Gail M. Whitelaw, Ph.D. Department of Speech and Hearing Science The Ohio State University

1. Hearing and Listening in Adults: What’s the brain got to do with it?Colorado Academy of AudiologyOctober 5, 2012 Gail M. Whitelaw, Ph.D. Department of Speech and Hearing Science The Ohio State University Columbus, OH whitelaw.1@osu.edu

2. Focus of the presentation • Discuss a lifespan perspective of auditory development and how this perspective influences the assessment of hearing and listening in adults • Cognition • Describe how World Health Organization concepts of impairment, activity limitation, and participation restriction apply to assessment and treatment of hearing and listening skills in adults. • List test protocols and tools that assist with assessment and treatment • Describe examples based on cases presented

3. So, why am I here today? • The “talk about auditory processing without talking about auditory processing” talk • However, the definitions of auditory processing have expanded significantly • All the things patients have told us for years that are not explained by the audiogram are now supported by evidence • EXCITING time to consider these issues because of how much research has been presented recently

4. A theme is that “everything old is new again” however now we have evidence to support what we have known Exciting time for audiology…can enhance what we can do and change patient care

5. Developmental aspects of audition across the lifespan • Hoping to generate some excitement about auditory skills beyond the audiogram • Erber’s hierarchy • Detection • Discrimination • Identification • Comprehension • Historically, as a profession, we have focused on “detection” • What the audiogram “says” vs. what the patient says

6. Old news applied to new issues:“The conventional auditory acuity tests have little predictive value of auditory behavior in more complex social situations….”Karlin (1942)

7. Many of you most likely incorporate this into your patient care… • The simple explanation for patients when first fit with amplification “hearing happens in the brain, not the ear” • We have been aware of this for many years… work by Stuart Gatehouse and acclimatization • A great start but now we have much more evidence

8. Hearing • Passive perception of sound • Access to auditory information by detection • Functions “lower level”…truly, at the bottom • Processing required is minimal

9. Listening • Active • The ability to access auditory information • Intention and attention are involved

10. Auditory function is much broader: • Hearing • Listening • Comprehension

11. Bottom up/top down (BU/TD) • Historically, audiologists have focused on “bottom up” processing • Top down focuses on how information is available for quick recall, application to language information • “…to apply meaning to complex sound structures such as language and music” (Beck, 2012) • Broader perspective of top down…those of us who do APD had a more limited definition in the past

12. Starting to recognize concepts like “working memory” related to “hearing loss” • Working memory refers to both processing of information and storage of information • When we define “hearing loss”; it’s often much less significant on an audiogram than previously thought

13. Starting to recognize concepts like “working memory” related to “hearing loss” • Baltimore Longitudinal Study on Aging • Neuropsychology working with audiology • Postulated that greater degrees of hearing loss would be associated with memory and executive functioning deficits • Found a reduction of processing speed, working memory and executive functioning of 6.8 years with a 25 dB hearing loss • Controlled for other factors • Lin et al (2011)

14. How is audiology “essential”? • Surprising findings and their relevance • The “7-10 year wait” to get hearing aids • A “little hearing loss” may not be so little in terms of impact • Again, the audiogram may have little relevance: exciting and scary • Partnerships with neuropsychologists • Other types of issues: People with tinnitus complain about attention; mechanisms are likely broader than those of just the auditory system • Start to think outside the audiogram “box”

15. Relationship between cognition and hearing Issues include • Language processing in challenging listening environments • Using auditory communication technologies or the visual modality to boost performance • Changes in performance based on development, aging, and/or rehabilitative training

16. Framing “hearing” in a broader perspective • Spatial hearing (both younger and older listeners benefit from spatial information and knowing “where to listen” when it’s not predictable) • Listening for speech sounds • Listening for non-speech sounds • Selective attention (relevance of auditory information)

17. The role of cognition for all listeners • Allows listening to focus on a target • Supports more complex processing of information • Compensates by drawing on context and non-auditory issues (top down) • Precision and uncertainty • Singh (2012)

