International perspectives on APDdiagnostics' Current trendsand status'

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International perspectives on APD-diagnostics.
Current trends and status. 
Milene Rogiers Drs. Hans Mülder Phonak
Switzerland
Expert Round Table March 20, 2007 Bergen, Norway

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Welcome !
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Why are WE here?

• At the heart of the world
• Phonaks nature
• As healthcare professionals and researchers
• From an international perspective
• The EduLink Story

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Why are YOU here?

• From a variety of disciplines
• Involved in diagnosis treatment of
  children/adults with APD
• Change in the intervention process
• Prepared for consensus
• Tools of the Trade

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Program outline

• Our Senses
• Children Adults with an Auditory Processing
  Disorder
• Definitions
• Screening
• Multidisciplinary team
• Diagnostics
• Behavioral traditional APD tests, Nottingham,
  UK Dave Moore team, LISN-S (NAL, Sharon
  Cameron)
• Electrophysiological AERP, ASSR, BioMap
  (Northwestern University, Chicago - Nina Kraus)
• Conclusions

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Our senses

Our senses connect us to the outside world. They
help us perceive and structure our surroundings

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Sense perception brain development

• Sense perception is energy which stimulates or
  activates nerve cells and iniates neural
  processes
• The brain develops "back-to-front" i.e. the
  sensory areas develop before the action areas
  (myelin membrane development)
• The brain needs input before it is able to
  develop ways to (re)act at the same time learns
  from our actions

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Sense perception sense integration

• Sense perception can be
• modal calculating information from one sense
  only
• polymodal calculating information from two or
  more senses simultaneously
• amodal coordinating information from different
  modalities, i.e. the ability to transfer
  experiences from one sense to another
• Sensory integration is a form of organization,
  where different sense elements are integrated
  into a whole
• A well-functioning sensory integration requires
  that one is able to direct attention towards
  specific sensory experiences while ignoring
  others

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Speech/Language communication development

• When developing speech/language and communication
  we combine information from

• What we hear with what we hear
• What we hear with what we see
• What we hear with what we feel (emotionally,
  intuitively)
• What we hear with what we feel (tactilly,
  proprioceptively)
• What we hear with what we smell
• What we hear with what we taste
• What we hear with what we do

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In discovering spoken language

• Infants are well equipped to begin processing the
  speech signal
• The nervous system begins with an overexuberance
  of connections that are paired down in the course
  of development
• Experience will tune the cells in the cortex
  through enhancement, attenuation, sharpening,
  broadening or realigning

(Jusczyk, 1997)
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Without a good supply of many accurate sense
impressions the nervous system will not develop
optimally, i.e. will not provide for optimal
integration and organization of sense impressions

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When something is wrong

• Hearing is one of our most important senses as it
  provides us access to spoken language and
  communication in general
• Normal functioning of the auditory sensory organs
  and the central auditory pathways is a
  prerequisite for the normal development of speech
  and language
• When our sense impressions are well-organized and
  integrated, our brain is able to use them to
  shape experience, behavior and learning and we
  are able to react to that which we receive
  through our senses with appropriate thoughts,
  emotions, actions and behaviors

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First indications

• Neonatal Hearing Screening
• A delay or disorder in speech, language (both
  spoken and written) communication, learning
  difficulties,
• Behavioral problems in the classroom/at home -
  coping with degraded, reduced, or distorted
  speech is fatiguing, so the children have a
  natural tendency to tune out, get distracted, and
  misbehave.
• A feeling the parents, teachers or other
  caregivers have

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To have children tune in again

• The motiviation for learning must come from
  within the child - Maria Montessori
• "Nine tenths of education is encouragement" -
  Anatole France
• "I never teach my pupils, I only attempt to
  provide the conditions in which they can learn
  Albert Einstein
• for long-term benefits

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For children, especially those with specific
deficits
Learning can be very challenging

• Because of factors within the child (child vs.
  adult, the specific nature of the disorder,)
• (Stollman, 2003 Bradlow, Kraus Hayes, 2003
  Musiek Chermak, 1997 Keller, 1998)
• Because of factors within the classroom
  (distance, background noise and reverberation)
• Factors related to learning

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Children Adults with an Auditory Processing
Disorder
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Some children in the classroom

• Difficulty understanding spoken language
• Misunderstanding messages
• Inconsistent or inappropriate responding
• Frequent requests for repetition, what, huh
• Taking longer to respond in oral communication
  situations
• Difficulty paying attention
• Being easily distracted
• Difficulty following complex oral directions
• Difficulty localizing sound
• Dificulty learning songs or nursery rhymes
• Poor musical and singing skills
• Associated reading, spelling, and learning
  problems
• Misbehaving in the classroom

