Peter S Roland M.D. UTSouthwestern Medical Center Dallas, Texas Developments

Transcription

1 Peter S Roland M.D. UTSouthwestern Medical Center Dallas, Texas Developments New electrodes New speech processing strategies Bilateral implants Hybrid implants ABI in Kids MRI vs CT Meningitis Totally implantable devices.

2 Emily Profound SN hearing loss Hearing aids 6 months Nucleus 18 months Nucleus /2 yrs old Now 8 1/2 yrs old Emily Pre op

3 Emily Post op CI audio Post-op CI electric thresholds Pre-op acoustic thresholds w hearing aids Emily

4 What Are the (Remaining) Problems? Wide range of outcomes Speech perception in noise Sound localization Reception of signals more complex than speech, e.g., music High effort in listening for the great majority of patients Remaining Problems Problem Wide range of outcomes Speech reception in noise Sound localization Music reception High effort in listening Approach Identify factors related to outcomes; apply that knowledge in the design of training procedures, refined fittings, or better processing strategies Combined EAS; bilateral implants; closer mimicking of processing in the normal cochlea* bilateral implants; representation of temporal fine structure Representation of temporal fine structure ; closer mimicking of processing in the normal cochlea Combined EAS; bilateral implants; closer mimicking of processing in the normal cochlea *See Wilson et al., "Cochlear implants: Some likely next steps," Annu. Rev. Biomed. Eng. 5: 7-249, 3. See Smith et al., "Chimaeric sounds reveal dichotomies in auditory perception," Nature 416: 87-9, 2.

5 Improved Representation of Acoustic signal Improve temporal fine structure Higher stimulation rates Increase number of channels Real or virtual Must control channel interaction

6 HiResolution Processing (2) Increased Temporal Resolution (8 Hz to 5 Hz) Conventional Strategy HiRes Strategy Input Signal: Vowel er Input Signal: Vowel er Channel 2 Envelope Detector: 25 Hz Channel 2 Envelope Detector: HiRes Electrode: 2 Stimulation Rate: 18 Hz Electrode: 2 Stimulation Rate: 58 Hz ms Envelope Detector Removes Fine Structure ms Looks very similar to direct measurements Of neural firing recorded in animals Fine Structure TM (Fine Frequency TM ) Simulations by Blake Wilson, RTI Speech Speech in Noise (+5 db S/N) Music 6 channels env only FS only both

7 3-Month Conventional (SAS, CIS or MPS) vs. 3-Month HiRes (CIS, 2.8 to 5.6 k pulse/s/channel, 8-16 stimulus channels) -- Mean Scores for First 51 Patients* 1% Preoperative 3 Month Conventional 3 Month HiRes 8% 76% 84% 69% 8% Percent Correct % % 41% 5% 47% 61% % % 21% 12% 3% 3% CNC Words CID Sentences HINT in Quiet HINT +1 db SNR Mean change from conventional to HiRes statistically significant on all tests *Reproduced with permission from Osberger et al., 2 Speech test scores for a CIS user and for 6 subjects with normal hearing (Wilson and Dorman, in prep.) 1 HR4 6 normals 8 Percent Correct CNC CUNY HINT AzBio Cons Vowels CUNY+1 Az+1 Az+5 Test CIS parameters: 16 channels of processing and stimulation; 1449 pulses/s/channel; 11 µs/phase pulses; Clarion CII implant system

8 Advantages of bilateral CIs Improved speech perception in noise Sound localization Assurance that better hearing ear is implanted Preserve neural elements Less fatigue Offeciers E et al Acta Oto-laryngol 5; Laszig R et al Oto & Neuroto 4; Stark et al Cochlear Implants 2; Tyler et al Ear Hear 2

9 Disadvantages of Bilateral CIs Compromise second ear Cost Increased surgical risk Data from the Würzburg Team, Individual Subjects 1 Sentences, Noise Right Sentences, Noise Left Monosyllabic Words, No Noise 8 Subjects Percent Correct right both left right both left Implant(s) right both left

10 What is a Hybrid device? Uses residual, natural hearing together with a CI to replace missing high tones I.E., both electrical and acoustical stimulation A hearing aid is often used in the same ear as the cochlear implant Residual hearing must be preserved

11 Potential advantages of hybrid device More natural sound Much improved speech understanding, especially in noise Much improved tone discrimination and music appreciation Two approaches Med-El mm electrode 3 insertion More trauma? Cochlear 1mm electrode Basil end of basil turn Less trauma?

