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New directions in programming: Choosing frequency allocation tables for postlingually deaf CI users Mario A. Svirsky Dept. of Otolaryngology New York.

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Presentation on theme: "New directions in programming: Choosing frequency allocation tables for postlingually deaf CI users Mario A. Svirsky Dept. of Otolaryngology New York."— Presentation transcript:

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2 New directions in programming: Choosing frequency allocation tables for postlingually deaf CI users Mario A. Svirsky Dept. of Otolaryngology New York University School of Medicine

3 Do postlingually deaf patients adapt completely to the standard frequency allocation tables?

4 Hypotheses 1) Human listeners can adapt to frequency-shifted auditory input, even when theres spectral degradation 2) Some listeners may not adapt completely 3) Individual differences in the ability to adapt completely may have clinical implications and may be addressed by appropriate signal processing.

5 Four methods to measure adaptation to frequency tables 1) Pitch matching 2) Mathematical modeling of vowel identification 3) Perceptual vowel space 4) Self selection of most intelligible frequency table

6 Four methods to measure adaptation to frequency tables 1) Pitch matching 2) Mathematical modeling of vowel identification 3) Perceptual vowel space 4) Self selection of most intelligible frequency table

7 Method 1: Electroacoustic pitch matching Most apical electrode (#22), Nucleus device. Range= Hz Center=250 Hz Postlingually deaf adults with different amounts of post-implant experience. Data from three different laboratories.

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9 Electroacoustic pitch matching- all electrodes Six repetitions per electrode Alternating stimulation to each ear Acoustic frequency adjusted by the listener Randomized starting frequency Acoustic stimuli presented at comfortably loud level (when possible)

10 Chin-Tuan Tan Ben Guo (did not submit picture)

11 Bilateral pitch ranking with very different insertion depths- Case 1 Two Advanced Bionics devices: normal insertion in left ear, only five active electrodes active in right ear (significant bone drillout). Right ear had Ineraid device that was explanted; significant bone growth at the time of reimplantation. Each electrode in the partial insertion ear was pitch ranked 2 to 5 times to each electrode in the full insertion ear. Non-simultaneous presentation Electrode in the full insertion ear was randomized. Similar (standard) frequency tables in both ears. 3 years right; 9 years left.

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13 Right CI: Shallow Left CI: Full Length 479 Hz 1440 Hz 1.7 mm 4 mm Matthew Fitzgerald 2.2 mm

14 Bilateral pitch ranking with very different insertion depths- Case 2 Patient with residual hearing received Hybrid-S 10 mm electrode in the left ear. Two years after the Hybrid implantation she lost residual hearing in both ears and was then implanted with a standard electrode (24 mm) in the right ear. After loss of residual hearing and standard electrode implantation, both processors were programmed with the standard frequency table: Hz. At the time of the Reiss et al. study (Ear and Hearing, 2011) she had 2-3 years of experience with these frequency tables. She was also tested in our laboratory when she had six years of experience with the standard frequency tables in both ears.

15 3760 Hz 325 Hz 3 mm 3760 Hz 325 Hz 7.8 mm 3.9 mm Reiss et al. Ear & Hearing 2011

16 CONCLUSIONS-METHOD 1 Pitch matching Pitch matching did not always line up with frequency allocation table –Electroacoustic pitch matching of most apical electrode, or all electrodes. –Pitch matching across CI ears with different insertion depths. There is significant adaptation, but it is not always complete, despite years of experience.

17 Four methods to measure adaptation to frequency tables 1) Pitch matching 2) Mathematical modeling of vowel identification 3) Perceptual vowel space 4) Self selection of most intelligible frequency table

18 Method 2: Mathematical modeling of vowel identification Mathematical models of vowel confusion data allow us to measure the mismatch between: Places of maximal stimulation along the cochlea for a given vowel Places along the cochlea where the patient expects to be stimulated Qualitative description of Sagi et al (2010)

19 Fu et al. experiment Three postlingually deaf adults users of SPEAK strategy. 4-6 years of experience. Three months of experience with new frequency table Table 1 Table 7 Table 9 CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF CF

20 Fu et al. results

21 Ele c. Freq ElecFreq F2 F1 Sagi E, Fu QJ, Galvin JJ 3rd, Svirsky MA. JARO 2010

22 CONCLUSIONS-METHOD 2 Mathematical modeling CI users show adaptation after they receive a modified frequency allocation table. This adaptation may not be complete even after they reach asymptotic speech perception scores. Correct pitch matching is necessary but not sufficient to achieve complete adaptation.

