Should audiologists measure cognition: How and why? · Should audiologists measure cognition: How...

Should audiologists measure

cognition: How and why?

Kathy Pichora-Fuller

Professor, Psychology, University of Toronto

Adjunct Scientist, Toronto Rehabilitation Institute, University Health Network

Adjunct Scientist, Rotman Research Institute, Baycrest Hospital, Toronto

Guest Professor, Linneaus Centre HEAD, Linköping University, Sweden

Funded by CIHR, NSERC, & Hearing Foundation of Canada

Outline (Part I – “Healthy Adults”)

Relevance of cognition for listening

Gains and losses in health cognitive aging

Cognitive processing declines and listening

Use of context and compensation

Brain plasticity and training

New ideas for listening training

Prevalence of Hearing Loss in Older Adults

Audiometry (e.g., Plomp, 1978; Moscicki et al., 1985; Willott, 1991)

65 years 24%

70 years 30%

75 years 50%

57-89 years 83%

75% of people with hearing loss are > 75 years old

Average first time hearing aid user ~ 70 years

Audiograms and Age (ISO 7029)

HF audiometric threshold elevation

OHC (also noise-induced hearing loss)

Endocochlear potentials ~ stria vascularis

Neural – loss of synchrony

(Mills, Schmeidt, Schulte, & Dubno, 2006)

Women Men

3kHz 3kHz

Speech Understanding in Noise

Little problem in ideal listening conditions Quiet

One talker

Familiar person, topic, situation

Simple task, focused activity

Difficulty in challenging listening conditions Noise

Multiple talkers

Strangers, accents, new topic, novel situation

Complex task, many concurrent activities

Fast pace

Hearing aid

Avoid by withdrawal from social interaction!

Speech Perception in Noise (Pichora-Fuller, Schneider, Daneman, JASA, 1995)

8 lists of 50 sentences

Half low-context

John did not talk about the spoon.

Half high-context

Stir your coffee with a spoon.

Repeat last word of sentence

Vary S:N

(Sometimes also recall)

Old need 3 dB better S:N

Context helps

3 dB

YOUNG

OLD

OLD HL

Speech, Spatial & Qualities of Hearing Scale (SSQ; Noble & Gatehouse, 2004;

Bahn, Singh, Pichora-Fuller, JAAA, 2012)

Older “normal” vs HL

Older vs Younger Adults

Older “normal” hearing for age

with clinically normal audiograms up to 4 kHz

SSQ and Behavioural Hearing Tests:

Not Significantly Correlated

Pure-tone Average

(dB HL)

Words-in-Noise (WIN)

50% threshold (dB SNR)

SSQ Items with Largest Age-related Differences

Speech

Conversing in adverse environment

Conversation in reverberant environment 1.7

Talking with a person in continuous noise 1.6

Focusing, switching attention

Ignore interfering voice of different pitch 1.9

Following conversation switching in a group 1.6

Young - Old score

(10-point scale)

Speech Understanding in Noise

CHABA Report (1988).

J Acoust Soc Am, 83, 859-895

Peripheral auditory

Central auditory

Cognitive

Interactions of sensory and cognitive aging Schneider BA, Pichora-Fuller MK, Daneman M. The effects of

senescent changes in audition and cognition on spoken language

comprehension. In: Gordon-Salant S, Frisina RD, Popper A, Fay D,

eds. The Aging Auditory System: Perceptual Characterization and

Neural Bases of Presbycusis. Berlin: Springer; 2010:167-210

Outline (Part 1)







What Changes in Cognitive

Development over the Lifespan? (Craik & Bialystock, Handbook of Cognitive Aging, 2008)

Representation (KNOWLEDGE)

-vocabulary

- world knowledge

- expertise

Context

(reliance, benefit from SUPPORTIVE ENVIRONMENT)

Control (PROCESSING)

-working memory

-processing speed

-divided attention

-sensory

Younger Older

Bottom-Up &Top Down Processing Effortful listening

Bottom-up processing less efficient

Top-down processing more necessary

Bottom-up (ear to brain) Analysis of acoustic signal

Better signal (faster)

Poorer signal (slower)

@ amount & type of distortion

Top-down (brain to ear) Priming (pre-signal)

expectations facilitate recognition (faster)

Disambiguation (post-signal) knowledge constrains alternatives (slower)

