Identification and Management of Infants and Young Children with Auditory Neuropathy Spectrum Disorder (ANSD)
Outline
University of North Carolina February 13, 2009
Audiological Diagnosis and Management Patricia Roush, AuD Department of Otolaryngology The University of North Carolina School of Medicine Chapel Hill, North Carolina
Diagnostic Criteria Minimum Test Battery for Diagnosis z Recommended Audiological Test Battery z Comprehensive Test Battery z Evidence re Hearing Aids and Cochlear Implants z Management Recommendations z Findings from UNC ANSD study z Case Examples z z
Pediatric Hearing Program University of North Carolina Chapel Hill z z z z z
z
Universal NB screening in NC began in 1999 300 diagnostic ABRs/year 100 hearing aid fittings/year ~115 cochlear implants/year Total 1350 infants and children – 750 using amplification – 600 with cochlear implants 140+ children with ANSD
Lessons from the Past Kalamazoo (1977) ABR/OAE testing unavailable at that time z 19 year old educated at school for the deaf z ASL primary mode of communication z Normal hearing sensitivity z Central deafness or ?ANSD z More tools available now but still many questions z z
Prevalence Disorder initially thought to be rare z Many published reports since late 90’s describing patients with similar audiologic test findings (absent ABR with present CM and/or OAEs) z Estimates range from 7-10% of children diagnosed with permanent hearing loss (Rance 2005)
Diagnostic Criteria
z
z
ANSD is characterized by normal or near normal cochlear hair cell function and absent or abnormal auditory nerve function
Terminology
Possible Mechanisms z
– Amatuzzi et al 2001 z
z
Starr et al 1996:
z
Berlin et al 2001:
z
Starr et al 2004:
– Auditory neuropathy
Selective inner hair cell loss
– Auditory neuropathy/dys-synchrony
Synaptic disorder – Starr et al 2000
z
Auditory nerve disorder
z
Myelin disorder
– Starr et al 1996
– Pre-synaptic (Type I): • When evidence of hair cell involvement exists
– Post-synaptic (Type II): • When patient has evidence of auditory nerve involvement
Terminology z
Gravel and Rapin 2006: – Sensory hearing loss (hair cells) – Auditory neuropathy (pathology of spiral ganglion cells and VIIIth nerve axons) – Central hearing loss (central auditory pathway) – Neural conduction disorder (when differentiation cannot be made)
z
Guidelines Development Conference on the Identification and Management of Infants with Auditory Neuropathy, International Newborn Hearing Screening Conference, Como, Italy June 19-21, 2008
“The Guidelines”
Gibson et al 2008: – Imaging, genetic and electrophysiologic testing should allow us to identify pathologic entities according to site of lesion – Blanket terms such as AN/AD may be more misleading then helpful
Minimum Test Battery Required for Diagnosis z
Tests of cochlear hair cell (sensory) function: – Otoacoustic emissions and/or – Cochlear microphonics
z
Tests of auditory nerve function: – Click-evoked auditory brainstem response (ABR) to high-level click stimuli
Recommended Audiologic Test Battery z z z
Otoscopic Examination Auditory Brainstem Response (ABR) Acoustic Immittance Measures – Tympanometry – Acoustic Reflex Testing
z z
z
Otoacoustic Emissions Testing Behavioral Audiometry – VRA, BOA, play audiometry Speech Recognition Testing
Comprehensive Evaluations Following Diagnosis with ANSD
Recommended Audiologic Test Battery z
Otologic z Radiologic imaging (MRI/CT) z Neurologic z Medical Genetics z Ophthalmologic z Pediatric and Developmental Evaluations z Communication Assessment z
z z
– Tympanometry – Acoustic Reflex Testing z z
z
Recommended Audiologic Test Battery z z z
17 1 Meningitis
Normal ABR
Otoscopic Examination Auditory Brainstem Response (ABR) Acoustic Immittance Measures – Tympanometry – Acoustic Reflex Testing
z z
z
Otoacoustic Emissions Testing Behavioral Audiometry – VRA, BOA, play audiometry Speech Recognition Testing
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
5 Other
1
Unknown
1
Kernicterus
Other
Family History
Intraventricular
Cerebral Palsy
2 CMV
8 3
0
Perinatal
12 12 11 11
10 Seizure
Other studies as needed
26
22 22
20
Syndromes
z
33
31 3
30
High Bili
– Inner ear malformations – Cochlear nerve integrity
47
Absent VIII
Radiologic Studies (MRI/CT)
40
Vent
z
Seizures Motor delays Visual problems Ear canal problems Otitis media
51
50
Ototoxic Meds
– – – – –
60
NICU
z
Normal
z
Medical History Ear Exam Etiology Other associated problems
Premature
z
Otoacoustic Emissions Testing Behavioral Audiometry – VRA, BOA, play audiometry Speech Recognition Testing
Why Comprehensive Medical Evaluation is Important UNC-Chapel Hill ANSD Children Medical Diagnosis N=112 81/112 (72%) have some positive history)
Otologic Examination z
Otologic Examination Auditory Brainstem Response (ABR) Acoustic Immittance Measures
Absent ABR:No Cochlear Microphonic Child with profound hearing loss
Estimated Audiogram from ABR
Abnormal ABR with Present Cochlear Microphonic
Abnormal ABR with Present Cochlear Microphonic Expanded time window
What is a Cochlear Microphonic (CM)?