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This may be because

• The child has a hearing loss
• The child has difficulties processing sound
• The child has difficulties paying attention
• The child has poor speech and language skills
• The child has difficulties understanding
  (cognitively) what is being taught
• The child is afraid when new material is being
  taught
• The child has some personal difficulties
• The child is having a bad day
• The child has specific difficulties making it
  hard for him/her to learn to read, write, do
  mathematics
• The child has behavioral issues
• The child has had no or the wrong kind of
  breakfast

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A hearing evaluation

• Children complaining of
• Poor understanding in background noise
• Confusing similar sounding words
• Unusually sensitive to sounds
• Trouble remembering and repeating orally
  presented information

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A turning point in the decision making process
"Hearing" related complaints
Standard assessment including- Hearing threshold
measurement- Middle-ear evaluation
Hearing thresholds are shifted
Hearing thresholds are "normal"
Comprehensive Management
Sorry
Comprehensive Management
Screening Diagnosis
Definition
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Hearing is our most important sense

• Hearing provides us access to spoken language and
  communication in general
• Hearing is the most efficient vehicle for
  learning

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Hearing is the base for learning

• Hearing is the most efficient vehicle for
  learning
• Educators capitalize on this and use
  auditory-oral instruction as the primary approach
  in the majority of classrooms
• This emphasis on listening can pose difficulties
  for children who cannot use this information
  successfully
• Information carried from the ear to the brain
  must be of high fidelity or the information
  available to the listener will be faulty

(Whitelaw, 2004)
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So

• Normal functioning of the auditory sensory organs
  and the central auditory pathways is a
  prerequisite for the normal development of speech
  and language

Degraded neural processing of speech sounds in
kids
Impaired perception of speech sounds
Impaired development of language skills
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Learning difficulties in the school

• A growing number of children exhibit learning
  difficulties
• Experts assume that many learning difficulties
  are at least partially caused by Auditory
  Processing Disorder (APD)
• Auditory processing disorders have been
  erroneously confused with other disorders
  (Specific Learning Disabilites, e.g. dyslexia,
  Attention Deficit/Hyperactivity Disorder)
• The effect of such learning difficulties usually
  become first apparent in classroom situations

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Classrooms are noisy places
Noise affects learning for all children

• Background noise

Reverberation
Distance
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Why are children at a greater disadvantage in a
noisy situation?

• Understanding speech means that we combine what
  we hear with what we know already
• Noise masks speech therefore we may hear less
  well than in quiet. And need to rely more on our
  language knowledge.
• A child does not have a completely developed
  auditory system
• Children children do not have the years of
  language and life experience that enable adults
  to fill in the gaps of missed information.

However, children bring a different listening to
a learning or communicative situation
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But for children with learning difficulties noise
affects learning even more

• Language-impaired children show significantly
  more speech understanding difficulties compared
  to their normal peers (Stollman, 2003)
• Children with a learning disability (LD) have
  poorer overall speech-in-noise perception than
  normal children and are more adversely affected
  by a decreasing SNR (Bradlow, Kraus Hayes,
  2003)
• Children with an Auditory Processing Disorder
  (APD) experience difficulties comprehending
  spoken language in competing speech or background
  noise (Musiek Chermak, 1997)
• Children with an Attention Deficit/Hyperactivity
  Disorder (ADHD) have difficulties following
  instructions (Keller, 1998)

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Processing speech involves
Cognition
Attention
Memory
ADHD
Other SP
CAP
(C)APD
PERCEPTION
Intelligence
Learning
Language
LD
SLI
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APD or Auditory Processing Disorder

Central auditory processing refers to the
efficiency and precision with which we handle
auditory information, primarily in the central
auditory nervous system (Katz, 2003)

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Or, in more detail
The pattern of a sentence creates a specific
meaning I want to drive to NY tomorrow(and not
fly)I want to drive to NY tomorrow(and not
today)
Knowing whether a sound comes from left /
right / middle
Hearing the difference between Bat / pat / hat
/ fat
How the sounds are organized in a word
determines its meaning Lemonade / Menolade Tsar
/ Star Reserve / Reverse
ASHA (1996) defines APD as an observed
deficiency in

• Sound localization and lateralization
• Discrimination
• Pattern recognition
• Temporal aspects of listening
• Speech understanding in noise

American Speech-Language Hearing Association
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How often/Why does APD occur?