23 Four methods to measure adaptation to frequency tables 1) Pitch matching 2) Mathematical modeling of vowel identification 3) Perceptual vowel space 4) Self selection of most intelligible frequency table

24 Method 3: Perceptual vowel space A case of complete adaptation and a case of incomplete adaptation to standard frequency tables. Perceptual vowel space data from one of the asymmetric insertion patients

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43 CONCLUSIONS-METHOD 3 Perceptual vowel space Some listeners adapt completely to the standard frequency tables; others dont. A similar statement can be made about different ears for the same listener.

44 Four methods to measure adaptation to frequency tables 1) Pitch matching 2) Mathematical modeling of vowel identification 3) Perceptual vowel space 4) Self selection of most intelligible frequency table

45 Current Clinical Practice Is this optimal? For postlingually deaf patients, probably not. We give every cochlear implant patient the same frequency-to- electrode map.

46 Current Surgical Practice

47 Cochleas come in different sizes Hardy (1938)- cochlear size can vary by as much as 40%. Stakhovskaya et al. (2007): SGN frequency map. –24 mm from the base 76 Hz in a 28 mm cochlea 1,020 Hz in a 42 mm cochlea –10 mm from the base 3,450 Hz 6,100 Hz

48 COCHLEAS COME IN DIFFERENT SIZES Average basilar membrane length is about 35 mm, but it can range from 28 mm to 42 mm. Estimated CF of SG cells in a cochlea of length= Distance from base L=28 mm L=42 mm 24 mm76 Hz1020 Hz 10 mm3450 Hz6100 Hz

49 Evidence suggesting one size does not fit all (frequency tables) Skinner et al. (2002)- correlation between insertion depth and speech perception. Kos et al. (2007), Gani et al. (2007), Shapiro, Roland, Waltzman (2007)- overinsertion, electrode deactivation, too much bass.

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51 Basic idea: power to the patient (or to the audiologist) Selection of frequency-to-electrode maps may be done in real time while the patient turns a knob to maximize the intelligibility of running speech. This real-time tool may allow: –Faster comparison of different maps –Better comparison

52 NEW PARADIGM We have developed PC-based fitting methods that allow very quick (or even real-time) adjustment of frequency maps. This system can be used with cochlear implant users, or with simulations for normal hearing listeners.

53 Change blindness demo

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56 Method 4: Self selection of most intelligible frequency table Listeners are asked to select the frequency table that makes speech sound most intelligible. Assumption: when a listener has adapted completely, he selects his everyday frequency table. Two methods: RTStream for Advanced Bionics patients and Gridstream for Nucleus patients.

57 REAL TIME SPEECH PROCESSING SYSTEM Adam Kaiser, MD Mehmet Aras Mohamed El-Sharkawy, PhD Ben Stelle Shivank Sinha Tasnim Morbiwala Ravi Rayala Megha Daga Chin-Tuan Tan, PhD Mario Svirsky, PhD Technical assistance and equipment from Advanced Bionics (Abhijit Kulkarni) and Cochlear Americas (Chris van den Honert).

58 RTStream- real time selection of frequency maps Total frequency range audible by humans Active filter bank

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60 Frequency table parameters change depending on which square is selected. Self-selection of most intelligible frequency table-2

61 Subject #1 74yo M with hearing loss of unknown etiology, having used a CI for 14 months prior to testing Comfortably auditioned maps Selected one equivalent to the standard map he had been using for years

62 Subject #2 74yo F with hearing loss of unknown etiology, using a CI for 23 months prior Also quickly explored the 2D space Selected a map similar, but different from her standard map

63 Subjects #3, 4, 5

64 FREQUENCY TABLE SELECTION The player lost a shoe Sounds very high pitched shoe sounds like sue and the pis not there The sh is pretty good here but not the best ,000 Thats a REAL sh! This may be the clearest, may be the first choice Svirsky et al., 2011

65 NULL HYPOTHESIS: complete adaptation

66 Self-selected frequency tables for users of the Nucleus device

67 Self-selected frequency tables for users of the Advanced Bionics device

68 ACUTE CHANGE IN SPEECH PERCEPTION SCORES

69 CONCLUSIONS-METHOD 4 Self selection of most intelligible frequency table CI users can comfortably self select their preferred frequency to electrode table. For about half of them, this table is different from the standard frequency table, again suggesting incomplete adaptation in these listeners. Even in an acute setting, self selected maps may allow better speech perception for some CI users (2 or 4 out of 13). Adaptation to the standard frequency tables may be more difficult in cases of insertions that are either too deep or too shallow.