What is a Cochlear Microphonic (CM)?
z z
z z
Receptor potential generated by the polarization and depolarization of cochlear hair cells Can be recorded in humans and experimental animals using: – Intra-tympanic or extra-tympanic electrocochleography (ECochG) – Surface recording electrodes
z
Most pediatric clinics in US routinely performing ABR but not ECochG
z z z z
Pre-neural response (occurs before Wave I in the ABR) Unlike the ABR, the CM shows a direct phase relationship to the acoustic wave form. When the polarity of the stimulus is changed there is a reversal of CM waveform Considered to have limited clinical use in p past;; renewed interest in diagnosis of ANSD CM can be recorded in normal ears, ears with “typical SNHL” and ears with ANSD Significance in ANSD is when CM is present when neural response is absent or markedly abnormal Amplitudes larger in patients with CNS problems (Santarelli et al 2006)
Variations in Amplitude and Duration of CM
Variation in CM
CM vs stimulus artifact
ABR Protocol for Evaluating CM z
Must have adequate recording conditions – Infant ready to sleep – Avoid electrodes positioned over transducer
CM vs. stimulus artifact
Single polarity clicks at 80 & 90dBnHL with rarefaction and condensation polarities z Must use insert earphones z No-sound run with sound tube disconnected or clamped to check for stimulus artifact z
Courtesy of John Grose
What’s Different? ANSD vs “typical” SNHL
Child Incorrectly Diagnosed with ANSD Poor vs Good Quality tracings
Not possible to obtain threshold estimates with ABR z Difficult to predict severity of disorder at time of diagnosis in infants using currently available tests z If infant is identified early with ANSD it may be several months before child’s detection thresholds can be adequately measured z
Lily sparks
ASSR z
z
ASSR responses can be obtained to high signal levels (>80dBHL) with ANSD but responses are elevated even in children who l t show later h normall behavioral b h i l audiograms di (Attias et al 2006, Rance et al 1998, Rance & Briggs, 2002) Therefore, ASSR cannot be used to determine thresholds in ANSD
Variable Presentations of ANSD
Variable Presentation of ANSD Case #1 Present CM and OAEs z
Dante
z z z
Variable Presentation of ANSD Case #1 Normal thresholds, present CM and OAEs
24 week preemie Intensive care nursery 4 months Ventilated 2 months ABR repeated at 18 months-no change Audiogram at 18 mos
Audiogram at 14 months
Variable Presentation of ANSD Case #2 Child with Profound Bilateral HL Present CM and OAEs
Audiogram at 18 months
Variable Presentation of ANSD #3 Child with “moderate loss” CM present, absent OAEs z
Makayla z z
Audio of moderate loss CM only Blake
Variable Presentation of ANSD Case #4 Large CM, present OAEs but distal waveforms Ethan
Behavioral Audiometry Case #4 VRA with insert earphones Age14 months
Is this normal hearing??