• 3-5 of all children (Musiek, 1997)
• 2 times more boys than girls
• Possible causes
• Developmental / hereditary
• Incorrect configuration of neurons and synapses
• Delay in auditory development / maturation of
  the system
• Neurological disorders, diseases, trauma, tumor,
  neurodegenerative disorders,

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ADHD or Attention Deficit/Hyperactivity Disorder

• These children may know what to do, but arent
  always able to complete their tasks because they
  are
• unable to focus
• impulsive
• easily distracted
• Children with ADHD often cannot sit still or pay
  attention in schools

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How often/Why does ADHD occur?

• 4-12 of all children
• Twice as many boys as girls
• Possible causes
• Developmental / hereditary
• Brain areas for control of attention show lower
  level of activity
• Prenatal use of dangerous substance
• Toxins in the environment

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A specific Learning Disability or LD?

• Language deficits are the fundamental
  ingredient
• The three Ds
• Dyslexia - reading
• Dysorthographia - writing
• Dyscalculia - arithmetics

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For example
Goldstein, S., Mather N., Learning Disabilities,
Brooks Publishing, 2001
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How often/Why does LD occur?

• 5-10 of all children
• Twice as much boys as girls
• Possible causes
• Too many possibilities to be sure
• Diverse and complex
• More recent evidence shows that LDs do not stem
  from a single, specific area, but from
  difficulties in bringing together information
  from various brain regions.
• Leading theory subtle disturbances in brain
  structures and functions

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Learning difficulties in children can result from
ADHD 4-12 of all children
APD 3-5 of all children
LD 5-10 of all children
Of all children with learning difficulties, in
more than 50 APD will play a significant role
(Rosenkötter, 2003)
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Learning difficulties in children can result from
ADHD 4-12 of all children
APD 3-5 of all children
LD 5-10 of all children

• Co-morbidity
• Overlap
• Causality
• Other

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How are these children managed?
Comprehensive management by a multidisciplinary
team

• Direct remediation therapy
• Compensatory strategies
• Environmental modifications

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Definition of (C)AP (C)APD
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Definition of (C)AP (C)APD (Katz, 1992)

• (C)AP is what we do with what we hear
• (C)APD is when something goes wrong with what we
  do with what we hear

Wayne Wilson, 2006
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Thinking of (C)APD

• The dictionary definition of
• Central
• Auditory
• Processing
• Disorder

Wayne Wilson, 2006
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(Central)

• Part of the central nervous system
• As versus peripheral

Wayne Wilson, 2006
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Auditory

• Relating to hearing
• relating to the hearing organs, or the process of
  hearing
• Encata Dictionary
• As versus visual, kinesthetic, etc.

Wayne Wilson, 2006
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Processing

• Process
• a series of actions directed towards a particular
  aim
• Processing
• to treat or prepare something in a series of
  steps or actions
• Encata Dictionary

Wayne Wilson, 2006
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Processing versus Perception

• Percept
• The object perceived the mental image of an
  object in space percieved by the senses
• Perception
• The conscious mental registration of a sensory
  stimulus
• Dorlands Pocket Medical Dictionary (1995)

• Process
• a series of actions directed towards a particular
  aim
• Processing
• to treat or prepare something in a series of
  steps or actions
• Encata Dictionary

Wayne Wilson, 2006
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The concept of processing as a pre-requisite to
perception

• Sufficient processing of sound by the auditory
  system is needed if perception is to occur
• But sufficient processing of sound by the
  auditory system DOES NOT GUARANTEE perception
• True perception of sound requires more than just
  auditory processing

Wayne Wilson, 2006
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Disorder

• Disorder
• a derangement or abnormality of function a
  morbid physical or mental state
• Dorlands Pocket Medical Dictionary (1995)

Wayne Wilson, 2006
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Disorder versus Difficulty

• Disorder
• a derangement or abnormality of function a
  morbid physical or mental state
• Dorlands Pocket Medical Dictionary (1995)

• Difficulty
• the quality of being hard to do, understand, or
  deal with
• Encata Dictionary

Wayne Wilson, 2006
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Therefore a dictionary definition of
(Central)
Auditory
Processing
Disorder
could be
(CANS)
Disorder
Processing
Auditory
Wayne Wilson, 2006
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ASHA (2005)

• Broadly defined (C)AP as referring to
• the efficiency and effectiveness by which the
  central nervous system (CNS) utilizes auditory
  information (p. 2)