Repair (post-signal) Fill in gaps or correct errors (slower)

Sound

Meaning

Bo

tto

m u

p

Knowledge

To

p D

ow

n

As Processing Effort Increases

Extreme demand: Accuracy drops

But if accuracy remains high,

increased processing (cognitive effort/load)

is manifested by

Reduced working memory span

Slower speed

Problems dividing attention (dual task)

Working memory

System responsible for the PROCESSING and

temporary STORAGE of information

during the performance of all complex cognitive tasks,

including comprehension

assumed to have a limited capacity that must be

shared between processing and storage

(Baddeley, 1976; Daneman & Carpenter, 1980)

Attentional control and speed of processing

Spectrograms for Jittered and

Intact Sentence in Babble

Effect of Simulated Auditory Aging

on Working Memory Span

Measuring Working Memory:

Why and How…. Fred

Mary

Fred in Quiet

Fred in Noise

Fred in More Noise

Processing Storage

If task demand does not exceed capacity, would recognition accuracy be reduced?

If task demand does exceed capacity, would recognition accuracy be reduced?

If WM measured on-line, would it correlate with performance (accuracy, speed, effort)?

INTER-

Off-line

WM = 5

WM = 7

INTRA-

On-line

WM = 5

WM = 3

WM = 1

Are Older Adults Special?

Audibility (audiogram) is primary but not a special aging factor (Humes, 2003, JAAA 2007)

If audibility factor is minimized

Age-related auditory temporal processing issues emerge Especially in challenging listening conditions

Complex speech (e.g., sentences)

Complex backgrounds (e.g., competing talkers)

Critical age differences when conditions become challenging Older listeners need 2-3 dB better S:N than younger listeners

Cognitive factors important in challenging conditions!!! Regardless of age

Regardless of audiogram

Word Span with NU6s (Smith, Pichora-Fuller, Alexander, Wilson, & Anderson, in prep)

Word Recognition Judgment Recall

RICE

FIST

RISK

GRACE

BAR

SHOVE

WHAT

MOON

CALF

THAT

√ X, Fish

√ √ √

√ Rice,

Fish, √ Risk, √ Grace, √

√ √ √ √

√ X, Car

√

√

X

√

X

X

Card, X

Shove, √

√ √ √ √

√ √ √ √

What, √

Moon, √

Rice, √

That, √

NONE

OBJECT

ALPHA

YOUNGER

OLDER

ME

AN

NU

MB

ER

OF

WO

RD

S P

ER

SE

T S

IZE

2

3

4

5

6

SET SIZE

2 3 4 5 6

2

3

4

5

6

RECOGNITION

RECALL

OHL Recognition

Recall

Cognitive Aging

Gains:

Knowledge is preserved

and context is helpful

Losses:

Processing

Working memory

Slowing

Attention/Inhibition

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Younger

Intact

Younger

Jitter

Older Intact

Be

ne

fit

fro

m C

on

tex

t (d

B S

NR

)

2-3 dB

LOW

HIGH

Cognitive Neuroscience of Aging

Same performance achieved with different processing

More widespread activation ~ brain reorganization

Young brain activity more lateralized

Old brain activity more distributed

Deterioration or compensation?

HAROLD: Hemispheric asymmetry reduction in older adults

(Cabeza, 2002)

PASA: Posterior-anterior shift in aging

(Davis, Dennis, Daselaar, Fleck & Cabeza, 2008)

Context, Intelligibility & Brain Activation (Obleser, Wise, Dresner & Scott, 2006)

High vs. low predictability at

intermediate signal quality for

younger adults listening to

distorted (noise-vocoded) SPIN sentences

Activation to HIGH-CONTEXT >

LOW-CONTEXT speech

Various areas activated including the

left dorsolateral prefrontal cortex

(working memory & semantic processing)

Compensation (Grady, 2012, Nature Reviews Neuroscience, 13, 491-505)

low high

Task Demands (Pichora-Fuller & Jamieson, 2012)

Task 1 depends mostly on auditory

capacity (e.g., detecting a sound).

Task 2 depends more on cognitive

capacity (comprehending a lecture).

Task 3 depends even more on

cognitive capacity (dividing attention

during group conversation).

P1 is a person with normal hearing

and slightly below average cognitive

capacity who has sufficient combined

capacities to succeed on all 3 tasks.