Child with Pelizaeus-Merzbacher Disease Wave I only (Case #5) z z z
z
z
Child with Pelizaeus-Merzbacher Disease Wave I only (Case #5)
Rare, progressive, degenerative CNS disorder Coordination, motor function and intellectual abilities deteriorate One of group of disorders called y p which affects the leukodystrophies growth of the myelin sheath Caused by a mutation in the gene that controls production of a myelin protein called proteolipid protein-1 (PLP1) X-linked, males affected, mothers are carriers of the PLP1 mutation
Variable Presentation of ANSD Case #6 Child with CHARGE Right: Moderate loss Left: Absent cochlear nerve
Variable Presentation of ANSD Case #6 Audiogram Age 21 months
z
Right ear:
z
Left ear:
– moderate mixed loss – Profound SNHL
Variable Presentation of ANSD Case #7 Child with bilateral deafness No VIIIth nerve on right
Variable Presentation of ANSD Case #7 Child with bilateral deafness No VIIIth nerve on right
sup
sup ant
ant
Right Ear
Right Ear
UNC Children with Auditory Neuropathy Characteristics and Cochlear Nerve Deficiency (small/absent VIIIth Nerve)
Left Ear
Absent Cochlear n.
Cochlear n.
z z z superior
superior Facial n.
Vestibular n. anterior Absent Cochlear n.
Facial n.
anterior
Vestibular n.
Cochlear n.
UNC Children with Auditory Neuropathy Characteristics and Available MRI (2009) N=140 z
35 (25%) Cochlear Nerve Deficiency (CND) in one or both ears – Unilateral (n=24; 69%) – Bilateral (n=11; 31%)
Left Ear
Retrospective review of 65 children with characteristics of ANSD 51/65 had MRI data available 9/51 (18%) had small or absent 8th nerves – Small (n=2); 4% – Absent (n=7); 14% Buchman, Roush,Teagle, Brown, Zdanski and Grose Ear and Hearing 2006 Aug 27(4): 399-408
UNC Children with Cochlear Nerve Deficiency (Small or Absent VIIIth nerve)
z
Radiographic studies not always clear or 100% accurate, difficult to know how to advise families – 5 ears in 4 kids were implanted – Have no electrical response at surgery – Stimulate but have no open set abilities
z
2008 numbers: 53 children with CND in program; approximately 2/3 have cochlear microphonic present
UNC Children with ANSD Radiologic Findings
Cochlear Nerve Deficiency at UNC z
Imaging characteristics – ~60% of ears have normal IAC (>3mm) – ~40% of ears have normal labyrinth – Many with normal CT scans
Probably need MRI in all kids!! Otology Neurotology 2006 Sep;27(6):793-801
Take Home z
Absent 8th Nerve – not uncommon – can result in auditory neuropathy phenotype – commonly has normal internal auditory canal (IAC) morphology p gy – commonly has normal labyrinth
z
z
Audiological, educational, and medical recommendations will be influenced by these findings e.g. CI or HA candidacy
Middle Ear Muscle Reflexes (MEMR)
z
Absent in majority of cases of ANSD (Berlin et al 2005; Sininger & Oba, 2001; Starr et al., 1996) Probe tone issues – 1000Hz probe tone for infants infants4 months
z
z
150+ children identified with ANSD – 66 % of ANSD children in our program have abnormal finding on MRI • White matter problems • Developmental brain abnormalities, e.g. Dandy Walker malformation • Cochlear nerve deficiency (~25%)
Recommended Audiologic Test Battery z z z
Caution should be exercised with MEMR in young infants as normative data with 1000Hz probe tone does not exist Suppression of OAEs with contralateral noise is abnormal with ANSD, however, this test not widely used clinically
Otoscopic Examination Auditory Brainstem Response (ABR) Acoustic Immittance Measures – Tympanometry – Acoustic Reflex Testing
Need MRI instead of CT in all kids – with profound hearing loss – with auditory neuropathy phenotype
z
z
z z
z
Otoacoustic Emissions Testing Behavioral Audiometry – VRA, BOA, play audiometry Speech Recognition Testing
Recommended Audiologic Test Battery z z z
Otoscopic Examination Auditory Brainstem Response (ABR) Acoustic Immittance Measures – Tympanometry – Acoustic Reflex Testing
z z
z
Otoacoustic Emissions Testing Behavioral Audiometry – VRA, BOA, play audiometry Speech Recognition Testing
Recommended Audiologic Test Battery
Otoacoustic Emissions (OAEs) Standard screening or diagnostic protocol using Transient-Evoked OAEs ((TEOAES)) or Distortion Product OAEs (DPOAEs) z May not be present initially z May disappear over time z Disappearance is independent of whether amplification has been used
z
z
z z
– Tympanometry – Acoustic Reflex Testing z z