Wayne Wilson, 2006
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ASHA (2005)

• Narrowly defined (C)AP as referring to
• the perceptual processing of auditory
  information in the CNS and the neurobiologic
  activity that underlies that processing and gives
  rise to electrophysiologic auditory potentials
  (p. 2)

Wayne Wilson, 2006
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ASHA (2005)

• Stated that (C)AP includes
• the auditory mechanisms that underlie the
  following abilities or skills
• - sound localization and lateralization
• - auditory discrimination
• - auditory pattern recognition
• - temporal aspects of audition, including
  temporal integration, temporal discrimination
  (e.g. temporal gap detection)
• - temporal ordering
• - temporal masking
• - auditory performance in competing acoustic
  signals (including dichotic listening)
• - auditory performance with degraded acoustic
  signals
• (ASHA, 1996 Bellis, 2003 Chermak Musiek, 1997)

Wayne Wilson, 2006
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ASHA (2005)

• Defined (C)APD as referring to
• difficulties in the perceptual processing of
  auditory information in the CNS as demonstrated
  by poor performance in one or more of the above
  skills (p. 2)

Wayne Wilson, 2006
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ASHA (2005)

• Defined the nature of (C)APD as

• (C)APD is a deficit in neural processing of
  auditory stimuli that is not due to higher order
  language, cognitive, or related factors
• However, (C)APD may lead to be or be associated
  with difficulties in higher order language,
  learning, and communication functions
• Although (C)APD may coexist with other disorders
  (e.g. ADHD, LI, LD), it is not the result of
  these disorders
• For example, children with Autism or ADHD

Wayne Wilson, 2006
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Auditory Processing Disorder
Definition British Society of Audiology
(2004) a hearing disorder resulting from
impaired brain function and characterised by poor
recognition, discrimination, separation,
grouping, localisation, or ordering of non-speech
sounds

• There are currently no validated UK tests to
  diagnose auditory processing disorder
• No UK epidemiological data to estimate prevalence
  of APD though estimates vary between 2-3 some
  are reportedly as high as 10

Melanie Ferguson, 2006 With the approval of David
Moore
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Multidisciplinary team
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Multidisciplinary team (Bellis, 2003)

• Audiologist (Coordinator)
• Speech-Language Pathologist
• Educator
• Psychologist
• Social worker
• Parents
• Physician

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Screening DiagnosticsIntervention
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Holistic approach

• Bellis (2002) look at weakness strengths
• The child as a whole body, mind soul
• Considering mirror neurons the child and beyond
  including the childs immediate surroundings
  (family, school,)

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Screening
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Screening

• (versus diagnostics)

• Mass screening for early identification. No such
  tests exist. NOT RECOMMENDED
• Usually referrals from parents and/or teachers
  observation of the behavior of the child
• Parent/Teacher questionnaires checklists
  (CHAPS, Fishers, SIFTER, LIFE, CHILD)
• Audiological screening tests
• Non-audiological screening tests

Wayne Wilson, 2006
63
Audiological screening tests

• (versus diagnostics)

• Measures of peripheral auditory function should
  be obtained first
• puretone audiometry
• speech audiometry
• acoustic immitance measurements (incl. ipsi and
  contra reflexes)
• OAEs
• Screening measures of central auditory function
  should be obtained second

Wayne Wilson, 2006
64
Non-audiological screening tests

• (versus diagnostics)

• Measures of cognition, learning, speech and
  language should be obtained first
• NEVER (C)APD testing as stand-alone !!!

Wayne Wilson, 2006 Bellis, 2002
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Pass/refer

• Only recommend a diagnostic (C)APD assessment is
  screening assessments show
• an emphasis on deficits in the auditory behaviors
• a scatter in speech-language and
  psycho-educational tests with the weaknesses
  being in auditory-dependent or possibly auditory
  subservient areas e.g. phonological awareness and
  decoding, comprehension of lecture-based academic
  information, reading rate and accuracy, verbal IQ
  lower than performance IQ, etc

Wayne Wilson, 2006 Bellis, 2002
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Diagnostics
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Considerations

• For differential diagnostics as pre-requisite
  for customized intervention
• Advantages/disadvantages of behavioral vs
  electrophysiological tests
• Age of identification
• Professions
• Standardization
• Test set-up requirements
• Governemental requirements

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ASHA (2005)US
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Test principles (ASHA, 2005)

