Breaking the Sounds of Silence Adult Cochlear Implant

Breaking the Sounds of Silence Adult Cochlear Implant Forum 11 March 2017 Cochlear Implant Research in New Zealand (45 minutes): 1. 45 -2. 30 pm, 2. 45 -3. 30 pm, 3. 45 -4. 30 pm Suzanne C Purdy Speech Science School of Psychology

Captioning Workshop: NZ Research (SP) Suzanne Purdy Room 731. 203 (LC) http: //captioningstudio. com/live/? bookingref=GXMG 5 DZP 482 03&fs=40 bookingref=GXMG 5 DZP 48203 Live stream: https: //auckland. zoom. us/j/828466835

Background • Improvements in speech perception over time are well documented for cochlear implant users • Most improvement occurs within a short time after cochlear implantation in adults • Some studies show a plateau in performance after several years • Auditory evoked potentials (brain responses to sound) are of interest as they provide an objective measure of auditory brain change • Some evoked potential measures, especially cortical evoked potentials, correlate with performance 3

Topics 1. 2. 3. 4. Auditory evoked potentials Auditory plasticity and training Cognition and speech in noise in people with cochlear implants Processing of speech emotion (‘prosody’) (5 published New Zealand studies)

Recording brain responses to sound: cortical auditory evoked responses http: //www. thescientist. com/? articles. view/article. No/43843/title/ The-Sounds-of-Silence/ 5

Recording auditory evoked potentials http: //images. slideplayer. com/11/3189898/slides/slide_3. jpg

1. Electrophysiological and speech perception measures of auditory processing in experienced adult cochlear implant users P 2 P 1 250 Hz N 1 AS Kelly, SC Purdy, PR Thorne (2005). Clin Neurophys 116: 1235 -46. • • Age range 27– 74 years CI use 1. 3 -5. 2 years Nucleus CI– 22 M Evoked potentials recorded to tones delivered via loudspeaker P 2 P 1 4 k. Hz N 1 Black = control group Red = ‘better’ CI: sentence scores >85% Blue = ‘poorer’ CI: sentence scores <40%

2. Speech scores improve over time CI 24 implant users Seminars in Hearing Volume 37 (1) · February 2016

Evoked potentials improve over time, but with differing time course: 57 year old with congenital hearing loss, profoundly deaf for 10 years. P 1 changed very little, N 1 reached stable amplitudes at 1 month, P 2 increased in amplitude over the 9 months. P 2 P 1 Switch on 1 month 3 months 6 months 9 months N 1

Improvements in P 2 area over the five visits • no change for most electrode locations over first 6 months • 8 of the 10 people had right ear implants • steady P 2 increase over time for C 4 (right hemisphere recording) https: //www. sunshinecoastdaily. co m. au/news/dad-gets-cochlearimplant-tattoos-support-hiskids/2991160/

3. http: //aja. pubs. asha. org/article. aspx? articleid=2573094 11

Auditory training is a way to reduce variability in CI outcomes – Sound and Beyond (Cochlear) – Hearing for Life (Advanced Bionics) – only a few independent studies have trialed these programs independently from the developers (Fu et al. , 2007 & Stacey et al. , 2010)

Speech in noise scores [and spectral (pitch) discrimination] improved after training 80 70 Easy Noise Hard Noise * 60 50 40 30 20 10 0 v 1 13 v 2 v 3 v 4

N 1 -P 2 amplitude significantly larger post-training for /baba/ stimulus in quiet Pre training Post training P 2 P 1 N 1 14 P 2 P 1 N 1

4. Impact of cognition and noise reduction on speech perception in adults with unilateral cochlear implants Investigators: Suzanne Purdy¹, David Welch 2, Ellen Giles², Catherine Morgan 3, Renique Tenhagen¹, Abin Kuruvilla. Mathew¹ ¹Speech Science, Faculty of Science, University of Auckland ²Audiology, Faculty of Medical & Health Sciences, University of Auckland 3 Cochlear Ltd, Sydney, Australia in press, Cochlear Implants International

What is cognition? cog·ni·tion /kägˈni. SHən/ Noun 1. The mental action or process of acquiring knowledge and understanding through thought, experience, and the senses. 2. A result of this; a perception, sensation, or intuition. Synonyms knowledge – cognizance – acquaintance http: //www. mcgill. ca/cogsci/

