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Differentiating Auditory Processing Disorders from Auditory Neuropathy Spectrum Disorders in the Deaf-Blind Population

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Differentiating Auditory Processing Disorders from Auditory Neuropathy Spectrum Disorders in the Deaf-Blind Population Charles I. Berlin Ph.D. Clinical Professor of ... – PowerPoint PPT presentation

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Title: Differentiating Auditory Processing Disorders from Auditory Neuropathy Spectrum Disorders in the Deaf-Blind Population


1
Differentiating Auditory Processing Disorders
from Auditory Neuropathy Spectrum Disorders in
the Deaf-Blind Population
  • Charles I. Berlin Ph.D.
  • Clinical Professor of Otolaryngology Head and
    Neck Surgery and CSD at University of South
    Florida, and Clinical Coordinator All Children's
    Hospital Center for Auditory Neuropathy

2
What does it sound like to have
  • Peripheral Hearing loss vs. Auditory Neuropathy
    vs. CAPD
  • Digression into underlying auditory physiology
    beginning with some of the relationships of
    speech to hearing.
  • Demonstrations and videos.

3
Auditory Neuropathy Spectrum Disorders vs. CAPD
  • Very easy to differentiate with the use of
    tympanometry, middle ear muscle reflexes,
    otoacoustic emissions and, if needed, an Auditory
    Brainstem Response.

4
How do we test for them
  • Peripheral hearing loss, stemming from damage to
    the outer hair cells and cochlea.
  • (Central) Auditory Processing Disorders
  • Auditory neuropathy spectrum disorders
  • Tympanometry
  • Middle Ear Muscle Reflexes
  • Otoacoustic Emissions
  • Auditory Brainstem response

5
Tympanometry Alone
http//vimeo.com/ncdb/tympanometry-alone
Copy the above URL into your browser view
video. You must be connected to the Internet to
view the video.
6
Tympanometry (3x) and Middle Ear Muscle Reflexes
http//vimeo.com/ncdb/tympanometry-reflexes
Copy the above URL into your browser view
video. You must be connected to the Internet to
view the video.
7
Otoacoustic Emissions by Distortion Products
http//vimeo.com/ncdb/otoacoustic-emissions
Copy the above URL into your browser view
video. You must be connected to the Internet to
view the video.
8
Auditory Brainstem Response with clicks being
presented rapidly to the ear.
http//vimeo.com/ncdb/abr-to-clicks
Copy the above URL into your browser view
video. You must be connected to the Internet to
view the video.
9
Behavioral Observation by localization
http//vimeo.com/ncdb/behavorial-audiometry
Copy the above URL into your browser view
video. You must be connected to the Internet to
view the video.
10
Auditory Processing Disorders
  • Thierry Morlet, Ph.D.

11
Auditory Processing
  • How our brain processes the sounds we hear
  • Central auditory processing includes auditory
    mechanisms that underlie the following abilities
  • Sound localization/lateralization
  • Auditory discrimination
  • Auditory pattern recognition
  • Temporal aspects of audition
  • Auditory performance with competing signals
  • Auditory performance with degraded acoustic signal

12
Auditory Processing and Language
  • The development of language is dependent on the
    identification of sounds (including assessment of
    factors such as intensity, frequency and timing).
    This capacity enables the detection of phonemes
    and is the basis of auditory language reception
    and utilization.
  • Production of a sound mirrors the perception
    individuals have of the sound.
  • Central auditory processing manifests differently
    in every individual child.

13
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 APD are not known, and in all
    likelihood, APD as broadly defined represents a
    family of auditory processing deficits stemming
    from multiple causes.

14
Auditory Processing Disorders
  • Approximately 5 of school-aged children have
    some type of APD.
  • APD can impair a childs speech and language
    development, leading to listening and learning
    deficits.
  • Its diagnosis is complex and often is not made
    until learning deficits are well established
    impairing the childs development for several
    years.
  • The lack of knowledge regarding the etiology of
    APD makes its management unpredictable.