P2 is a person with hearing loss and

high cognitive capacity who is able to

succeed on all 3 tasks by using

cognitive capacity (world and linguistic

knowledge) to help compensate for

deficits in auditory processing.

Co

gnit

ive

Cap

acit

yLo

w

Hig

h

Low HighAuditory Capacity

Task 3

Task 1

Task 2

P1

P2

Cognition & HA Benefit Correlated

Landmark 2003 studies

(Gatehouse et al.; Humes; Lunner) Those with higher cognitive function

do better with complex, fast-acting signal processing

Those with lower cognitive function

do less well with such complex devices

Cognition matters in challenging conditions

Why?

How measure cognitive status? To predict or guide treatment

(HA fitting, training)

As a new outcome measure

Lunner & Sundewall-Thorén, JAAA 2007 N = 32 experienced HA users

Replicates earlier studies (Gatehouse et al. 2003, 2006) with sentence tests

Explained SNR variance

from hearing loss and cognitive performance

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

Slow&Unmod. Slow&Mod. Fast&Unmod. Fast&Mod.

Test condition

Ex

pla

ine

d v

ari

an

ce

PTA(6)

VLM

Cognitive Hypotheses & Training Cognitive Compensation Hypothesis (Li, Krampe, & Bondar, 2005; Li & Lindenberger, 2002)

declining sensory (and motor) functions are

compensated by higher-level cognitive and attentional processes

CRUNCH - Compensation-Related Utilization of

Neural Circuits Hypothesis (Reuter-Lorenz & Cappell, 2008)

additional brain regions are recruited by older adults when capacity limits are

reached in a given task or combined tasks.

STAC - Scaffolding Theory of Aging and Cognition (Park & Reuter-Lorenz, 2009)

there is the potential to enhance such compensation by training.

Outline (Part IB)







New Rehab Approaches Pichora-Fuller, M.K. (2013). Auditory and cognitive processing in

audiologic rehabilitation (pp. 519-536). In J. Spitzer & J. Montano

(Eds.), Adult audiologic rehabilitation: Advanced practices (2nd edition).

Plural Publishing, San Diego, CA.

Ease of Listening

1. Semantic priming

2. Stream segregation

3. Spatial expectation

4. Emotional consistency

Speed and Ease of Processing

As adults age:

Auditory temporal processing declines

Cognitive information processing slows

Auditory and cognitive aging can combine to

make listening sluggish

Easier listening is reflected in faster listening

Reaction time or online measures could reveal

differences in speed/ease when accuracy

measures are near ceiling and insensitive

Lexical decision reaction time

in younger and older listeners:

The effects of semantic context and

the type and amount of acoustical distortion

- Preceding context distorted or intact Target intact

Congruent Stir your coffee with a spoon. (yes)

Neutral Its name is grock. (no)

Incongruent Stir your coffee with a risk. (yes)

- Measure RT when lexical decision correct

- Facilitation (RT neutral context – RT congruent context)

Goy, H., Pelletier, M., Coletta, M., & Pichora-Fuller, M.K. (in press).

Journal of Speech, Language and Hearing Research.

Huiwen Goy

Increasing Distortion of Context Only

Slows Lexical Decision for Intact Items

None

Some

More

Effects of Distorting Context on

Speed of Lexical Decision

90

45

• Older listeners’ RTs are more facilitated by context.

• Signal distortion reduces facilitation.

Speed (and Ease) of Listening

Signal quality affects listening:

Faster if signal is intact

Slower if signal is distorted or degraded or noisy

Could be influenced by hearing aid processing

Context affects listening:

Faster if context is semantically congruent

Slower if context is semantically incongruent

Could be influenced by AR training

New Rehab Approaches

Ease of Listening

1. Semantic priming




Speech-on-Speech Listening Ezzatian, Li, Schneider & Pichora-Fuller, submitted

Circles : intact two-talker speech masker condition.

Diamond : time-reversed two-talker speech masker.

Triangles pointing up : 3-band noise-vocoded speech masker condition.

Triangles pointing down: 16-band noise-vocoded speech masker condition.