z
z
z
z
Methods used vary according to the age and developmental level of the child If child premature, age is adjusted for prematurity and test choice depends on “adjusted age” If child has developmental delays, knowledge of child’s developmental age is helpful Parents can help when documentation unavailable
Behavioral Observation Audiometry(BOA) Limitations z z
Measures babies awareness and does not provide true threshold information High inter- and intra-subject variability – Unable to differentiate between mild and moderate hearing loss – Dependent on state, alertness, attention, etc
z z
May be helpful in providing some information to families in early months of life Should not be used to determine thresholds for purposes of hearing aid fitting
Otoacoustic Emissions Testing Behavioral Audiometry – VRA, BOA, play audiometry Speech Recognition Testing
Behavioral Audiometry: Guidelines for ANSD
Method Used Depends on Child’s Developmental Age z
Otoscopic Examination Auditory Brainstem Response (ABR) Acoustic Immittance Measures
z
z
Behavioral assessment of pure tone threshold using developmentally appropriate, conditioned test procedures such as VRA, COR For very young or developmentally-delayed infants, behavioral observation audiometry (BOA) may be used to observe infant’s reflexive response to sound but should not be interpreted as representing behavioral thresholds or minimum response levels
Visual Reinforcement Audiometry (VRA) z z
Best if infant is able to sit up and has good head control Normal hearing infants condition more easily than infants with hearing loss – Children with HL lack auditory experience
z
Children with severe to profound HL may need to condition using a vibratory signal from bone conduction transducer
ANSD Protocol for Infants: Audiological Assessment
z
One Example of Sound Room Configuration
Behavioral assessment with VRA beginning at 6-7 months th (d (developmental l t l age)) with ith goall off obtaining bt i i individual ear measures and bone conduction thresholds by 8-9 months of age – May be difficult (or impossible) with children who have additional developmental or medical challenges – Behavioral Observation Audiometry may be needed
VRA Six Month Old
A Better Method
Cortical Evoked Potentials (CAEPs) z
CAEPs not as reliant on timing as earlier evoked potentials and may be present when ABR is not
z
Unlike ABR must be completed in awake (but quiet infants)
z
CAEP may be useful tool for some difficult to test patients
– – –
z
Hood, 1998, Rapin and Gravel, 2003 Cone Wesson and Wunderlich, 2003) Pearce, W, Golding, M, and Dillon, H, Cortical Evoked Potentials in the Assessment of Auditory Neuropathy: Two Case Studies. Journal of the American Academy of Audiology, 2007, 18:380-39
Further CAEP research needed with normal infants and infants with SNHL and ANSD
Recommended Audiologic Test Battery z z z
Otoscopic Examination Auditory Brainstem Response (ABR) Acoustic Immittance Measures
z
z
z
z
MLNT/LNT words and phonemes (Kirk, et al, 1995) PB-k words and phonemes (Haskins, 1949) C-HINT sentences in quiet and noise conditions CASPA
z
Functional Assessment Tools :
z
Otoacoustic Emissions Testing Behavioral Audiometry – VRA, BOA, play audiometry Speech Recognition Testing
z
– IT-MAIS or MAIS(Zimmerman-Phillips, et al., 2000; Robbins, et al., 1991) – ELF
Diagnosis of ANSD: Summary z ABR – Must have good recording conditions – Use insert earphones – Avoid “alternating” g p polarity y clicks,, complete p rarefaction and condensation runs. – Complete “no sound run” to rule out stimulus artifact – Consequences of incorrect diagnosis are significant: • Incorrect diagnosis may lead to identifying a child with normal hearing or mild problem as deaf
Early Speech Perception Test battery (ESP) (Moog and Geers, 1990) – Standard – Low Verbal
z
– Tympanometry – Acoustic Reflex Testing z
Speech Perception Test Battery
Diagnosis of ANSD: Summary z
Behavioral Audiometry – Experience in evaluating infant and young children essential – Use established protocols such as those described by Judy Gravel and Judith Widen – Important p to remember that severity y of functional deficit may y not be related to level of pure tone thresholds – Accuracy of hearing aid fitting is only as good as our ability to determine the infant’s auditory capacity
z
