California Academy of Audiology Neurophysiological Effects of Hearing Loss and Hearing Aid Usage on Perceptual and Cognitive Processing in Older Adults Kristina C. Backer, Ph.D. September 7, 2017 California Academy of Audiology

Acknowledgments Kelly Tremblay, Ph.D., CCC-A Kate McClannahan, Au.D., Ph.D. Brain & Behavior Lab Members UW Communication Studies Participant Pool UW Auditory Neuroscience Training Grant * No financial or non-financial COI’s.

The Malleable Brain

??? Central Effects of Central Effects of Peripheral Pathology Reduced Grey Matter Volume in Frontal & Temporal Lobes Degraded Auditory Input to Cortex Declines in Inhibitory Processing Increased Listening Effort Central Effects of Biological Aging (CEBA) Central Effects of Peripheral Pathology (CEPP) (i.e., SNHL) Central Effects of Auditory Stimulation (via HAs) (CEAS) ??? Slowed Processing Speed Reduced Grey Matter Volume in Auditory Cortex Reduced Working Memory Capacity (for a review, see Tremblay & Backer, 2016, Ear and Hearing)

Research Questions Auditory Perception? (Study 1) How do untreated and treated sensorineural hearing loss in older adults affect the neurophysiology underlying: Auditory Perception? (Study 1) Cognitive Processing? (Study 2) EEG

Cross-Sectional Design: 3 Groups of Older Adults Hearing Aids for ≥ 2 years! CEBA (Aging) Normal Hearing (NH) CEBA + CEPP (Aging + HL) Untreated Hearing Loss (u-HL) CEBA + CEPP + CEAS (Aging + HL + HAs) Treated Hearing Loss (t-HL) * All included participants passed the Montreal Cognitive Assessment (MoCA).

Study 1 (Perception) – Older Adult Participants NH Group (n = 12, 66 ± 2 years, 11 females) u-HL Group (n = 12, 67 ± 4 years, 10 females) t-HL Group (n = 12, 68 ± 4 years, 4 females) Selected a subset of the participants tested in each group, in order to age-match the groups!

Study 1 (Perception) – Behavioral Measures Self-Reported Auditory Function: Hearing Handicap Inventory for the Elderly (HHIE) (Ventry & Weinstein, 1982) Speech, Spatial and Qualities of Hearing Scale, abbreviated version (SSQ-12) (Noble et al., 2013) Hearing in Noise Test (HINT) (Nilsson, Soli, & Sullivan, 1994) Verbal Working Memory: Word Auditory Recognition and Recall Measure (WARRM) (Smith, Pichora-Fuller & Alexander, 2016) Reading Span Test (Daneman & Carpenter, 1980)

Results: Self-Reported Auditory Function

Results: Hearing in Noise Test (Unaided) Noise played at 65 dB SPL. Speech level varied.

Results: Working Memory Tested using PTA-based stimulus level.

Auditory Evoked Potentials The P1-N1-P2 complex reflects neural registration of sound at the cortex. Sound Onset Figure from Friesen & Tremblay, 2003. Electrophysiological Measures of Hearing, Speech and Language.

Previous Studies Impact of HL in Older Adults on P1-N1-P2 inconsistent Larger responses (e.g. Alain et al 2014), smaller responses (e.g. Bertoli et al 2005), later responses (Campbell & Sharma 2013), responses unaffected (e.g. Tremblay et al 2003) Tremblay et al (2003) No effect Smaller Bertoli et al (2005) Alain et al (2014) Larger For example, the P1-N1-P2 has been used in older adults, with and without hearing loss. However, results are inconclusive… With the suggestions that larger responses may be related to decreased inhibitory mechanisms coinciding with aging and hearing loss, or that later latency responses represent inefficiency in the system or decreased neural synchrony, or that smaller responses indicate fewer neurons firing or with less synchrony leading to diminished response strength… These differences can be explained somewhat by methodological differences, but, recent studies have implied that the neural registration of sound may be associated/correlated with higher level abilities, such as speech perception in noise, and may be indicators of higher level cognitive changes.

Previous Studies Impact of HL in Older Adults on P1-N1-P2 inconsistent Most previous studies have not accounted for Stimulus Audibility and Hearing Aid experience!

Study 1 – EEG Research Question How do untreated and treated HL in older adults affect the neurophysiology underlying auditory perception (P1-N1-P2)? 2 Sound Presentation Levels: Equal SPL (71 dB) Equal Sensation Level (Individualized) Plasticity due to Sound Deprivation/Stimulation? Or Artifact of Audibility Differences between NH and HL groups?

Study 1 (Perception) – EEG Design

Study 1 (Perception) – EEG Stimulus Levels

Study 1 (Perception) – Predictions Group x Stimulus Level Interaction History of Hearing Loss Group x Stimulus Level Interaction Differences In Stimulus Audibility

Results: P1 Significant Group x Stimulus Level Interaction  Driven by Differences in NH Stimulus Audibility (Similar Interaction for NH vs. t-HL)

Results: P1

Results: N1 Significant Group x Stimulus Level Interaction  Driven by Differences in NH Stimulus Audibility (Similar Interaction for NH vs. t-HL)

Results: N1

However, no significant group differences in P2 observed. Results: P2 Interaction Not Significant  P2 Differences may be due to History of Hearing Loss However, no significant group differences in P2 observed.