18. Framing “hearing” in a broader perspective • Even our familiar territory of speech in noise abilities • Hearing loss or audibility remains a primary predictor of speech perception • However, there is a clear link between cognition and speech perception in noise • Akeroyd (2008)

19. Interest in these issues in older adults with noted cognitive decline • Kricos (2006) • Beck and Clark (2009) • Information degradation hypothesis suggests that many of the difficulties older adults with hearing loss experience in comprehension are cognitive slowing • Difficulties that some older adults have with advanced hearing aid technology may be related to listening experience and cognitive abilities

20. Hearing and the Brain • The Hearing Review; September 2012 • Great articles on cognition and hearing • Much of the focus is on older adults and cognitive slowing and what this means related to use of amplification

21. Cognitive issues are likely to be a significant yet overlooked factor in younger adults Not due to “dementia” but in a number of situations including other issues like traumatic brain injury, etc.

22. Framing “hearing” in a broader perspective • International perspective broader • Framing these issues within the perspective of the World Health Organization

23. WHO’s International Classification of Functioning, Disability, and Health • Function: What are the target issues? • CORE sets for hearing loss: Broad and looks at function, ability/disability and health • Danermark (2010)

24. Broader perspective related to hearing/listening • Places where cognition may matter more • Traumatic brain injuries: Clearly often have an impact on auditory processing/listening that is well defined…loci and clear symptomology • Mild head injuries/post concussive syndrome: Sequalae are subtle and difficult to assess (Peterson, 2000)

25. Some examples: • Person that has difficult hearing in noise after a head injury • The “dodge ball” incident • Exacerbation of issues: • Family with carbon monoxide issues • Auditory system degradation • Encephalitis

26. Some examples: • Interaction between hearing loss and auditory perceptual issues • Older adult with peripheral hearing loss pre/post stroke • Overlooking MHI and attributing issues to other causes • Post concussive syndrome vs. Meniere’s disease

27. A couple of additional thoughts • Article in Neurology • Described traumatic brain injury as a “hidden epidemic” • “Old” injuries that may have been forgotten—a sports injury, fall, blow to the head that may have seemed “nothing” at the time—may have impact years later • Baby boomers, etc. that are concerned that they have Alzheimer's—notice cognitive and behavioral problems • Often misidentified…points to remember that normal aging changes in the brain can show these changes, which demonstrate notable loss of brain tissue (even with very mild TBI)

28. Patient in our clinic • 33 year old man • Had stroke • Had normal hearing prior to the stroke • Reports that he cannot hear from his right ear (stroke effected left side of body) • Reports that auditory information when noise is present is “lost” for him • Qualitative issues with listening (iPod, etc.) • Has had 2 audiograms in past two months—”normal” hearing bilaterally

29. Role of hearing/listening in the life of the patient • Hearing is assumed and often overlooked…if that’s true for hearing, even more true for listening • Hearing/listening skills are scaffold for other types of information processing (language, attention, pragmatics, etc.) • All of this is wrapped in cognition, as we are learning

30. Continuum as a guide • The “peripheral” and “central” labels are somewhat artificial in terms of addressing functional/behavioral deficits • Often reported difficulties look similar • Audiologists guided by results of audiogram lulled into a false sense of security • Patient leaves with a frustration/embarrassment that “their problem” is all in “their head” • Issues related to location of deficit probably less relevant than deficits resulting from it

31. The Auditory System • Auditory processing skills can be considered on this continuum, however in persons with hearing loss, these issues/skills co-exist with peripheral hearing abilities • Definitions of APD and the role of peripheral hearing loss • Patients with essentially normal peripheral hearing acuity with auditory “complaints”

32. Central auditory nervous system • “…includes all the anatomical and processing mechanisms between the cochlear nucleus in the brainstem to the auditory cortex of the temporal region” • Considerable activity in this area, including auditory memories stored in primary auditory cortex, Heschl’s gyrus and Sylvian fissure as “auditory processing centers”, and left planum temporale as controlling language processing • Bamiou, Musiek, and Luxon (2001) • Broader perspective