• Audiologist knowledge, training, skills
• Motivated by referral complaint, not test driven
• Only tests with good reliability, validity, high
  sensitivity, specificity and efficiency
• Test battery includes measures that examine
  different central processes
• Both verbal and non-verbal stimuli to evaluate
  different aspects of auditory processing and
  different levels of the ANS (native language!)
• Sensitive to attributes of the individual
  (language development, motivational level,
  fatigability, mental age, cultural aspects,
  native language,
• Careful consideration of normative information
  and background, test set-up as specified
• Careful age gt 7 years
• Duration of the test session adapted to the
  individual needs
• Multidisciplinary team
• Auditory diagnostic tets 1 part only of a
  multifaceted evaluation

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Types of (C)APD tests (ASHA, 2005)

• Auditory discrimination test
• Auditory temporal processing patterning test
• Dichotic speech test
• Monaural low-redundancy speech test
• Binaural interaction test
• Electroacoustic meaures (OAEs, SR threshold
  decay)
• Electrophysiological recordings (ABR,
  middle-latency, 40 kHz response, steady state
  evoked potentials, frequency following response,
  cortical event related potentials, mismatch
  negativity, topographical mapping,)

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Diagnostic assessment (Audiologist)Traditional
(C)APD tests

• 1 dichotic task involving binaural seperation
• 1 dichotic task involving binaural integration
• 1 temporal patterning (ordering) test
• 1 monaural low-redundancy speech test
• 1 temporal gap detection test
• 1 binaural interaction test
• 1 auditory discrimination test
• physiological measures
• Bellis (2003) provides all protocols and her
  clinics normative data

Wayne Wilson, 2006
72
Diagnosis decision criteria

• Diagnosis of (C)APD requires performance deficits
  on the order of at least two standard deviations
  below the mean on two or more tests in the
  battery (Chermak Musiek, 1997)
• Inconsistencies across tests signal the presence
  of a non-auditory confounds rather than a (C)APD
• If poor performance is observed on only one test,
  the audiologist should withhold a diagnosis of
  (C)APD unless the clients performance falls at
  least 3 SDs below the mean or when the finding is
  accompanied by significant functional difficulty
  in auditory behaviors reliant on the process
  assessed. The failed test should also be
  re-administered as well as another similar test
  that assesses the same process (to confirm the
  initial findings)

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David Moore TeamMRC Nottingham, UK
The following slides are from Melanie Ferguson,
with approval of David Moore For additional
information www.ihr.mrc.ac.uk/research/projects/a
pd/
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IHR Childrens Auditory Processing Evaluation

• Aim
• To develop a short clinical test battery to
  diagnose APD in primary school aged children in
  the UK
• Population-based approach
• Small sample, many tests
• Large sample, few tests

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What have we done?
2005
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Test battery
Auditory processing tests
Cognitive tests
Audiology and speech tests

• Normally- hearing children 6-11 y.o.
• n75

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Cognitive Tests General cognitive
ability Phonological awareness Language Reading
Memory
Cognitive tests
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Audiology Pure tone audiometry Otoadmittance
tests TEOAEs contra. suppn Speech Sentence
(language) VCV nonsense (speech) in noise and in
quiet
Audiology and speech tests
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Which AP tests?

• Reliability
• Within-session reliability
• Most tests moderate to high (r 0.6-0.89)
• Across-session reliability
• Half tests moderate (r 0.45-0.67)
• Half tests poor (r lt0.3)
• No practice effects

Frequency discrimination Frequency
resolution Backward masking
Developmental effects
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What are we doing?
2006
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Tests of higher order processing(normally-hearing
children)

• Binaural interaction dynamic masking level
  difference (Gatehouse and Ackeroyd)
• Spatial hearing Listening in Spatialised Noise
  (LISN-S) (Cameron and Dillon)
• Visual (attention)
• Ordering (loosely based on Tallal repetition
  test)
• Sentence and nonsense words modulated ICRA-5
  noise

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Where to next?
2007
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Multi-centre population study

• n approx. 1600 children 6-11 yo
• Stratified by age, sex and occupational group

Nottingham Exeter Glasgow Cardiff
1 hour test battery ?AP tests, speech, cognitive
test

• normalise auditory processing data
• profiles of APD
• prevalence of APD

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LISN-S
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BioMap
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Conclusions

• Auditory Processing Disorder similarity issues
• Definition influences tests needed/used in
  diagnostics
• Diagnostics implies differentiation and is
  pre-requisite for intervention
• Many types of tests behavioral, electroacoustic,
  electrophysiological
• Language language-dependent tests, non-native
  speakers

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Thank you for your attention!