Cognitive processes • Executive function (“involved in complex cognitions, such as solving novel problems, modifying behaviour in the light of new information, generating strategies or sequencing complex actions” Elliot 2003 p. 50) • Memory • Attention Reference: R. Elliot. Executive functions & their disorders. British Medical Bulletin 2003; 65: 49– 59)

Listening to speech in noise [effortful listening] depends on hearing and cognition http: //www. brainvolts. northwestern. edu/projects/speechinnoise/index. php

http: //thebrain. mcgill. ca/fl ash/a/a_07_p/a_07_ p_tra/a_07_p_tra. html

Links between cognition and speech perception with hearing aids • Thomas Lunner (2003) Cognitive function in relation to hearing aid use. International Journal of Audiology, 42: sup 1, 49 -58. • Thomas Lunner, Mary Rudner, Jerker Rönnberg (2009). Cognition and hearing aids. Scandinavian Journal of Psychology, 50, 395– 403 • Reading span task – process & retain information simultaneously • Working memory capacity measured by the reading span test influenced speech recognition thresholds in 72 new hearing aid users (40% of variance)

Reading span correlated with speech perception in noise in new hearing aid users Participants listen to sequences of letters that need to be recalled at the end Each letter in the sequence is preceded by an auditory semantic categorization test – sentence makes sense? yes or no? Letter recall is tested by asking participants to select letters they have already seen from a provided letter matrix http: //www. millisecond. com/download/library/v 5/L istening. Span/Automated. LSPAN. manual

Processing sentences • The host greeted all the guests and asked them to sit at the {table | sky}. • John never liked {crowds | chocolate} and that is why he now lives in the country. http: //www. pitt. edu/~tol 7/research/psych-tests/rspan/

Questions 1. Does Smart. Sound i. Q (SNR-NR) noise reduction algorithm improve speech perception and decrease listening effort for CI recipients listening to speech in noise? 2. What is the ability of people with poorer or better cognitive ability to benefit from the noise reduction?

Significant improvement in fixed SNR word score with SNR-NR on, independent of cognitive ability & age (N=13) 60 p=0. 038 HINT word score (%) 55 50 45 40 35 off on Noise reduction 7% average Improvement

Dual task • Primary listening task (repeat sentences in noise) • Secondary visual task – correct identification of a number in a visual stream of numbers – speed & accuracy measured Signal+Noise

Cognitive ability measured using Weschler Adult Intelligence Scale Fourth Edition (WAIS-IV Wechsler, 2008) • Auditory digit span: forwards, backwards, sequencing (working memory), for example – Forward: – Backward: – Sequence: 756253=756253=352657 756253=235567 • Coding: total number of correct symbols in timed period (processing speed)

Good vs. poor working memory • Trend for scores to be better with noise reduction ON for those with better with working memory during dual task • No difference in speech scores with noise reduction ON vs. OFF for those with poorer working memory

5. Recognising emotion in speech (happy, sad, fearful, angry) International Journal of Audiology 54(7), 444 -452, 2015

Key points • Speech perception with a CI varies but improves with experience and with training • Brain responses to sound reflect auditory deprivation and can change over time with a CI (brain ‘plasticity’) • Some brain responses correlate with performance but this differs across studies • Improved auditory attention and/or pitch perception could mediate improved P 2 evoked responses • Working memory may influence speech perception scores and interact with CI processing (further research underway) • Perception of emotion in speech may be challenging – this could add to listening effort

Cognitive load Questions? http: //www. fitwise. co. uk/files/9314/6356/5133/Pr amudi_Wijayasiri. pdf

Acknowledgements • • CI participants Deafness Research Foundation Cochlear Ltd Pindrop Foundation Questions? Email me at sc. purdy@auckland. ac. nz

Abstract New Zealand hearing researchers have been investigating outcomes and rehabilitation for adults using cochlear implants since the 1990 s. This presentation will talk about findings of some of this research, including variable speech perception outcomes for adults and factors contributing to this. Changes in the auditory brain have been shown using auditory evoked potentials (electrical activity from the brain in response to sound that can be measured with sensors on the scalp). Brain changes occur within a short time after an adult receives a cochlear implant and continue over an extended period. Recent research has shown that adults who have used their implants for a long time can still benefit from auditory training and noise reduction in the cochlear implant improves speech outcomes but this may depend on cognitive factors such as memory.