(C)APD and Aging

Question 1

Can CAPD show up in older listeners?

Answer 1

Yes
(C)APD is often present in childhood, but adults may develop it from having certain diseases, getting a head injury, or just growing older
It is well documented that older adults have difficulty with speech perception especially in adverse listening environments even with fairly-good hearing sensitivity

Question 2

What is APD in its simplest form?

Answer 2

A hearing issue that makes it hard to understand what people are saying

Question 3

What are the signs of CAPD for children are seen in adults?

Answer 3

Difficulties with sound localization
Poorer auditory discrimination and pattern recognition
Difficulty with temporal aspects of audition
Decrements in auditory performance for degraded and competing acoustic stimuli
Difficulty with binaural integration
*These difficulties, in turn, can and do affect the speech perception abilities of older adults especially in noise

Question 4

In most instances, will CAPD in older adults occur in the absence of neuropathological conditions?

Answer 4

Yes

Question 5

What are the prevalence rates for CAPD in adults?

Answer 5

Varied due to differences in define and diagnosing CAPD, the degree to which peripheral HL and cognitive factors are controlled, and whether the sample was clinical or population based

Question 6

Does CAPD prevalence increase with age?

Answer 6

Yes
Secondary CAPD (secondary to age and hearing loss)
By some estimates, overall prevalence is ~ 15% to 25%
In adults > 60 years in the clinical population, prevalence may increase to as much as 70%
In adults > 80 years in the clinical population, prevalence may increase to as much as 95% and ~72% in the nonclinical population

Question 7

What is central presbycusis?

Answer 7

A hypothesis that hearing loss in elderly may have a central component such as attention, memory, and cognition
Age-related change in the auditory portions of the CNS negatively impacting auditory perception, speech-communication performance, or both
Task force was created to investigate this

Question 8

Why is attributing auditory-perception or speech-communication difficulties to central presbycusis difficult to do?

Answer 8

Many older adults have co-existing peripheral (sensorineural) hearing loss, age-related cognitive changes, or both

Question 9

What were the conclusions of the task force for central presbycusis?

Answer 9

Insufficient evidence to confirm the existence of central presbycusis as an isolated entity
On the other hand, recent evidence has been accumulating in support of the existence of central presbycusis as a multifactorial condition that involves age- and/or disease-related changes in the auditory system and in the brain
More research is needed

Question 10

What are the three hypotheses that have been offered for the decreased speech perception abilities in older listeners?

Answer 10

Peripheral factors
Cognitive factors
Central auditory factors

Question 11

What is the single most important factor affecting speech perception abilities in the elderly?

Answer 11

Peripheral sensitivity and signal audibility rather than aging alone
*Researchers therefore caution that even a mild HL may affect performance on CAPD tests for both adults and children

Question 12

Can both low and high frequency loss contribute to auditory impairment?

Answer 12

Yes
Sensory hearing loss can lead to alterations upstream; central effects that go well beyond the cochlea

Question 13

Is there significant evidence to support changes in the cochlear nucleus extending all the way up to the auditory cortex?

Answer 13

Yes
As a secondary response to a peripheral HL
In animal studies, high frequency SNHL shows
Decreased audibility of certain spectral components
Disruption in the tonotopic organization

Question 14

Is cross-modal plasticity or re-organization a form of cortical compensation?

Answer 14

Yes
It is observed in deafness and hearing loss
The auditory cortex is repurposed or taken over by visual and somatosensory modalities

Question 15

What can the change in tonotopic organization lead to?

Answer 15

Degraded decoding of high frequency spectral cues in the speech signal
This re-organization may also result in degrading of temporal encoding of acoustic signals (lead to significant disruption in auditory processes that rely on spectral and temporal encoding, such as speech)

Question 16

Does the brainstem and thalamic central auditory structures also exhibit trans-synaptic degeneration as a result of cochlear pathology?

Answer 16

Yes

Question 17

Has animal research shown a direct relationship between noise exposure and decoupling of auditory nerve fibers from hair cells; synaptopathy?

Answer 17

Yes
The primary finding is that the synaptic count is negatively correlated with amount of noise exposure
Hidden hearing loss, a term coined by Schaette and McAlpine (2011), has been used to describe such a disorder in humans
A partial loss of auditory nerve fibers from noise-induced synaptopathy will result in reduced neural output from the cochlea while maintaining auditory sensitivity
This could theoretically result in difficulty with temporal coding leading to exacerbated difficulty understanding speech in noisy situations

Question 18

Is a hidden hearing loss generally undetectable by standard audiometry?

Answer 18

Yes
Not caught by normal pure tone audiometry
Characterized by abnormal ABR

Question 19

What other conditions can lead to a hidden hearing loss?

Answer 19

Demyelinating conditions
Such as guilliain barre and friedrich’s ataxia
Likely due to transient schwann cell loss of auditory nerves

Question 20

Should cognitive decline be included in the definition of hidden hearing loss?

