000
2000
4000
Contralateral
500
1000
2000
4000
A
105
A
A
ND
105
A
105
100
95
95
A
110
A
85
ND
A
A
A
A
ND
A
A
A
A
A
A
A
A
A
ND
A
A
ND
A
ND
A
ND
A
A
A
A
ND
A
A
ND
110
105
ND
110
100
A
110
100
A
A
ND
110
110
90
115
A
A
ND
110
A
A
A
A
A
A
ND
A
A
A
A
A
A
ND
A
A
A
ND
A
A
A
ND
ND
A
A
A
Absent MEMRs (all absent)
90%
Abnormal (elevated/absent)
10%
A
100
ND
105
110
A
110
A
A
A
ND
110
A
85
A
No MEMR
Some MEMR
From Berlin, Hood, Morlet et al., 2005
OAEs in ANSD
 OAEs are usually normal or near normal in individuals with
ANSD.
 Absence of OAEs in ANSD:
–
–
–
–
–
due to a conductive issue (external and/or middle ear)
ototoxic drugs (antibiotics, chemotherapy)
aging, noise (hearing aid)
mixed type of hearing loss
due to ANSD
OAE test results
Percent
Left Ear
Present
Absent
Partial/Questionable
76.19
16.88
6.93
Right Ear
Present
Absent
Partial/Questionable
75.22
15.93
8.85
From Berlin, Hood, Morlet et al., 2010
ABR and Cochlear Microphonics
(CM - electrical responses generated in part by
the outer hair cells)
Normal ABR to condensation and rarefaction
clicks; CM inverts - neural components do
not.
ANSD patient - all CM, no
neural response
Auditory Brainstem Responses
 Distinguish the cochlear microphonic from
neural responses.
 The ABR is markedly abnormal in
individuals with ANSD. Recordings might
appear as
– 1) a “flat” ABR with no evidence of any peaks or
– 2) some poorly synchronized but evident later
peaks (wave V) that appear only to stimuli at
elevated stimulus levels (in about 25% of
patients).
Neural
Synchrony
Stimulus
Envelope
Single Unit
Discharges
Compound
Action
Potential
Changes in neural firing patterns can account for
reduced or dys-synchronous responses
Single Unit
Discharges
Compound
Action
Potential
Starr, 2001
Cochlear Microphonic (CM)
 Cochlear microphonic provides a valid measure of hair cell
function.
 CM generally remain present in individuals with ANSD
despite loss of OAEs.
 Appropriate identification of the CM will help in evaluating
outer hair cell function in patients who have lost or never
had OAEs and it will help evaluate outer hair cell function in
cases of middle ear effusion when the recording of OAEs is
not possible.
 CM can become attenuated and difficult to detect when
patients are over the age of 50 years.
CM in normal subjects
Associated Disorders and Differential
Diagnosis
“What other auditory problems might ‘look like’
ANSD, based on similar test results?”
Associated Disorders and Differential
Diagnosis
 Cochlear Nerve Deficiency
AI duPont Database
 32 children (out of 160+) were identified with MRI
evidence of cochlear nerve dysplasia (CND).
 Three were affected bilaterally.
 60% of unilateral cases occurred on the left side.
 Other inner ear anomalies were found in 50% of
patients including all patients with bilateral CND.
 The majority of these 32 patients tested had an
audiometric profile of ANSD (absent MEMR, present
OAEs/CM, absent ABR).
Absent or hypoplastic auditory nerves are not uncommon and
these cases usually resemble ANSD when OHC are present and
functioning.
Unilateral Auditory Neuropathy
Imaging studies
 Imaging studies are useful in evaluating hearing loss
to diagnose inner ear malformations as well as to
check for presence and size of the auditory nerve.
 Absent or hypoplastic auditory nerves are not
uncommon (Buchman et al., 2006) and these cases
usually resemble ANSD when OHC are present and
functioning.
 Audiological management in these patients is
problematic because a cochlear implant cannot work
when the nerve is absent and might not work well
when the nerve is hypoplastic.
 An MRI does not give the full picture!
Associated Disorders and Differential
Diagnosis
 Cochlear Nerve Deficiency
 Friedreich Ataxia
Friedreich Ataxia may look like ANSD
 Dys-synchrony
 Gap detection affected as well
 Brain still able to process language for a
while (but in good conditions only, i.e.,
without background noise).
 Dys-synchrony occurs after acquisition of
language (ANSD which mostly affects preverbal infants).
Rance et al., 2010
Associated Disorders and Differential
Diagnosis
 Cochlear Nerve Deficiency
 Friedreich Ataxia
 Enlarged Vestibular Aqueduct
EVA: Definition
 EVA is the most common radiological abnormality seen in
children with SNHL: 5-15% of children with SNHL have EVA.
 EVA can be associated with other congenital ear anomalies,
such as a hypoplastic cochlea.