Squares: precedence-effect speech masker condition. Dotted lines – word position effect; solid lines – no word position effect

Payam Ezzatian

New Rehab Approaches

Ease of Listening

1. Semantic priming




Spatial Attention (based on Kidd et al., 2005)

“Ready Hopper,

go to white 2 now”

“Ready Charlie,

go to blue 1 now”

“Ready Baron,

go to green 8 now”

• Callsigns = Charlie, Hopper, Baron, etc.

• Probability of target at the centre location (1.0, 0.8, 0.6 0.33)

• Simple vs Complex instruction

• Task: Identify colour and number with target callsign

Ready Charlie, go to

[colour] [number] now.

10%

10%

80% Gurjit Singh

Likely

Unlikely Unlikely

Task Complexity Hurts Older Adults

if Target at Unlikely Location Singh, Pichora-Fuller, Schneider, JASA 2008; in press, Ear & Hearing

New Rehab Approaches….

Ease of Listening

1. Semantic priming




Emotion & Word Recognition (Dupuis & Pichora-Fuller, in prep; Dupuis PhD)

Mixed vs. Blocked; Young > Old ~ 11% vs. 6%

FEAR SAD

Kate Dupuis

Listening in Noise ~

Driving Uphill in Snow • Low gear (effort)

• Slow down (speed)

• Keep moving (continuity)

• Monitor space (expectations)

• Stay calm (emotion)

• Expertise (training)

• Snow tires (technology)

• Get where you want to go

• Stay safe

Outline ( Part 2 – Dual Hearing

and Cognitive Loss)

1. Links between hearing loss and dementia

2. Diagnosing MCI and dementia

3. Hearing and cognitive assessment

4. Rehabilitation

Pichora-Fuller, K., Dupuis, K. Reed, M. & Lemke (in press).

Helping older people with cognitive decline communicate:

Hearing aids as part of a broader rehabilitation approach.

Seminars in Hearing.

Cognitive Impairment

Canadian Study of Health and Aging

(Ebly et al., 1994)

Dementia

75-84 years: 15%

85-89 years: 23%

90-94 years: 40%

> 95 years: 58%

Of adults 75-84 years old living in community

15% have dementia

http://www.alzheimer.ca/en/Get-involved/Raise-your-voice/Rising-Tide










Hearing Loss Associated with Dementia

Gold, Lightfoot & Hnath-Chisolm (1996)

27 of 30 (90%) patients with Alzheimer’s had

hearing impairment (pure-tone screen & HHIE)

Uhlmann et al. (1989)

Case-control study with 100 pairs

Prevalence of hearing loss significantly higher in

those with Alzheimer’s-type dementia

Hearing loss significantly correlated with MMSE

Lin et al. (2004) Dual sensory loss associated with greatest odds for

cognitive decline and for functional decline on five

everyday activities over a period of four years

Dual Sensory (Hearing & Vision) Loss

Self-reported DSI (Caban et al., 2005) 3% in general population

17% in adults > 80 years

Clinical measures in 400 veterans (Smith et al., 2008) 42-75% depending on criteria for HL

100 in each of 4 age groups (<65, 65-74, 75-84, 85+ yrs)

Unaided > 40 dB HL pure-tone average threshold in better ear

Regular PTA (.5, 1 & 2 kHz) vs high-frequency PTA (1,2 & 4 kHz)

7.4% vision impairment overall Best corrected acuity less than 20/40 (legal blindness)

> 20% dual loss in veterans > 85 years

“Central Auditory” (Speech in Noise)

Problems May PRECEDE Dementia Longitudinal epidemiological studies

Gates et al. (1996)

N >700, speech in competing speech test (SSI-ICM) in

those without stroke, dementia, or HL (PTA 40 dB HL)

MMSE administered 2, 4, 6 years later

Those with low scores on SSI-ICM were 6-12 times more

likely to develop clinical dementia

Gates et al. (2002, 2008)

Similar results for longer follow-up period (3-12years)

Pure-tone HL related to incident

dementia Lin, F. R., Metter, E. J., O’Brien, R. J., Resnick, S. M., Zonderman,

A. B., & Ferrucci, L. (2011). Hearing loss and incident dementia.

Archives Neurology, 68(2), 214-220.

Lin FR, Ferrucci L, Metter EJ, et al. (2011). Hearing loss and

cognition in the Baltimore Longitudinal Study of Aging.

Neuropsychology, 25, 763-770.

Lin FR. (2012). Hearing loss in older adults. Who’s listening? JAMA,

307, 1147-1148.