12 Indications Hearing Threshold (db HL) (ANSI ) Frequency (Hz) Hearing Threshold (db HL) (ANSI ) Frequency (Hz) Convention implant criteria EAS implant criteria Audiometric Results Initial Activation Hearing Threshold (db HL) (ANSI ) Median Unaided Audiometric Data 1 mm Subjects (N=31) Frequency (Hz) Preoperative Initial Activation Median Pre- to Post Diferences Overall Median LF (.125-1k Hz) Shift = 1 db

13 Subj Acoust Resid 1 Electric only Electric + Acoustic Acoustic only C1 (ME14) contra good Percent Correct 8 I (ME6) ipsi good Percent Correct 1 8 cons,quiet cons,+5db CUNY,+1dB CUNY,+5dB X Data C2 (SR3) contra poor Percent Correct 1 8 cons,quiet cons,+5db CUNY,+1dB CUNY,+5dB X Data male cons quiet male cons +5 db CUNY +1 db CUNY +5 db Speech Recognition in Multiple Talker Babble 15 1 SRT-in Babble (db) db N=13 Long-Electrode Short-Electrode Normal Group Courtesy Chris Turner, PhD Univ. of Iowa

14 CNC word scores for 1 mm patients [redrawn from Gantz et al. (5)] Percent correct HA AU pre-imp CI only CI + HA AU 72% correct Percent correct CNC word scores for mm patients (n=13) [redrawn from Kiefer et al. (3)] HA AU pre-imp CI only CI + HA AU Percent correct Sentences at +1 db SNR (n=1) [redrawn from Kiefer et al. (3)] HA pre-imp CI only CI + HA AU

15 Sentences +1 db SNR Percent Correct Conventional E+A HA (ave. & above)

16 Percent Correct CNC word recognition E m E E m A E b EAS binaural implants contralateral EAS Conditions Percent Correct CNC word recognition E m E E m A E b EAS binaural implants contralateral EAS Conditions

17 Full insertion with preservation of ipsilateral residual hearing CNC words Consonants Vowels Percent correct Acoustic Electric A + E Percent correct Acoustic Electric A + E Percent correct Acoustic Electric A + E Condition Condition Condition AzBio Quiet +1 db Percent correct Acoustic Electric A + E Percent correct Acoustic Electric A + E Condition Condition Melody Recognition NH (N=17) SE (N=5) LE (N=27) HiRes (N=7) Percent Correct Courtesy Kate Gfeller, PhD, University of Iowa

18 COCHLEOSTOMY Minimal trauma ass with cochleostomy placement Visibility and landmarks that guarantee that the cochleostomy enters the middle of ST below the BM/SL Ability to use an angle of insertion that minimizes intra cochlear trauma An approach that all surgeons can learn & be comfortable with

19 Absent Cochlear Nerve (L) Dr. Roland R L

20 Early Ossification

21 Meningitis after CI Reefhuis et al NEJM 3 Incidence:.6 in children implanted < 6 yo 23% had meningitis pre-op 11.5% had labyrinthine dysplasia Suzuki et al Arch Oto 1998 T-bone: Mondini meningitis from non-implant ear Recommendations Prompt treatment of children with cochlear implants remains important beyond 2 years after implantation, especially in children with positioners Vaccination recommendations for all implant recipients and for potential implant patients continue to apply OUTCOME Reopens discussion: explantation of the positioner (with or without replacement of the electrode)

22 Should children undergo surgery to remove positioner? Removal of positioner Positive outcome Decrease risk of meningitis Maintain function HOWEVER: Removal of positioner Negative outcome Increase risk of meningitis Decrease function COCHLEAR IMPLANTS & MENINGITIS Risk is highest immediately after implantation Risk increases with cochlear trauma Following re-implantation decrease in implant performance does occur Incidence of meningitis decreases over time following implantation (no reported incidence of meningitis in patients 48 months post implantation)

23 ABI in Children 3 month old profound HL (Kabuki syndrome)

24 ABI in Children Axial HRCT ABI in Children ssssssss

25 ABI in Children Dr. Luxford Vittorio Colletti, MD (Verona, IT) 16 non-tumor children 1 auditory nerve aplasia 2 complete ossification 2 incomplete partition 1 common cavity 1 labyrinthine fracture No complications Good results but little published speech data

26 Problems to be worked out 1) Microphone Technology 1) Sensitivity and freq response 2) Head conducted sound 3) directionality Problems to be worked out 1) Battery performance 1) Time/charge 2) Time to charge 3) Life in years 4) Number of charges

27 Problems to be worked out 1) Hazards 1) Catastrophic battery failure 2) Electronic failure Problems to be worked out 1) Other 1) Compatibility 1) Future upgrade 2) MRI compatibility 3) Price Bottom line: Maybe in about 3 years!