 Studies suggest that most children with EVA will develop
some degree of hearing loss.
 SNHL onset may occur from birth to adolescence, usually
during childhood and may be precipitated by various factors
such as head trauma. Hearing loss is often progressive and
can fluctuate.
 Vestibular and balance disorders can also be associated.
 Children with an EVA present with a wide variety of
audiometric thresholds and physiologic measurements.
Audiometric Pattern
 Agreement between EVA side and HL (60%)
 Agreement between different audiological tests:
–
–
–
–
–
OAEs
ABRs
MEMRs
PTA
Speech
Bilateral EVA
125
250
500
0
20
30
R
L
2
[ R ]
[
10
1
L
R
]
L
4
[ R ]
8
L
L
L
R
L
[ R
L ]
40
50
60
70
Normal MEMRs
80
90
100
110
120
Subject 037
Subject 006
Bilateral EVA, Unilateral HL
125
250
500
1
2
4
8
0
10
L
20
30
L
L
L
L
L
L
40
Normal MEMR
LE
Absent MEMR
RE
50
R
60
70
80
R
R
R
90
R
100
110
120
Subject 022
R
R
R
Unilateral EVA and Bilateral HL 4/44
LE EVA
Subject 015
Absent MEMRs
and OAEs bilaterally
Subject 030
ANSD Pattern LE EVA
Subject 004
Present CM, Absent ABR
ANSD Pattern LE EVA
Subject 037
EVA
 Phenotypic expressions associated with EVA are
heterogeneous to include the following
possibilities:
–
–
–
–
normal hearing
total deafness
progressive sensorineural hearing loss
fluctuating sensorineural hearing loss or sudden
sensorineural hearing loss, sometimes subsequent to head
trauma.
– There is not always agreement between OAEs, ABRs,
MEMRs, PTA & speech scores.
Other Candidates?
 Slitrk proteins control neurite
outgrowth and regulate synaptic
development.
 Slitrk6 plays a role in the
survival and innervation of
sensory neurons in the inner ear
and vestibular apparatus.
Slitrk6
 Associated with cochlear
dysfunction attributed to
outer hair cell disease and an
auditory neuropathy
spectrum disorder in humans.
Associated Disorders and Differential
Diagnosis
 Cochlear Nerve Deficiency
 Friedreich Ataxia
 Enlarged Vestibular Aqueduct
 (Central) Auditory Processing Disorders
ANSD and CAPD
 Different etiologies
 But both share similarities
 Can be confused unless appropriate testing
is used
 Treatment is not the same
Auditory Processing Disorders
 In children, auditory processing disorder (APD) presents as
difficulty processing speech despite audiometrically normal
hearing.
 Commonly, this difficulty is most pronounced in the
presence of competing background noise, which,
unfortunately, represents most typical real-world listening
situations.
 The causes of (C)APD are not known, and in all likelihood,
(C)APD as broadly defined represents a family of auditory
processing deficits stemming from multiple causes.
Clinical Presentation
 MEMR present and in the normal range
 OAE present
 Suppression of OAEs present
 Normal ABR (to a click)
 Normal speech in quiet
 Impaired speech in noise
 Deficits related to auditory percepts
dependent in temporal cues
Illustrative Case
 Normal birth and medical history
 11 months: ENT for ear infections
 Babbling at 12 months
 14 months: 1st set of tubes
 1st true word at 18 months
 22 months: 2nd set of tubes
 3 years: ENT for speech delay. Failed most of her 1st grade
classes
 Soundfield audiogram indicated normal hearing thresholds in at
least the better ear. Speech therapy recommended
 7 years: Audiology for CAPD evaluation
 Fluctuations in achievement (good/bad weeks)`
APD suspected: Importance of the triage
ANSD vs APD
ANSD
APD
Normal
Normal
Abnormal or absent
Present
OAE
Present or absent (over
time)
Present
ABR
Abnormal or absent
Normal
Normal
Word recognition (quiet)
Normal to
severe/profound
Excellent to poor
Excellent
Word recognition (noise)
Poor
Fair to poor
Tympanogram
MEMR
Pure-tone thresholds
Auditory Neuropathy Spectrum Disorder
or (C)APD?
 Auditory Neuropathy Spectrum Disorder
– ABR, MEMR absent
– Cortical potentials can be present
– Cochlear implants a management option
 Central APD
–
–
–
–
Peripheral synchrony usually within normal limit
ABR, MEMR usually normal
Cortical potentials present
Cochlear implant not useful
Associated Disorders and Differential
Diagnosis
 Cochlear Nerve Deficiency
 Friedreich Ataxia
 Enlarged Vestibular Aqueduct
 (Central) Auditory Processing Disorders
 Neuromaturation
Neuromaturation
Hyperbilirubinemia.