Lin FR, Yaffe K, Xia J, et al. (2013). Hearing loss and cognitive

decline in older adults. JAMA Intern Med, 173, 293-299.

Central Auditory Tests (DDT)

Idrizbegovic E, Hederstierna C, Dahlquist

M, Nordström CK, Jelic V, Rosenhall U.

(2011).

Central auditory function in early Alzheimer's

disease and in mild cognitive impairment.

Age Ageing, 40, 249-254

Outline ( Part 2)




4. Rehabilitation

When does cognitive aging start?

Chronological Age

10 20 30 40 50 60 70 80 90

Z-S

core

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

Synonym Vocabulary

Pattern Comparison (Speed)

Raven's (Reasoning)

Recall (Memory)

84

50

16

Pe

rce

ntil

e o

f P

op

ula

tion

Salthouse (2004) Current Directions in Psychological Science

New View

Cognitive decline as a continuum

Healthy aging

MCI

Dementia

Figure 1. Estimates of age-specific prevalences of Alzheimer’s disease (AD),

Mild Cognitive Impairment (MCI), and Non-Affected (NAs), aged 60–85,

assuming 1.0% rate for conversion from NA to MCI at age 60.

(Adapted with permission from Yesavage JA, O’Hara R, Kraemer H, et al.

Modeling the prevalence and incidence of Alzheimer’s disease and

mild cognitive impairment. J Psychiat Res 2002;36:281-286.)

Changes in cognitive functioning Declines in memory, learning, attention, and

judgment

Disorientation in time and space

Difficulties in word finding, communication

Declines in personal hygiene

Inappropriate social behaviour

Personality changes

Symptoms and Diagnosis

Most common form of progressive, degenerative, and fatal

dementia accounting for up to 60% of all cases of dementia

Neurological changes in Alzheimer’s disease

Microscopic

Rapid cell death in hippocampus, cortex, basal forebrain

Neurofibrillary tangles (beta-amyloid protein)

Neuritic plaques

Neurotransmitters altered

Alzheimer’s Disease

Vascular Dementia – CVA (stroke)

Parkinson’s Disease Associated with dopamine deficiency

14% to 40% will develop dementia

Huntington’s Disease Associated with GABA deficiency

Alcohol Dementia Complex Wernicke-Korzakoff’s Disease

AIDS Dementia Complex (ADC)

Other Forms of Dementia

Sundowning – symptoms worse in the evening

Wide variation in the rate of deterioration Wandering

Incontinence

Loss of personhood

Past: definitive diagnosis depends on autopsy

Now: possible to measure in brain (plagues/tangles)

Comprehensive and broad diagnosis can be

reasonably accurate pre-mortem

Treatable causes of Alzheimer’s-like dementia

must be ruled out

Symptoms and Diagnosis

7 (2011) 270–279.

Outline ( Part 2)




4. Rehabilitation

Hearing Loss Can Impair Performance

on Any Task Using Auditory Stimuli

Weinstein & Amsel (1986) N=30 institutionalized elders with senile dementia

10 of 30 reclassified to less severe category of

dementia when retested with amplification

(83% had hearing loss > 25 dB HL, significantly

higher than comparison sample w/o dementia)

MoCA

www.mocatest.org

N=301

N=122

Effect of Background Noise on MoCA Scores Dupuis, Marchuk, Pichora-Fuller, Chasteen, Singh, & Smith, submitted

(Aging, Neuropsychology and Cognition)

Speech 50 dBHL

Babble 30 dBHL

Babble 62 dBHL

20 per group

Veronica Marchuk

Assessing Person with Dementia Marilyn Reed, Canadian Hearing Report, in press

• Give short, simple instructions • Practice, to ensure instructions are understood • Provide prompting and encouragement • Accept a variety of responses • Get most valuable information first (i.e., minimize fatigue, agitation) • Speech testing (meaningful stimuli) more successful that PTs; SRTs

more reliable than PTTs • Obtain SATs where SRTs unobtainable • Use any speech material that is effective; meaningful/familiar speech

(simple questions or digits more successful than PBs or spondees) • Test at time of day when most alert (usually morning) • Presence of caregiver/family member may reduce agitation or anxiety • Assess over multiple sessions if needed • Include speech in noise and CAP test (s) appropriate to capability • Objective assessment; acoustic reflexes, ABR (OAEs unlikely)

Outline ( Part 2)




4. Rehabilitation

Aging & Communication

Hearing Loss

Vision Loss

Cognitive Loss

Mobility Loss

Clinically

Normal

http://www.iso.org/iso/pressrelease.htm?refid=Ref1397

http://www.iso.org/iso/pressrelease.htm?refid=Ref1397

Doing the math in the clinic? in life?