Speech Recognition Testing – Critical to use developmentally appropriate measures as early as possible
Background Audiologic Management of ANSD in Infancy A Case Example
z z z z
Patricia Roush, AuD The University of North Carolina Chapel Hill
z
Twin; born at 25 weeks gestation Treated with phototherapy for jaundice Blood transfusion for anemia Treated with vancomycin and gentamicin for presumed sepsis Ventilated
First UNC Appointment: Audiology and ENT (6.5 months)
Background z z
z z z z
Failed AABR bilaterally in NICU Diagnostic ABR at outside facility at 4 months of age interpreted as no responses to clicks or tone bursts (500, 2000 or 4000Hz) at 90dBnHL T Tympanometry: t normall (1000Hz (1000H probe b ttone)) DPOAEs: absent Parents told child has profound bilateral hearing loss Recommendations made:
z
– Raised eyebrows to remote dropped on hardwood floor – Responds to some toys and animal noises – Dad whistles and child giggles
1. ENT referral for otologic evaluation and fitting of amplification. 2. In the future, he may be a candidate for cochlear implantation
First Appt. at UNC Audiology and ENT Age 6½ months (3 mos. adjusted age) z
Diagnostic ABR: – Single polarity clicks – No neural response with only a cochlear microphonic present – Tympanometry (1000Hz): within normal limits – DPOAEs: Absent
Discussion with family z z z z
z
z
Studies have shown that some children with ANSD benefit from conventional amplification while others, with similar thresholds, do not Further recommendations regarding audiological management will be made once additional information regarding child’s auditory status obtained
Results consistent with ANSD type hearing loss ABR does not allow us to estimate hearing thresholds nor predict degree of communication difficulty Children with ANSD exhibit thresholds ranging from WNL to profound Behavioral testing with VRA will be needed when child is developmentally able
Referrals
Discussion z
Parents report child showing some response to sound:
z
z
Referred to “Beginnings” to discuss available communication options and availability of services Early Intervention arranged after family indicated initial communication preference – Weekly home visits arranged with • Teacher of the Deaf • OT • PT Family provided with information re “HITCH UP” family support group
Genetics Consultation
ENT CONSULTATION Otologic examination z MRI scheduled z Referrals: z
– Genetics – Neurology – Opthalmology
Diagnosed with BeckwithWiedemann Syndrome – – – – – – – –
Rare Disorder (1:14,000 births) Large birth weight and length Macroglossia (large tongue) Hypoglycemia (low blood sugar in newborn period) Malocl ssion Maloclussion Omphalocele (abdominal wall closure problem) Ear grooves or pits Nevas Flammeus (strawberry mark commonly on forehead and eyelids) – Increased risk for neoplasms
z z z z z z
Child noted to have dysmorphic features Child suspected of having Beckwith-Wiedemann syndrome Chromosomal analysis confirmed diagnosis Alfa-fetoprotein to monitor for liver tumors Kidney ultrasound every three months Genetic testing for hearing loss
Behavioral Observation Audiometry (BOA) 7 1/2 months (4 mos adjusted age) z
z z z
Awareness responses noted to narrow band noise via bone conduction at moderately loud levels Tympanometry: normal DPOAEs: Partially present bilaterally Appt. scheduled for cortical auditory evoked potentials (CAEP)
• Most common: hepatoblastoma, Wilms tumor
Cortical Evoked Potentials (CAEP) 9 months (5 ½ mos adjusted age)
z z
Tympanometry normal OAEs attempted: Baby too active
Child Fell Asleep, ABR repeated 9 months (5 ½ mos adjusted age)
VRA in Sound Field 9 months (5 ½ mos adjusted age) z z
z
Child successfully conditioned for VRA Bone conduction responses similar to air conduction SDT: 55dBHL
VRA in Sound Field 11 months (7 ½ mos adjusted age) z
11/4/08 audio here z
z z z z
z
Hearing Aid Fitting Age 12 months (8 ½ months adjusted age)
Sound Field Audiogram Prior to Hearing Aid Fitting 12 months (8 ½ mos adjusted age) z z
z z
Parents comment that child more responsive to sound at home over o er past few fe weeks eeks Request hearing test prior to hearing aid fitting Completed in sound field so parents could hear level child responds to
z z z z
Unaided and Aided Detection Thresholds 13 months of age (9 ½ months adjusted age)
1/26/09
z z z
z