Exchange Transfusion
Present TEOAEs
Normal thresholds by 7
months
Attias and Raveh, 2007
ANSD → SNHL
 Some infants are diagnosed with ANSD
right after birth.
 OAEs/CM disappear during the first few
months of life
 Behavioral responses difficult to obtain
 Can be confusing for parents.
Auditory Neuropathy Spectrum
Disorder:
Implications for Newborn Hearing
Screening
Goal: Screen all types of Hearing Loss
Outer hair cells
Inner hair cells
Auditory
nerve
INSERM, Montpelier
Promenade ‘round the cochlea
Absence of Risk Factors in ANSD
Some infants with ANSD have no risk factors and
come through the well-baby nursery.
NOT ALL infants with ANSD are found in the NICU
ANSD and Newborn Hearing Screening
 If only OAEs are used as an initial screener, 10% of
children with HL who have normal OAEs also may
have serious auditory synchrony problems.
 Similarly, if only alternating polarity or single polarity
ABR is used as an initial screener, approximately 10%
of children with flat or abnormal ABRs will have
normal OAEs and may misdiagnosed.
 Children with ANSD are currently being found more
frequently because of the proliferation of newborn
ABR-based hearing screening programs.
Protocols for Screening in Premature
Babies and Full-term Babies
 Percentage of preterms with ANSD is
higher than in fullterm babies.
 Number of ANSD patients may end up being
similar in both nurseries.
 Why would a different standard applied
to identification of sensory hearing loss
(all nurseries) and ANSD (NICU only)?
Variation in Auditory Neuropathy
Spectrum Disorder
What we have learned from our databases:
- Kresge Hearing Research Laboratory
- Vanderbilt University
- AI duPont Hospital for Children
Patient Variation:
A Continuum of ANSD
No overt delays
or auditory
complaints
until adulthood or
until first MEMRs
or ABR
1
Inconsistent auditory responses, best in
quiet, poorest in noise. Audiograms
can be misleading or fluctuate. ABR
always desynchronized, middle-ear
muscle reflexes absent. Visual phonetic
language usually
works best until cochlear implantation,
unless family prefers cultural Deafness.
5
Total lack of
sound
awareness
10
Berlin, Hood, Morlet et al., 2005
Management of Auditory Neuropathy
Spectrum Disorder:
Detection versus Discrimination in Management
and Decision-making with ANSD
Wi
thi
nN
o
No rmal
rm
al-M Limit
s
od
e ra
te
Mil
M
d-M
od ild
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Mil
d
-Se te
Mil
d-P vere
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o
Mo
Mo und
Mo derat derat
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e
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-Pr
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ofo e
un
Se
Se d
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e-P vere
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Pro und
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nd
Degree of Pure Tone Behavioral Hearing
Loss (number of ears/258)
45
40
35
30
25
20
15
10
5
0
Berlin, Hood, Morlet et al., 2009
How does it sound?
Dr. F-G Zeng
http://www.ucihs.uci.edu/hesp/Simulations/simulationsmain.htm
Kresge ANSD Database:
Speech recognition ability
Subjects over 4 years of age (n=68)
– Measurable word recognition in
quiet only (n=25)
 Average maximum word recognition
(Quiet): 45%
 Word recognition (Noise): 0%
– Word recognition in quiet and in
noise: n=5
100
Word Recognition (Percent Correct)
– No measurable word
recognition in quiet: n=38
LE
RE
80
60
40
20
0
-10
QUIET
0
10
Quiet Group (n=25)
20
QUIET
30
40 NOISE
50
60
Quiet and Noise Group (n-5)
From Berlin, Hood et al., 2010
Word recognition in quiet: ANSD
(n=22 subjects)
Note: 40 patients have 0% word recognition in quiet with
hearing sensitivity ranging from mild to severe.
Word recognition in quiet: SNHL
Data from Yellin et al. (1989) study of patients with SNHL
Word recognition in quiet: ANSD
(n=22 of 62 subjects)
= 40 of the 62 patients with 0% word recognition in quiet with
hearing sensitivity ranging from mild to severe.
The ANSD Team and Management Decisionmaking
ANSD: A Team Approach
Audiologic
- FM; Hearing aids; Monitor behaviorally; Cochlear Implant
work up based upon progress with hearing aids
Medical: Otologic (ENT), Neonatology, pediatric,
neurology
- Medical issues, imaging
ANSD: A Team Approach
Speech-Language: expressive and receptive
assessments; communication mode
- Re-evaluate every 3 months to verify 3 months
progress in 3 months time
- Yes; continue to evaluate every 3 months
- No; initiate cochlear implant work up and continue
monitoring progress
Communication Methods
 Language Development
– Is critical; work closely with speech/language pathologists,
early interventionists, educators
 Visual Communication
– Methods such as Cued speech, sign language, signed
English are important to facilitate language development.