15
Auditory Processes that are affected
  • Awareness/ detection
  • Discrimination
  • Recognition
  • Figure Ground
  • Synthesis
  • Memory and sequential memory
  • Temporal resolution
  • Closure
  • Binaural separation/ integration
  • Attention
  • Auditory processing disorders are difficult to
    differentially diagnose apart from other learning
    disorders

16
Indicators of APD Disorders
  • Poor reading spelling
  • Low class participation
  • Withdrawn
  • Responds inappropriately
  • Poor receptive/expressive language
  • Difficulty understanding in poor acoustical
    settings
  • Attention problems

17
Risk Factors for APD
  • Neurologic dysfunction and disorders, e.g.,
  • neonatal risk factors (e.g., asphyxia, CMV)
  • head injury
  • seizure disorders
  • Chronic otitis media in preschool years
  • Academic underachievement or failure
  • Family history of academic underachievement
  • Co-existing disorder (s)

18
Co-existing Disorders The Same Brain
  • APDs
  • Specific language impairment (SLI)
  • Learning disabilities (LDs)
  • Reading disorders (dyslexia)
  • AD/HD
  • Emotional psychological disorders
  • Developmental delay
  • Other neurologic deficits
  • and Autism spectrum disorders

19
Neurologic Bases
20
APD
  • Understanding the source of a communication
    problem
  • Peripheral or central or both?
  • Physiologic versus behavioral methods
  • Application of cortical auditory evoked
    potentials
  • Documenting effect of training
  • Neural plasticity
  • Importance of tests battery and cross-check

21
Diagnosis of APD
  • Ideal minimal test battery
  • Electrophysiological measures
  • Immittance measures Tympanometry AND acoustic
    reflexes
  • Otoacoustic Emissions
  • Auditory evoked potentials
  • Behavioral measures
  • Pure tone speech audiometry in quiet and in
    noise
  • Assessing all of the individual processes of CAP

22
Auditory Physiologic Responses
  • Middle ear muscle reflexes
  • Otoacoustic Emissions (OAE)
  • Suppression of OAEs
  • Auditory Brainstem Response (ABR)
  • Eight nerve and brainstem
  • Middle Latency Response
  • Thalamo-cortical pathways
  • Cortical Responses
  • N1-P2 or vertex response
  • P300 response
  • Mistmatch negativity (MMN)

23
Auditory Neuropathy Spectrum Disorder or APD?
  • Auditory Neuropathy/Dys-Synchrony
  • Synchrony disorder, possible pre-neural site
  • Cochlear implants a management option
  • ABR, MEMR absent
  • Central APD
  • More diffuse in nature, peripheral synchrony
    usually within normal limit
  • Cochlear implant not useful
  • ABR, MEMR usually normal

24
APD and the Peripheral Auditory System
  • One possible cause of APD that has received
    attention recently is a disruption of processes
    in the peripheral auditory system this led to
    the reclassification of central auditory
    processing disorder as APD.
  • Studies of peripheral auditory afferent pathways
    using click auditory brainstem responses in
    children with APD have been inconclusive.
  • ABRs are present in children with APD.
  • However, recent measures of speech auditory
    brainstem response show that the response in
    children with APD is delayed and less precisely
    timed, suggesting that their difficulties in
    higher-level language processes may have roots in
    the basic representation of sound as low as the
    brainstem.

25
Middle Latency Responses
  • The middle latency responses arises from the
    upper brainstem and primary auditory projection
    areas.
  • MLR latencies decrease with age in normal
    children.
  • Changes can be seen well into childhood, and
    adult characteristics are not reached until 10-12
    years of age.
  • Longer MLR latencies in children with APD.

26
Auditory Evoked Related Potentials
  • AERPs provide an objective means of evaluating
    how the auditory cortex codes acoustico-phonetic
    cues crucial to speech and language processing
    with high temporal precision, including in
    presence of background noise.
  • AEPRs also inform about hemispheric
    lateralization.
  • Can be obtained regardless of whether the subject
    is attending to the stimuli or not which excludes
    the factor attention as a possible confounding
    factor (MMN).
  • The obligatory AERP consist of a series of vertex
    positive and negative peaks (P1, N1, P2 and N2).
  • Mature by mid teens
  • Can be recorded at younger ages
  • Neural Plasticity

From Wunderlich and Cone-Wesson, 2006
27
Asymmetries of the Auditory System
  • In normally hearing individuals, anatomical and
    functional observations from the cochlea up to
    the cortex are in favor of a right ear advantage
    (REA), a feature hypothetically linked to the
    fact that in almost all right handed and most
    left handed people, speech is processed
    predominantly in the left cerebral hemisphere.
  • Both afferent and efferent auditory pathways show
    asymmetrical features which suggests that
    competing signals from both ears are processed
    with a REA which enables the left hemisphere to
    process speech appropriately in difficult
    listening situations.
  • Stimuli with complex speech-like acoustic
    properties, including rapid spectrotemporal
    changes, yield greater activation in auditory
    cortex over the left hemisphere, regardless of
    whether right ear, left ear, or binaural
    stimulation is used.
  • The left hemisphere is specialized from birth for
    processing specific properties of speech and
    children exhibit the right ear advantage as early
    as the first year of life.