70 A few case studies of adaptation (or lack thereof) to frequency allocation tables 1)Reimplantation of Hybrid-S users 2)Asymmetric electrode insertion across ears 3)Excessively deep insertion

71 1) SPEECH PERCEPTION IN HYBRID PATIENTS REIMPLANTED WITH A STANDARD ELECTRODE

72 2) SPEECH PERCEPTION IN PATIENTS WITH STRONGLY ASSYMETRIC ELECTRODE INSERTION

73 ACUTE CHANGE IN SPEECH PERCEPTION SCORES

74 Electrode 1 initial surgery Electrode 1 regular placement High frequencies 3) EXCESSIVELY DEEP INSERTION?

75 Electrode 1 regular placement High frequencies William Shapiro J. Thomas Roland, Jr.

76 3) EXCESSIVELY DEEP INSERTION?

77 Overall Conclusions Taken together, data obtained with four different methods suggest that postlingually deaf CI users have a remarkable ability to adapt to a given frequency allocation table. However, adaptation may be not always be complete, depending on the interplay between frequency range, insertion depth and cochlear size.

78 Overall conclusions Self selection of frequency tables (and possibly other parameters) is clinically feasible and may be beneficial for some patients.

79 SOME QUESTIONS Who adapts completely and who doesnt? Why do some patients fail to achieve complete adaptation? Is there something we can do about it?

80 Are placed in the cochlear nucleus Are used for patients with a compromised auditory nerve (e.g., NF2) Auditory Brainstem Implants

81 Kanowitz et al., 2004 ABI surface electrode

82 ABI do help speechreading Schwarz et al., 2008

83 In non-NF2 patients, ABI provides open-set speech understanding Colletti and Shannon, 2005

84 QUESTIONS ABOUT ABIs Why do ABI users with NF2 do so much worse that cochlear implant users? Why do non-tumor ABI users do so much better than NF2 ABI users? Why do children with ABIs do so poorly (not shown)?

85 FINAL COMMENTS Clinical interest : successful replacement of a human sense. Scientific interest: platform to answer basic questions about human communication. Translational and multidisciplinary research. Many unanswered questions.

86 Acknowledgments This work has been supported by NIDCD (PIs: Chin- Tuan Tan, Matthew Fitzgerald, Arlene Neuman, Mario Svirsky), NIDRR (PI: Elad Sagi) and the AAO-HNS (PI: D. Jethanamest). Cochlear Americas and Advanced Bionics have loaned equipment, software, and provided technical advice to this project. We also acknowledge the invaluable assistance of NYUs Cochlear Implant Center, its Co-Directors J. Thomas Roland, MD and Susan B. Waltzman, PhD, its chief audiologist, William Shapiro, AuD, and the staff.

87 Acknowledgments This work has been supported by NIDCD (PIs: Chin- Tuan Tan, Matthew Fitzgerald, Arlene Neuman, Mario Svirsky), NIDRR (PI: Elad Sagi) and the AAO-HNS (PI: D. Jethanamest). Cochlear Americas and Advanced Bionics have loaned equipment, software, and provided technical advice to this project. We also acknowledge the invaluable assistance of NYUs Cochlear Implant Center, its Co-Directors J. Thomas Roland, MD and Susan B. Waltzman, PhD, its chief audiologist, William Shapiro, AuD, and the staff. Arlene Susan Neuman Waltzman

88 Acknowledgments The tools for selection of frequency allocation tables described here are patented. The author has not received any royalties from this IP and has pledged to his university that any future royalties will be donated to charity, to avoid conflicts of interest.

89 The end

90 From Reiss et al. Ear & Hearing 2011

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