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CI Forum Purdy et al CI research.pptx

  1. 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
  2. Captioning Workshop: NZ Research (SP) Suzanne Purdy Room 731.203 (LC) 03&fs=40 bookingref=GXMG5DZP48203 Live stream:
  3. • 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 Background 3
  4. Topics 1. Auditory evoked potentials 2. Auditory plasticity and training 3. Cognition and speech in noise in people with cochlear implants 4. Processing of speech emotion (‘prosody’) (5 published New Zealand studies)
  5. Recording brain responses to sound: cortical auditory evoked responses 5 http://www.the- The-Sounds-of-Silence/
  6. Recording auditory evoked potentials
  7. 1. Electrophysiological and speech perception measures of auditory processing in experienced adult cochlear implant users AS Kelly, SC Purdy, PR Thorne (2005). Clin Neurophys 116:1235-46. 250 Hz 4 kHz Black = control group Red = ‘better’ CI: sentence scores >85% Blue = ‘poorer’ CI: sentence scores <40% • Age range 27–74 years • CI use 1.3-5.2 years • Nucleus CI–22M • Evoked potentials recorded to tones delivered via loudspeaker P1 N1 P2 P1 N1 P2
  8. 2. Speech scores improve over time 0 20 40 60 80 100 Visit (months) Speech score (%) sentences phonemes words 0 1 3 6 9 Seminars in Hearing Volume 37 (1) · February 2016 CI24 implant users
  9. Evoked potentials improve over time, but with differing time course: 57 year old with congenital hearing loss, profoundly deaf for 10 years. P1 changed very little, N1 reached stable amplitudes at 1 month, P2 increased in amplitude over the 9 months. Switch on 1 month 3 months 6 months 9 months P1 N1 P2
  10. Improvements in P2 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 P2 increase over time for C4 (right hemisphere recording) implant-tattoos-support-his- kids/2991160/
  11. 11 3.
  12. 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)
  13. Speech in noise scores [and spectral (pitch) discrimination] improved after training 13 0 10 20 30 40 50 60 70 80 v1 v2 v3 v4 Easy Noise Hard Noise *
  14. 14 N1-P2 amplitude significantly larger post-training for /baba/ stimulus in quiet Pre training Post training P1 N1 P2 P1 N1 P2
  15. 4. Impact of cognition and noise reduction on speech perception in adults with unilateral cochlear implants Investigators: Suzanne Purdy¹, David Welch2, Ellen Giles², Catherine Morgan3, Renique Tenhagen¹, Abin Kuruvilla-Mathew¹ ¹Speech Science, Faculty of Science, University of Auckland ²Audiology, Faculty of Medical & Health Sciences, University of Auckland 3Cochlear Ltd, Sydney, Australia in press, Cochlear Implants International
  16. What is cognition? cog·ni·tion /kägˈniSHən/ 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
  17. 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)
  18. Listening to speech in noise [effortful listening] depends on hearing and cognition
  19. ash/a/a_07/a_07_p/a_07_ p_tra/a_07_p_tra.html
  20. 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:sup1, 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)
  21. 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 isteningSpan/AutomatedLSPAN.manual
  22. 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.
  23. Questions 1. Does SmartSound iQ (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?
  24. 35 40 45 50 55 60 off on HINT word score (%) Noise reduction p=0.038 Significant improvement in fixed SNR word score with SNR-NR on, independent of cognitive ability & age (N=13) 7% average Improvement
  25. 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
  26. 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: 7 5 6 2 5 3 = 7 5 6 2 5 3 – Backward: 7 5 6 2 5 3 = 3 5 2 6 5 7 – Sequence: 7 5 6 2 5 3 = 2 3 5 5 6 7 • Coding: total number of correct symbols in timed period (processing speed)
  27. 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
  28. Recognising emotion in speech (happy, sad, fearful, angry) 5. International Journal of Audiology 54(7), 444-452, 2015
  29. 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 P2 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
  30. Cognitive load Questions? amudi_Wijayasiri.pdf
  31. Acknowledgements • CI participants • Deafness Research Foundation • Cochlear Ltd • Pindrop Foundation Questions? Email me at
  32. Abstract New Zealand hearing researchers have been investigating outcomes and rehabilitation for adults using cochlear implants since the 1990s. 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.

Hinweis der Redaktion

  1. Fu’s program is CAST - Computer-Assisted Speech Training (CAST) program and CAST is a research tool developed at the House Ear Institute for the purpose of speech perception testing and training. Three commercially available products have been developed for cochlear implant recipients based on the CAST technology: Sound and Beyond (distributed by Cochlear Americas), Hearing Your Life (distributed by Advanced Bionics Corp, a division of Boston Scientific), and Melody Speech T raining Software (distributed by Melody Medical Instruments Corp). The review paper by Fanshawe et al is not restricted to CIs, nevertheless, it is a good review of 13 papers that have evaluated CBAT
  2. 1. Listening in noise is often perceived to be effortful. This is partly because cognitive resources are engaged in separating the target signal from background noise, leaving fewer resources for storage and processing of the content of the message in working memory. 2. Will the SNR NR noise reduction algorithm provide a release of cognitive ability -
  3. Explain TEST SPEECH FROM FRONT NOISE FROM FRONT condition Main effect: when HINT sentences were presented at a fixed SNR, the percentage of words correctly identified was recorded. There was an improvement on word score when noise reduction was on for all the CI recipients. Analysis =repeated measures ANOVA to test whether people improved in hearing ability with the NR feature switched on (mean =52% vs 45%). There was no interaction with digit span or coding . The word score improved independently of cognitive ability. Improvement was statistically significant (p=0.038) There was no interaction with digit span or coding. Meaning The word score improved independently of cognitive ability. This is similar to other studies
  4. Listening task (HINT sentences presented in noise at SRT of 71%) 71% SRT was identified prior to dual task using adaptive 2 down 1 up procedure. Speech and noise both coming from same speaker directly in front of listener Visual task (correct identification of target number in a previous sequence- speed & accuracy) Participant responds Y or N on computer keyboard ( as quickly as possible) to presence of a number in a visual stream of numbers e.g. 3,8,2,9,4 … 8,
  5. Measures of different cognitive abilities so 2 measures treated separately in analysis digit span (WM)& coding tasks (executive function)did not correlate well (r=0.475, p=0.101) Adults were identified in the analysis as those w good WK and poor WK based on their (raw scores on digit span tasks (= cumulative score across DS forward, backward & sequencing) Good The digit span test is primarily a measure of the intactness of your auditory sensory memory. It measures the number of individual sounds you can hold in mind at one time. The examiner reads a string of digits and the patient is required to repeat them back in the same order. We start with short strings of two or three digits, and we increase the length of the string until the patient can no longer repeat them back accurately.