Unaided SDT: 55dBHL Aided SDT: 25dBHL Parents report increased awareness to sound in weeks following hearing aid fitting Mother emailed audiologist just prior to this visit to report child using consonant vowel babbling (da da da)
Binaural digital hearing instruments dispensed RECDs measured DSL targets g used Verified with simulated real ear measures Parents report increase in vocalizations following initiation of full-time hearing aid use
Next Steps z
z
Individual ear measures with air and bone conduction obtained Tympanometry: normal Acoustic reflexes absent DPOAEs absent SDT: 50dBHL (right) 55dBHL(left) Ear Impressions taken
z z z
Continued weekly intervention visits with teacher of the deaf SLP evaluation completed and SLP to also provide service in view of hearing loss and issues with macroglossia E l i b Evaluation by S Speech/language h/l pathologist h l i on UNC pediatric di i CI team if concerns re progress Team approach will be used to ensure that timely decisions are made regarding continued use of HA, referral for CI, or change in communication strategy
Key Points
Next Steps z
z z
Child to see pediatric audiologist every three months: – Monitor hearing thresholds and middle ear status – Evaluate hearing aid function – Make earmolds Speech perception measures to be completed as soon as child developmentally able Periodic return visits to ENT
z
z
z
z
Obtaining reliable behavioral thresholds for use in hearing aid fitting requires time, systematic approach and an experienced pediatric audiologist Also needed, SLPs and Teachers of the deaf who have extensive experience with children with “typical” sensorineural hearing loss Early, accurate diagnosis and initiation of habilitation provides opportunity to assess benefit at young age so child will be able to take advantage of critical period for language development Children with ANSD often have complex medical histories requiring appropriate medical consultations
ANSD: Questions z
Hearing Aids and Cochlear Implants
z
z z
ANSD: Questions z z z
z z
Will hearing aids be helpful for the short term or the long term? What constitutes an adequate trial period with amplification? How do we determine who will benefit from hearing aids or cochlear implants? What communication approach is best? Will alternative hearing aid processing strategies result in better performance?
What should we tell a family to expect following initial diagnosis of ANSD when infant is only a few weeks of age? Do all children who present with audiological findings of ANSD have the same disorder or to the same degree? Can treatment protocols be generalized or should they be individualized? Are there clinically available diagnostic tools that allow us to predict benefit from a particular technology?
Evidence Based Medicine: What it is and what it isn’t “Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research”
Sackett et al 1996 British Medical Journal David Sackett, Professor NHS Research and Development Centre for EBM Oxford
Evaluating Outcomes in ANSD: What Do We Need to Know?
Levels of Evidence 1.
2. 3 3. 4.
5. 6.
Systematic reviews and meta analyses of randomized controlled trials Randomized control trials Non randomized intervention studies Non-randomized Descriptive Studies (cross-sectional surveys, cohort studies, case control designs Case studies Expert opinion
z
z z z z z z
Early Management Recommendations z z z z
Who are the subjects in the Study? – –
Children or Adults? Cognitive impairments, other neuropathies or medical conditions?
When was the child fitted with a particular technology? For hearing aids: How was the adequacy of the fit determined? Were verification measures used? Was the technology used consistently? Was intervention provided? What type? How was the data collected and by whom? Is the information published in a peer reviewed journal?
More Recently Considered:
Use of low gain hearing aids or FM Low gain hearing aids in only one ear Avoidance of hearing aid use altogether Use of sign language or cued speech and avoidance of auditory verbal therapy
z
Use of linear amplification and avoidance of amplitude compression
z
Use of low frequency filtering or high frequency transposition
z
Temporal envelope enhancement
– Zeng et al 2006
– Zeng et al 2006 (Berlin, 1996; 1999, Berlin et al 2002, Hood 1998)
– Narne and Vanaja, 2008
Clinical Characteristics Reported z
ANSD: What does existing evidence tell us about clinical management?