33. What IsAuditory Processing? “What we do with what we hear” (Katz) “…umbrella term for all operations executed on peripheral auditory inputs, and which are required for the successful and timely generation of auditory precepts, their resolution, differentiation, and identification.” (Phillips, 2002)

34. Site of Lesion vs. functional issues • History of interest in clinical APD; comes from adults • Bocca and colleagues • Site-of-lesion focused related to technological limitations, etc. • Currently: • Focus on pediatric cases* • Need to address functional behaviors

35. Renewed interest in adults with auditory processing issues due to veterans presenting with these types of deficits in significant number Schneider (personal communication). Grant addressing blast injury in soldiers returning from Iraq Walter Reed Army Medical Center and Portland VA Medical Center (personal communication): Incidence of APD in this population

36. Current concepts • Traumatic brain injury has been labeled as a “signature injury” of the wars of Iraq and Afghanistan • Concerns: Possible long term effect of mild traumatic brain injury or consciousness or altered mental status, as a result of deployment related head injuries, particularly those from proximity to blast explosions (Hoge et al, 2008)

37. Estimate of number of troops with mild TBI • Cited as high as 18% by army medical officials • Persistent post-concussive symptoms including irritability, memory problems, difficulty concentrating, and headache • Significant number of subtle visual, language, and hearing /listening related issues reported (Hoge et al, 2008)

38. Lack of population based studies • No good civilian data • No comparison groups • Question: Would population screening for mild TBI improve health outcomes? (Hoge et al, 2008) • Biases in the medical professions • Ability to generalize: assault injuries, MVA’s, etc. • Interaction between the auditory nervous system and non-auditory factors: cognitive processing

39. Roles of the Central Auditory Nervous System: A functional perspective • “Processing” rapid signals • Gating • Alerting to incoming information • Communication between the two hemispheres of the brain • Coordinating or “teaming” between the two ears--they work as a unit • Again…the CANS designed to address precision in listening

40. Role of the Central Auditory System • …To establish a representation of the speech signal that is then available for perceptual or linguistic elaboration (Phillips, 1998) • Starting to focus on the non-auditory aspects of listening • Again, what patients tell us

41. The concept of redundancy: Internal vs. external • Intrinsic or internal redundancy: Built into the auditory system (both peripheral and central)…multiple representations • Certainly can be impacted by disorder of auditory system, such as tumor, demylinating disease, etc.

42. The concept of redundancy: Internal vs. external • Extrinsic or external redundancy: Built into the signal (syntax, morphology, semantics, etc) which enhance comprehension of the signal • Can be impacted by issues such as cognitive impairment (e.g. Alzheimer’s)

43. Bottom up and top down • In reality, not linear process but co-exist • Not “a one way street” • Thought of as an afferent process • Also need to consider efferent process • EXECUTIVE FUNCTIONING SKILLS

44. Auditory processing: …the efficiency and effectiveness by which the central nervous system (CNS) utilizes auditory information.

45. Neural Plasticity (“Brain Flexibility”) • Neural plasticity: alteration of nerve cells to better conform to immediate environmental influences, with this alteration often associated with behavioral changes • Three types • Developmental • Compensatory (after lesion) • Learning related (Musiek and Berge, 1998)

46. The auditory system is designed to: • Be flexible and fast • Capitalize on it’s own redundancies • Support (“scaffold”) other skills • Operate “automatically” • PREDICTABILITY AND REDUNDANCY

47. Disorders of processing auditory information

48. Bruton Conference (JAAA 2000) Definition of Auditory Processing Disorder(Jerger and Musiek, 2000) An auditory processing disorder (APD) is defined as a deficit in the processing of information in the auditory modality.

49. Auditory Processing Disorders (APD) • An auditory processing disorder (APD) is defined as a deficit in the processing of information in the auditory modality (Jerger and Musiek, 2000)

50. Central Auditory Processing Disorders Defined: A breakdown in auditory abilities resulting in diminished learning (e.g. comprehension) through hearing, even though though peripheral hearing sensitivity is normal