 Auditory Verbal Therapy
– Without visual information, before cochlear implantation, has
not worked in our practice as the sole method of teaching
language.
ANSD: A Team Approach
Psychological/Developmental/Parent/Family
Counseling (Social Worker): learning abilities, family stress
indicators, cochlear implant and communication expectations
Early Intervention
Educational Contacts (Deaf Educator/Special Education
Director): school programs available, address academic and
communication needs
The audiogram cannot be the driving
force in management
 The ABRs and audiogram do not provide the
clinician with information as to the severity of
hearing impairment.
 The pure tone thresholds give indication as to the
patients’ level of sound awareness but do not
reflect the severity of the patients’ problem with
auditory timing.
 Several patients would never have been considered
as implant candidates based on the audiogram
alone.
ANSD management with FM systems
 ANSD patients generally have very poor ability to understand
speech in background noise.
 Benefit demonstrated with FM systems, particularly for patients
with residual speech understanding in quiet
 Efferent feedback function (middle-ear and olivocochlear
reflexes) is disabled
 Thought to assist in listening in noise (e.g., Liberman and Guinan, 1998)
Kresge Hearing Lab ANSD Database:
Amplification
 Variable benefit from hearing aids
– Based on data from 85 patients
Good benefit (functional interaction)
4%
Some benefit (helpful in language acquisition)
8%
Little benefit (environmental sounds)
26%
No benefit
62%
From Berlin, Hood, Morlet et al. (2010)
AI duPont Database: Hearing Aid Trials: 86
patients out of 134
Hearing Aid Benefit (86 patients)
Three Sites: 198 Hearing Aid Users
Kresge Lab ANSD Database
Cochlear Implant Outcomes
All Kresge database patients
Percent
Successful
Too soon to tell (recent CI)
Insufficient information
77.78
14.82
7.41
Only patients seen at Kresge Lab
Successful
Too soon to tell (recent CI)
Insufficient information
82.35
11.76
5.88
Based on 49 patients with ANSD
From Berlin, Hood, Morlet et al. (2010)
AI duPont: 31 Cochlear Implants
Three Sites: 99 Cochlear Implant Patients
Factors that may help in predicting
outcomes and management
 Understanding risk factors;
possible markers for delayed
neuromaturation
 Separating pre- and post dendritic
responses
From Santarelli et al., 2008
– e.g., Santarelli, Gibson, McMahon, et al.
 Cortical responses and speech
perception
From Rance et al., 2002
Cortical Potentials
 Normal maturation and functioning of
auditory cortical areas is a precondition for
normal development of speech and oral
language skills.
 Disruption of normal maturational
processes will result in diminished capacity
for speech/language acquisition.
 Cortical potentials are useful in assessing
maturation and function of the auditory
cortical areas.
Cortical Potentials: P1 latency
Sharma et al., 2011
ANSD: Issues and Challenges
 Distinguishing detection of sound and discrimination
of sound in management planning
– Isolating cochlear, synaptic, neural function
 Genetics of AN/AD, imaging, cochlear nerve agenesis, EVA
• Predicting who will develop speech/language with
little intervention
• Specific risk factors
• Protocols for recommending and fitting hearing aids,
FM systems, cochlear implants
Resources
 Listserve for parents and professionals interested in
ANSD
[email protected]
 Our Website for information and links:
www.kresgelab.com
 Links to our email addresses and lab websites
 Contributions to our database are welcome.
Colleagues at Kresge Hearing Research Laboratory and the Audiology Clinic, Department of Otolaryngology, Louisiana
State University Health Sciences Center, New Orleans, Louisiana, USA
Charles I. Berlin, PhD
Linda J. Hood, PhD
Jill Bordelon, MCD
Leah Goforth-Barter, MS
Jennifer Taylor-Jeanfreau, MCD
Li Li, MD
Kelly Rose Mattingly, MA
Sonya Tedesco, MCD
Han Wen, MSBE
Harriet Berlin, MS
Shanda Brashears, AuD
Annette Hurley Larmieu, PhD
Bronya Keats, PhD
Elizabeth Montgomery, MS
Patti St. John, MCD
Melanie Thibodeaux, MCD
Diane Wilensky, MS
The Hood Lab at Vanderbilt University: Lindsey Rentmeester AuD, Kelsey Hatton BS,
Susan Stangl BA, Heather McCaslin AuD, Christopher Spankovich AuD PhD, Andrea Hillock AuD
PhD
Vanderbilt
University
AI duPont Hospital for Children:
Ashleigh l. Greenwood, AuD
Research supported by the NIH-NIDCD, Oberkotter Foundation, Deafness Research Foundation, American Hearing
Research Foundation, National Organization for Hearing Research, Marriott Foundation, Kam’s Fund for Hearing Research,
Vanderbilt University Development Funds