z z z z
Pure tone thresholds ranging from normal to profound Disproportionately poor speech recognition abilities for the degree of hearing loss for some patients I Impaired i d ttemporall processing i Difficulty hearing in noise Hearing fluctuation
(Starr et al 1996, Zeng et al 1999, Kraus et al 2000, Rance et al; 2002; 2004; 2005, Zeng and Liu, 2006)
Rance et al 2005
Speech Perception Abilities in Children with ANSD In 2005 Rance and colleagues completed retrospective analysis of word recognition scores from previous published studies (41 ears): – Open-set word scores compared to norms provided by Yellin et al (1989) – PTA thresholds ranged from 18-80 dBHL – Open-set word scores in 18/41 (44%) were within expected range – 23/41 (56%) were borderline abnormal or significantly poorer than expected for adults with equivalent degrees of hearing loss
Dashed line: Minimum expected score for ears with SNHL
Speech Perception in Noise (Rance et al 2007)
Speech Perception in Noise (Rance et al 2007) Open and closed-set speech perception abilities assessed in 12 school-age children with ANSD and compared to 20 subjects with SNHL and 25 children with normal hearing. Results: z Closed set speech p understanding g was p poorer in presence of noise in the SNHL group than in the normal subjects z Closed set perception in noise not significantly different for ANSD children and SNHL counterparts but there was trend toward poorer performance in ANSD group z Open set speech perception was also similar in both the ANSD group and the SNHL groups with trend toward poorer performance in ANSD group
Conclusions: z
z z
Evidence regarding amplification in children with ANSD z
Evidence regarding amplification in children with ANSD
Deltenre et al 1999 (case report) – Reported case of premature infant with hyperbilirubinemia and respiratory distress – Child not amplified until age 4 when emissions disappeared – Significant aided benefit demonstrated at 6 years of age: (0% binaural unaided, 80% binaural aided)
z
Listening in presence of background noise was more difficult for children with ANSD than for children hild with ith normall h hearing i Results not consistent across subjects Some children with ANSD demonstrated reasonable speech perception abilities at low signal to noise ratios
Rance et al 1999 (n=10) – NAL prescriptive method used – 6/10 showed either open or closed set improvement in aided condition – 4/10 showed no measurable speech perception ability
z
z
Lee et al 2001 (n=2) – Both children had moderate to severe HL, aided early but showed poor open set speech perception abilities – Amplification strategy not reported Rance et al 2002 – Comparison of unaided and aided speech perception abilities in group of 15 children with AN/AD compared to group of children with typical SNHL – Results show ~50% of group showed significant open-set speech improvements; ~50% of group showed no open-set speech perception ability.
Evidence regarding amplification in children with ANSD z
Hearing Aids in Children with AN/AD: 50% Benefit from Hearing Aids
Rance et al 2002 – Comparison of unaided and aided speech perception abilities in group of 15 children with AN/AD compared to group of children with typical SNHL – Results show ~50% of group showed significant open-set speech improvements; ~50% of group showed no open-set speech perception ability.
Rance et al Ear and Hearing 2002
Open-set speech perception results (aided/unaided) for children with ANSD across studies Rance et al 2005
A: Deltenre et al 1999 B:Rance et al 1999 C:Lee et al 2001 D:Rance et al 2002
Speech Perception in Children with ANSD Managed with Hearing Aids or Cochlear Implants (Rance and Barker 2008) z
Evidence regarding amplification in children with ANSD z
Madden et al 2002 (n=22) – 16 used hearing aids and/or FM systems – 4 received CI – 4 did not require amplification (spontaneous improvement) – Aided speech recognition scores not reported – Hearing aid fitting strategy not reported
Speech Perception in Children with AN/AD Managed with Hearing Aids or Cochlear Implants (Rance and Barker 2008*)
20 children with AN/AD: – 10 with CI – 10 with HA
z
Results indicate speech perception findings of this aided AN/AD group were similar to those of implanted AN/AD group *Otology & Neurotology 29: 179-182, 2008
Speech Perception in Children with AN/AD Managed with Hearing Aids or Cochlear Implants (Rance and Barker 2008*)
Speech Perception in Children with AN/AD Managed with Hearing Aids or Cochlear Implants (Rance and Barker 2008*)
z
z
CNC phoneme score/average HL for AN/AD with bilateral HA Dashed line: – Minimum expected score for ears with SNHL (Yellin et al, 1989)
z
*Otology & Neurotology 29: 179-182, 2008
Summary z
z z
Summary z
Many children with ANSD have disproportionately poor speech recognition abilities for the degree of hearing loss while others perform like their peers with “typical” sensorineural hearing loss. Some children with ANSD have greater difficulty in noise while others do not Some children with ANSD appear to benefit from amplification and auditory based intervention while others require cochlear implantation and/or visual supplementation
z z z z
– Age at diagnosis and treatment – Appropriateness of device fitting – Consistency of use – Quality of intervention – Extent of family involvement – Cognitive abilities of child – Presence of other medical conditions
Evidence regarding outcomes from amplification is limited Few peer reviewed studies have been published Existing literature is based on small number of children Many anecdotal reports Only a few published studies document use of a prescription-based fitting strategy that ensures audibility of speech signals
Hearing Aid Fitting Protocol for Infants
Factors that may affect outcomes For all children benefit from a particular technology will depend on several factors including
8/10 AN/AD children show performance levels within the expected range for children with SNHL
z
Assessment – Behavioral thresholds estimated based on electrophysiologic measures
z
Prescriptive formula selected
z
Program Hearing instrument
– e.g. DSL, DSL NAL-NL1 NAL NL1 – Manufacturer’s software used z
Verification of Fitting – An alternative procedure to traditional probe microphone measures for use with infants and children is Real Ear to Coupler Difference measurement (RECD)
Verifying Audibility of Speech Spectrum Why Does it Matter?