Answer 20

No
Cognitive decline is not specific to the auditory system

Question 21

Is it clear that peripheral hearing loss alone cannot account for all the listening difficulties exhibited by older listeners?

Answer 21

Yes
It also is evident that the peripheral pathology can cause secondary structural and functional changes in the CANS that further impacts listening and perception

Question 22

What does normal age-related changes in cognitive function affect?

Answer 22

Working memory
Information processing speed
Attention
Information sequencing abilities

Question 23

Is speech dependent on a combination of auditory, cognitive, and linguistic abilities?

Answer 23

Yes
The process of temporarily maintaining incoming sensory information for cognitive processing is known as working memory
Once a speech signal is at least partially audible, the incoming stream of acoustic information must be temporarily maintained so that it can be compared to the listener’s accumulated linguistic knowledge in long-term or semantic memory
Which in turn, contributes to the process of speech recognition

Question 24

What is the ease of language understanding (ELU) model?

Answer 24

A theoretical model has been developed to describe the relationship between cognitive processes and speech understanding
Describes the relationships between the listener’s cognitive resources, stimulus factors, and the listener’s knowledge of language and experience
*Often referred to as semantic and episodic long-term memory

Question 25

What is a key component for ELU?

Answer 25

Working memory capacity will predict individual differences in speech recognition, with adult listeners using both verbal and visuospatial measures of working memory capacity

Question 26

What did Raz, Willerman, and Yama say about cognition?

Answer 26

Hypothesize that more intelligent brains may have better signal representation and sensory resolution
Due to greater hardware redundancy that facilitates resolution of signals of low redundancy
Working memory appears to play a significant role in auditory processing (the faster the task is completed, the less decay will occur - individuals who can process information faster will effectively have more working memory available to process new information)

Question 27

What is the resource allocation model?

Answer 27

An alternate opinion on why older adults perform poorly on CAPD tests
The presence of perceptual deficits caused by a peripheral pathology results in the need for greater resources to be allocated to auditory processing
Leaving fewer resources available upstream for central cognitive processes required for storage and retrieval of auditory information
Studies supporting this hypothesis have found that even mild hearing loss can result in a misdiagnosis of dementia
*Auditory processing deficits may lead to poor performance on cognitive tests and influence results on psychiatric assessments

Question 28

Can normal aging older adults draw upon their linguistic experience to compensate for their sensory and processing deficits?

Answer 28

Yes
Older adults are better than young adults in using context to recognize words
Better able to rely on previous linguistic knowledge and short-term conceptual memory when recognizing accelerated speech
The ability to make use of prosodic information to recognize the spoken word is preserved in normal aging
*Well developed top-down abilities allow older adults to function and compensate for the reduced redundancies they encounter in the speech signal

Question 29

What is another factor besides the peripheral auditory system and cognition that accounts for performance decrements in older adults?

Answer 29

Age-related changes in auditory neurophysiology
Decrease in neurons with age especially in the superior temporal gyri, pre-central gyri, and areas around heschel’s gyrus
Also a decrease in volume of the ventral cochlear nucleus after the 5th decade (associated with decreased myelination and number of blood vessels)
Also a decrease in size and degree of myelination of the corpus callosum

Question 30

Is the corpus callosum important for integration of information?

Answer 30

Yes
Older adults show poorer performance on binaural integration and dichotic listening tasks
From animal models, it appears that the auditory segment of the corpus callosum is in the posterior portion, specifically in the splenium
Age-related asymmetries in dichotic listening are probably related to loss of efficiency of interhemispheric transfer of auditory information due to callosal dysfunction
This in turn can lead to increased divergence of processing abilities for right and left ear inputs (older adults may start to show a right ear advantage again)

Question 31

Is there also a difference in performance between verbal and non-verbal tasks for older adults?

Answer 31

Yes
Older adults showed increasing LE deficit on verbal tasks and an increasing RE deficit on non-verbal tasks
These findings persist even after peripheral asymmetries in hearing sensitivity are accounted for
*Similar results on verbal tasks were found in individuals with MS and cranial trauma

Question 32

What is the test battery of assessing CAPD in older listeners?

Answer 32

Case history
Hearing evaluation (because perceptual problems are associated with hearing loss, thresholds are needed for CAPD tests, and results are affected by the presence of hearing loss)
Tests for language and phonological processing
CAPD behavioral tests (if age-appropriate adult norms are available)
Cognitive/psychological evaluation
Physiologic tests (auditory evoked responses show age-related changes such as increasing latency and decreasing amp)

Question 33

What is the biggest hurdle in developing an age-appropriate normative CAPD test battery for older adults?

Answer 33

Older adults is not a homogenous group
They age at different rates, not entirely based upon chronological age
That means levels of hearing loss, cognitive abilities, and short-term memory variables would make any standardization across age quite challenging
*Reason why McFarland and Cacace advocated for the use of a test of short-term memory that was insensitive to long-term memory, verbal skills, and motor sequencing skill

Question 34

Is the SSI a useful test for assessing CAPD in older adults?