28
Asymmetries in children with APD
  • Evidence of abnormalities in the cortical
    development of auditory areas in children with
    APD
  • Abnormal asymmetries in the perisylvian region of
    the temporal lobe with an absence of left
    hemispheric advantage for this region.
  • Abnormalities in auditory hemispheric
    specialization, in right ear advantage and in
    AERP have been reported in children with APD.
  • Abnormal functioning of the left temporal cortex
    in some children with APD suggest that the
    functional specialization of both hemispheres is
    impaired in these children and that damage to the
    left hemisphere disrupts mechanisms critical for
    processing brief, rapidly changing acoustic cues.
  • Enlarged AERP response in the right hemisphere
    could indicate differences in hemispheric
    lateralization in that children with APD may rely
    more on right hemisphere function when processing
    language, which has been suggested to serve as a
    compensation for improper functioning of the left
    hemisphere language areas.

29
P300
  • Dependent on focusing of attention and subtle
    cognitive processes
  • Can use speech stimuli of various types
    (discrimination, semantic distinctions, etc)
  • Can probe psychophysical function (discrimination
    of two tones, etc)
  • P300 is present in children with APDs but with
    longer latencies and reduced amplitudes as
    compared to controls.

30
Mismatch Negativity
  • Neuronal response to minimal changes in acoustic
    stimuli
  • Objective
  • Passively elicited
  • Pitch, phonemes, temporal and spectral cues, etc
  • Diminished mismatch negativity (MMN) responses to
    rapidly changing stimuli in APD compared to
    normal children.

31
Efferent Auditory Pathways
32
Efferent Auditory Pathways
  • The medial olivocochlear system (MOCS) innervates
    the outer hair cells. This implies that the
    acoustic signal stimulating the cochlea can be
    modified before it reaches the brain.
  • The MOCS constitutes one of the physiological
    mechanisms underlying perceptual intensity
    discrimination in noise.
  • In normally hearing adults and children,
    activation of the MOCS improves speech-in-noise
    intelligibility.
  • The MOCS is active after term birth in humans.
    Its development is asymmetrical (in favor of the
    RE).

33
MOCS in Children with APD
  • Recent studies showed some evidence of an
    impairment of MOCS function in children with APD
    or language impairment with a decrease in TEOAE
    suppression despite normal hearing thresholds.
  • MOCS dysfunction has been shown in subjects with
    other deficits such as in autistic children and
    children with selective mutism.
  • Several studies showed an inverted pattern of
    MOCS asymmetry in children with specific language
    impairment and in children with selective mutism
    versus controls.
  • Auditory training can change MOCS asymmetry in
    children with specific language impairment
    leading to bigger suppression in the right ear
    than the left ear after training. This finding
    was observed as well in children with reading
    disabilities following audiovisual training.

34
Efferent Suppression in Normal Children
35
Suppression in Children with APD
36
Management of APD
  • Requires interdisciplinary approach
  • Should
  • Be extensive
  • Maximize opportunities for generalization
  • Reduce functional deficits
  • Include salient reinforcement to induce learning
  • Comprehensive intervention management should
    include
  • Direct skill remediation by SLP
  • Compensatory strategies by Aud
  • Environmental changes by teachers and/or parents

37
Intensive Computer-Based Programs for
Development of Auditory Processing Skills
  • Cognitive Concepts
  • Earobics
  • cogcon.com
  • Scientific Learning
  • FastForword (FFW)
  • scilearning.com
  • Lindamood Bell Learning Processes
  • LIPPS and Seeing Stars
  • Lindamoodbell.com

38
Intervention
39
Language Skills Pre and Post Fast Forword
40
Efferent Suppression Pre-FFW
41
Efferent Suppression Post-FFW
42
MLRs Pre and Post FFW
43
MLRs Pre and Post FFW
44
Conclusions
  • Like children with ANSD, children with APD have
    the basic difficulty of understanding any speech
    signal presented under less than optimal
    conditions.
  • We are still not sure what causes APD. Diagnosis
    is complicated and usually not realized in a
    timely fashion. Management of APD is difficult
    and success is not guaranteed.
  • Despite sharing many common outcomes with ANSD,
    APD can easily be distinguished from ANSD.
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