Comparison of Manufacturer’s Fitting Algorithms Instruments from 5 manufacturers programmed using proprietary algorithm z Audiograms ranged from mild-profound z Used Average RECD for a 6-month old z
Seewald Drake and Moodie 2007
Sample Findings
Comparison of Manufacturer’s Fitting Algorithms
“Average” Speech Input
average inputs 130 120
Simulated real-ear hearing instrument performance was measured for: – – – –
110 output dB SPL
z
Soft speech Average speech Loud speech Output limiting
21 dB Difference
100
Series1
90
Series2 Series3
80
Series4 Series5
70 60 50 40 100
Seewald Drake and Moodie 2007
1000
10000
frequency
Seewald et al 2007
Sample Findings
Hearing Aid Fitting in Infants with ANSD: What’s different?
Output Limiting Levels mpo
z
160
133 dB SPL
150
output d dB SPL
140 130
Series1
120
Series2
110
Series3
100
Series4
90
Series5
80
103 dB SPL
70 60 100
1000
10000
frequency
Seewald et al 2007
Behavioral thresholds cannot be predicted from ABR or ASSR – Determination of hearing thresholds is delayed until infant p y able to p perform task ((6-9 months of age g for developmentally most infants) – Many children with ANSD are at risk for cognitive impairments resulting in a lengthier and more complicated process of threshold determination – This results in delays in hearing aid fitting and greater amount of time without adequate audibility of speech signal
Hearing Aid Fitting in Infants with ANSD: What’s Different? z
z
z
Speech Perception Test Battery z
Behavioral pure tone audiogram in ANSD does not have same prognostic value in prediction of aided benefit as with typical SNHL Considerable variability in presentation of ANSD even with similar initial test results
z
– Difficult to provide prognosis to families of newly diagnosed infants
z
Speech recognition testing not possible on children under two years of age making determination of benefit from amplification difficult (also true for young children with severe sensory loss)
z z z z z
z z z
IT-MAIS or MAIS (Parent Questionnaire) (Zimmerman-Phillips, et al., 2000; Robbins, et al., 1991) Early Speech Perception Test battery (ESP) (Moog and Geers, 1990) Standard Low Verbal PB-k words and phonemes (Haskins, 1949) MLNT/LNT words and phonemes (Kirk, et al, 1995) HINT sentences in quiet and noise conditions
Use recorded speech materials when child developmentally able to do so!
UNC Unilateral vs Bilateral ANSD N=140
University of North Carolina-Chapel Hill ANSD Study z z
z z z
140 infants and children with ANSD at UNC 10 year prospective study underway to determine characteristics of children with ANSD and benefit from assistive devices All patients evaluated by pediatric audiologist and otologist Neurology, genetics, ophthalmology consults recommended Many in study are very young and we are just beginning to be able to evaluate outcomes
UNC ANSD Children Assistive Listening Device N=140
(49)
CI + HA (8) HA (44) NAD (39)
31%
6%
Unilateral N=36 74%
Bilateral N=104
22 NAD unilateral normal hearing contralateral ear z 7 NAD normal hearing z 3 NAD no nerves z 6 NAD too young or too impaired z 1 NAD refused z
CI 35%
26%
UNC AN No Assistive Device N=39
Assistive Listening Devices N = 140
28%
Unilateral vs Bilateral AN N = 140
UNC AN Children with CI N=49
UNC AN Children with CI Open Set Performance N=25
CI in AN EAR 2 yrs of use) N=13 Limited Open Set (