Answer 34

Yes
Because of reduced dependence on memory and linguistic abilities
SSI depends on visual cues, which may be a limitation for adults with visual problems
SSI-ICM is more sensitive to lower brainstem lesions
SSI-CCM sensitive to temporal lobe lesions with the ear contralateral to the lesion showing greatest deficits

Question 35

Does the SSI show a maturation effect?

Answer 35

Yes
Test scores improve in successive age groups from 8 to 25 years
Test scores deteriorate sharply from 60 to 90 years

Question 36

Can PB-Max and SSI-ICM provide a peripheral-central ratio?

Answer 36

Yes
Can be useful in judging prognosis of hearing aids or other rehabilitative measures
A patient can be their own control

Question 37

Are auditory closure deficits more apparent in individuals with inefficient top-down processing?

Answer 37

Yes
Seen in language-related or attention deficit disorders
Auditory closure deficit demonstrates a breakdown in intrinsic redundancy of CANS reducing/eliminating repeated representation of incoming signal through auditory pathways
Any condition that reduces the extrinsic redundancy of signal may reduce the ability to achieve auditory closure
Attention an play a role in auditory closure and phonemic decoding may be affected

Question 38

Do noise factors affect auditory closure?

Answer 38

Yes
“Noise” could be noise, but it also could be other speech, music, or tv sounds
Noise factors affecting auditory closure could be language, attention, executive function deficits, short term memory, and related issues that reduce extrinsic redundancy of speech

Question 39

What tests will adults and children with auditory closure deficits perform poorly on?

Answer 39

Low-pass filtered speech test
Speech in noise tests
Time-compressed speech tests
*All of these tests reduce the redundancy of speech

Question 40

Will individuals with difficulty in frequency discrimination and poor acoustic recognition perform poorly on the PPST?

Answer 40

Yes
They will demonstrate difficulty with prosody (stress, rhythm, and intonation)

Question 41

What can difficulty with prosody lead to?

Answer 41

Difficulty extracting words from spoken message
Difficulty extracting intent, meaning, and emotion from spoken message
Individuals may be “flat” (monotonic) readers

Question 42

When can a diagnosis of CAPD be made?

Answer 42

Diagnosis of (C)APD can conclusively be made after problems in other modalities have been ruled out
Interpretation of test results is most straightforward when deficits are unilateral (unilateral results indicate that the patient understood the task and the outcome was not due to a linguistic, cognitive, or attention disorder)
*Unilateral left ear deficit is one of the most definitive and most observed patterns on the CAPD test battery

Question 43

Is reduced performance only on the more difficult auditory portions of a test a definitive CAPD test battery pattern?

Answer 43

Yes
This finding implies an auditory deficit versus linguistic, cognitive, or strictly attention deficit

Question 44

Are phonemic and linguistic imprints of a language most strongly implanted in childhood?

Answer 44

Yes
During the most plastic period of early language learning
Language learned after the critical plastic period may not leave as strong as imprint
Presented in a study in 1980

Question 45

Do linguistic limitations imposed on languages learned after early childhood become more pronounced with aging?

Answer 45

This also explains why learning a second language is difficult for students with a hearing loss and for older adults
Weakening of the language becomes more pronounced with age

Question 46

Do factors other than hearing loss, such as second language acquisition, play a role in speech processing in noise?

Answer 46

Yes
In quiet, word and sentence recognition abilities of the ELLs were equivalent to native English speakers
But in noise, the ELLs had significantly poorer scores
For older ELLs with a hearing loss, adverse listening environments such as noise and reverberation could be even more detrimental to speech understanding than age-matched native English speakers
Because of some level of hearing loss, older listeners rely heavily on contextual cues especially in adverse listening environments, but older ELL are less likely to utilize contextual cues because it may be harder for them to pull out important speech cues that are embedded in the noise as a result of limited linguistic experience

Question 47

How do you manage older adults with CAPD?

Answer 47

Remediation of central auditory processing (CAP) deficits in the older adult are similar to those used for the hearing impaired
Bottom-up approach (to enhance acoustic skills through amplification, improve SNR through FM or remote mic, and train specific auditory skills)
*Signal audibility can be corrected by amplification, at least to some degree, but a significant improvement in speech perception may not be observed for all older adults because of involvement of the CNS
Top-down approach (used to provide compensatory strategies to minimize the impact of CAPD through strengthening of higher order central resources such as language, memory, and attention)

Question 48

Is phonological processing inherent to language learning and reading?

Answer 48

Yes
Older individuals with speech perception deficits resulting from auditory deprivation and poor phonological processing skills also may benefit from rhyming activities
Because it may help regain some of their lost processing abilities

Question 49

Are both top-down an bottom-up training principles important to be applied across all settings?

Answer 49

Yes
Clinic
Work
Home