Results: P2

What about History of HA Usage? No Significant Differences between u-HL and t-HL groups.

Study 1 (Perception): Interim Summary T-HL participants reported the most self-reported hearing handicap (HHIE) and had the greatest difficulty understanding speech in noise (HINT). But the groups showed similar Working Memory performance. Stimulus Audibility Differences between NH and HL participants affected Auditory Evoked Potentials response patterns (P1-N1). Important to control for audibility! Participants with u-HL and t-HL had similar Auditory Evoked Potentials.

Study 2 – Research Question How do untreated and treated sensorineural hearing loss in older adults affect the neurophysiology underlying cognitive processing? 2 Forms of Cognitive Processing: Preparatory Attention Attention to Memory Auditory and Visual Domains: Modality-Specific or Supra-modal? EEG

Cross-Sectional Design: Older Adults Hearing Aids for ≥ 2 years! All included subjects passed the MoCA. Specifically focusing on Cognitive Processing: 1) Preparatory Attention to External Stimuli 2) Attention to Memory Normal Hearing (NH) Untreated Hearing Loss (u-HL) Treated Hearing Loss (t-HL)

Study 2 (Cognition) – Older Adult Participants NH Group (n = 12, 64 ± 3 years, 10 females) u-HL Group (n = 12, 68 ± 4 years, 8 females) t-HL Group (n = 8, 68 ± 4 years, 2 females)

Result 1: Cognitive Tests NO group differences on: Culture-Fair Intelligence Test (CFIT) (Cattell et al., 1973) tests non-verbal fluid intelligence. Reading Span Test (Daneman & Carpenter, 1980) tests visual verbal working memory (sentences). Word Auditory Recognition and Recall Measure (WARRM) (Smith, Pichora-Fuller & Alexander, 2016) tests auditory verbal working memory (words). Tested using Pocket Talker or personal hearing aids, or PTA-based stimulus level.

Study 2 (Cognition) – EEG Task Preparatory Attention Attention to Memory Remove timing info.

Study 2 (Cognition) – Overview of Task Examine Neural Activity during Preparatory Attention Examine Neural Activity during Attention to Memory Auditory Pre-Cue Auditory Retro-Cue Visual Pre-Cue Visual Retro-Cue Uninformative Cue Trial Uninformative Cue Trial

Result 2: Task Performance - Accuracy Participants Benefited from Pre- and Retro-Cues, BUT No Significant Group Differences.

Result 2: Task Performance – RT Participants Benefited from Pre- and Retro-Cues, BUT No Significant Group Differences.

Neural Oscillations Alpha (~8-13 Hz) Easy to detect alpha power modulations using EEG. Modulations in alpha power reflect selective attention and working memory load. Modulations in alpha power have been observed in similar types of attention/memory tasks. May serve as an objective index of listening effort.

Alpha Power Suppression Effect In other words, “I need to pay attention to this particular stimulus or memory representation, regardless of its sensory modality.” Greater alpha power suppression in response to the Auditory and Visual Cues likely reflects a supra-modal attentional orienting process.

Result 3: Preparatory Attention The two hearing loss groups (u-HL and t-HL) exhibited stronger alpha power modulations than the NH group. +3.5 -3.5 dB

Result 3: Preparatory Attention: Sensory Weighting Model Preliminary Results Visual vs. Uninf. Pre-Cue Visual Auditory Auditory vs. Uninf. Pre-Cue 10 Channels showing the largest modulation of alpha power, averaged across all 3 groups. * One outlier in the u-SNHL group excluded.

Result 4: Attention to Memory No significant group differences. All groups showed similar cue-induced modulations of alpha activity when selectively attending within memory. +4.5 dB -4.5

Result 4: Attention to Memory: Sensory Weighting Model Preliminary Results Visual vs. Uninf. Retro-Cue Visual Auditory Auditory vs. Uninf. Retro-Cue * One outlier in the NH group excluded.

Study 2 (Cognition) – Summary Hearing loss/hearing aid usage did not affect performance on CFIT, Reading Span, WARRM, or the EEG task. Hearing loss/ hearing aid usage did not affect neural activity underlying Attention to Memory. A history of u-HL and t-HL appears to alter the neural mechanisms underlying Preparatory Attention. Thus, both u-HL and t-HL may change the way in which the brain prepares to engage with the external world.

General Conclusion When treating HL, it is important to keep in mind that the ear and brain are linked. Perceptual changes due to untreated or treated HL (e.g., changes in audibility) may in turn affect cognitive aspects of listening, such as effort and how the brain engages with the external world.

Thank you for listening. [Seattle Skyline]