NORMAL

NORMAL

NORMAL

BLINDNESS

DEAFNESS

DEMENTIA

Degree of Impairment

Auditory

Visual

Cognitive

Stave off and Slow Decline

Possible Protective Factors

Occupational

Education

Bilingualism

Employment

Social Activity

Cognitive Activity

Volunteering

Physical

Being male

Genetics

Cardiovascular health

Diet

Exercise

Scarmeas et al. (2009) JAMA, 302, 627-637.

Interactive Effects of Physical Activity and Diet

Mild Cognitive Impairment (e.g, Troyer & Murphy, 2007)

Active lifestyle ~ risk of future dementia Cognitive engagement

Tasks involving problem-solving, decision-making, learning, remembering new information

Social interaction Rich social stimulation and active social network

Participating in group activities and interactions

Physical activity Some activities are done in groups, with music

Enriched environments

Group interventions

Communication-related disorders???

Kelly Murphy

MCI Memory Intervention Program

Goals Increase knowledge about practical and effective

memory strategies

Increase use of targeted strategies in everyday memory situations

Change beliefs about memory function and factors influencing memory function

Improve memory performance on objective memory tasks

Troyer, Murphy, Anderson et al., (2008).

Neuropsych. Rehab, 18, 65-88

MCI Memory Intervention Program • Group intervention

• Detailed handouts

• At-home assignments

• Concurrent sessions for families

• Memory Strategies

• Knowledge (Know) • Use in everyday life (Use out) • Use in laboratory (Use in)

• Memory Beliefs • Memory Performance



MCI Memory Intervention Program

Week 1st hour 2nd hour - MCI 2nd hour - family

1 What is MCI?

Overview of Strategies

Memory book MCI and

dementia risk

2 Stress and Relaxation Memory book Safety

3

Stress & Relaxation

follow-up

Spaced Retrieval Behavioural

Coping

4 Nutrition Semantic

Association

Nutrition

5 Community Resources Intentions Cognitive Coping

6 Recreation Strategy

Application

Planning ahead



Cognitive Benefits of Better Hearing Arlinger, Lunner, Lyxell, & Pichora-Fuller, SJP, 2009

Older adults using hearing aids have better emotional and social well-being and greater longevity

(Appolonio et al., 1996; Cacciatore et al., 1999; Naramura et al., 1999; Seniors Research Group, 1999)

Reduced rate of decline in scores on a cognitive screening test over

a six-month period following intervention with hearing aids

(Allen et al., 2003)

Slower cognitive decline in Alzheimer’s cases with better hearing

(Peters, Potter, & Scholer, 1988; Wahl & Heyl, 2003)

Hearing aid use reduced problem behaviours judged by caregivers of adults with dementia

(Palmer et al., 1998)

Hearing Aid Fitting & Dementia Handling and Care:

Automated features, minimal manual controls

Remote controls intuitive/user friendly

Verbal prompts

Manageable battery doors (marked if low vision)

Removal cords

Safety loops for attachment to clothing for advanced CI

Facilitate phone use with hearing aid, so not removed

Establish routine for storage once removed

For previous users:

do not change style (or manufacturer) of aid

do not change battery size or style of door

Accessories to improve SNR (remote microphone, FM compatible)

Training:

Longer acclimatization period (6 -12 months)

Written instructions (large print, pictures, supported communication)

Schedule prompt and more frequent return visits

Counseling and AR; group/social model

Involve/instruct caregivers in management and AR

Good Hearing Health Could

Promote Good Cognitive Health

PRESERVE

communication and social interaction

• stave off social isolation

• slow cognitive decline

Kate Dupuis Marilyn Reed Ulrike Lemke-Kalis

Vancouver, British Columbia

World Congress of Audiology

September 18-22, 2016

Should audiologists measure cognition: How and why? · Should audiologists measure cognition: How...

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