Cochlear implants: fundamentals and applications

Graeme Clark9780387215501, 9780387955834, 0387955836

The cochlear implant is a device that bypasses a nonfunctional inner ear and stimulates the auditory nerve directly with patterns of electrical currents derived from incoming sounds. The culmination of investigations in many disciplines, it is the first major advance in helping profoundly deaf children communicate since the Sign Language for the Deaf was developed at the Institution des Jeunes Sourds in Paris some 200 years ago. Written by the “father” of the multi-electrode implant, this comprehensive text and reference gives an account of the fundamental principles underlying cochlear implants and their clinical application. It thus discusses research in all relevant disciplines, including: – Surgical anatomy, concentrating on essentials relevant to engineering – Pathology, focusing on the inner ear’s response to the implant and to electrical stimulation – Biophysics and electrochemistry, addressing the interface between electrode and tissue – Neurobiology, with particular emphasis on the issue of safety – Physiology, summarizing current theories of frequency and amplitude coding – Psychophysics, focusing on pitch and loudness perception – Speech science, including phonetics, perception, and language – Electronic principles of signal processing needed for speech perception – Clinical factors of importance to the engineering – Surgical procedures to help scientists and engineers understand the realities for implant development – Communication skills achieved for different speech processing strategies – Socioeconomic and ethical issues For the clinician, the book will provide guidance in the treatment of patients; for the engineer and researcher it will provide the background for further research; and for the student, it will provide a thorough understanding of the subject.

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Table of contents :
Series Preface……Page 8
Preface……Page 10
Acknowledgments……Page 14
Contents……Page 16
Abbreviations……Page 26
Deafness……Page 32
Overall Concept of the Bionic Ear……Page 33
Fundamental Objections and Questions……Page 34
Answers to the Fundamental Objections……Page 35
Eighteenth Century……Page 40
1900 to 1930s: Early Hearing Aids……Page 42
1930s to 1940s: Initial Indirect Electrical Stimulation in the Human……Page 43
1950s to 1960s: Initial Direct Electrical Stimulation in the Human……Page 45
1960s: Fundamental Research in the Experimental Animal……Page 48
1970s: Fundamental Research in the Experimental Animal and Human……Page 51
1980s: Fundamental Research, Industrial Development, and Clinical Trials……Page 62
1990s: Continuing Fundamental Research and Industrial Development……Page 84
References……Page 85
Overview……Page 97
Components……Page 98
Embryology……Page 99
Blood Supply and Innervation……Page 100
Infant and Young Child……Page 101
Pinna……Page 103
Ossicles……Page 104
Muscles……Page 105
Relationships……Page 106
Posterior Tympanotomy……Page 109
Round Window and Niche……Page 110
Osseous……Page 112
Membranous……Page 116
Histology of the Cochlea……Page 118
Embryology……Page 121
Overview……Page 122
Auditory Nerve……Page 125
Cochlear Nucleus……Page 126
Superior Olivary Complex……Page 128
Inferior Colliculus……Page 130
Medial Geniculate Body……Page 131
References……Page 132
Inflammation……Page 139
Pathophysiology……Page 140
Tissue Responses in the Cochlea of the Experimental Animal……Page 143
Tissue Responses in the Human……Page 148
Methods of Investigation……Page 151
Tissue Response……Page 152
Otitis Media……Page 155
Labyrinthitis and Meningitis……Page 156
Experimental Animal Studies……Page 161
Host Factors and Foreign Bodies……Page 175
Clinical Protocol……Page 178
Spiral Ganglion……Page 179
Cochlear Nucleus……Page 180
Pons and Midbrain……Page 181
Human Brainstem……Page 182
Genetic and Chromosomal……Page 183
Acquired……Page 187
References……Page 190
Current and Charge……Page 199
Impedance……Page 200
Charge Transfer……Page 201
Equivalent Circuits……Page 202
Impedance……Page 204
Mechanisms……Page 207
Stimulus Parameters……Page 208
Scanning Electron Microscope Evaluation of Electrodes……Page 210
Electrochemically Safe Stimulus Parameters……Page 211
Biochemical Effects……Page 212
Neural Preservation……Page 213
Acute studies on the Effects of Low Rates of Stimulation……Page 214
Chronic Studies on the Effects of Low Rates of Stimulation……Page 215
Acute Studies on the Effects of High Rates of Stimulation……Page 222
Chronic Studies on the Effects of High Rates of Stimulation……Page 226
Chronic Studies on the Effects of Low Rates of Stimulation……Page 228
References……Page 229
Action Potentials……Page 238
Strength-Duration Curves……Page 241
Electrical Models of the Nerve Membrane……Page 242
Convergence and Divergence……Page 243
Auditory Physiology……Page 244
Physics of Sound……Page 245
External and Middle Ear Function……Page 246
Cochlea……Page 247
Auditory Neurophysiology……Page 250
Mechanisms……Page 272
Electrophonic Hearing and Cochlear Implantation……Page 274
Electrical Stimulation of the Cochlear Nerve……Page 275
Temporal Coding……Page 276
Place Coding……Page 301
Intensity Coding……Page 311
References……Page 313
Acoustic Stimulation……Page 335
Pitch and Timbre……Page 336
Loudness……Page 341
Critical Band and Ratio……Page 344
Musical Acoustics……Page 347
Bilateral Hearing……Page 350
Temporal Information……Page 354
Temporal Information: Prelinguistically Deaf……Page 362
Place Information……Page 365
Place Information: Prelinguistically Deaf……Page 377
Loudness……Page 380
Intensity Information: Prelinguistically Deaf……Page 391
Musical Perception……Page 392
Bimodal Stimulation……Page 395
Bilateral Stimulation……Page 397
References……Page 404
Acoustic……Page 420
Speech Analysis……Page 421
Speech Perception and Production……Page 424
Channel Vocoders and Fixed Filters……Page 434
Formant Vocoders……Page 436
Acoustic Representation of Electrical Stimulation……Page 437
Speech Cues……Page 440
Channel Numbers……Page 441
Channel Selection……Page 443
Electrical Stimulation: Principles……Page 444
Channel Numbers……Page 445
Channel Selection……Page 446
Speech in Noise……Page 447
Speech Processing Strategies……Page 448
Multiple-Channel Strategies: Fixed Filter Schemes……Page 450
Multiple-Electrode Strategies: Formant and Spectral Cue Extraction……Page 454
Adaptive Dynamic Range Optimization (ADRO)……Page 471
Dual Microphones……Page 472
Bimodal Speech Processing……Page 474
Bilateral Speech Processing……Page 477
References……Page 481
8. Engineering……Page 493
Principles……Page 495
Speech Processors……Page 504
Receiver-Stimulators……Page 523
Design Principles……Page 541
Design Realization……Page 557
Conclusion……Page 575
References……Page 576
Adults……Page 589
Children……Page 590
Clinical Protocol……Page 591
History……Page 592
Adults……Page 593
Children……Page 594
Pure Tone Thresholds……Page 598
Impedance Audiometry……Page 601
Hearing Aid Evaluation……Page 602
Cochlear Microphonics and ABR Tests for Neuropathy……Page 603
Speech Perception……Page 605
Language……Page 607
Radiology……Page 608
Electrical Stimulation of the Promontory……Page 611
Vestibular Assessment……Page 613
Hearing and Speech Perception……Page 614
Predictive Factors……Page 615
References……Page 625
Overview……Page 634
Position Multiple Electrodes Close to the Auditory Nerves……Page 635
Fundamentals and Clinical Practice……Page 636
Preoperative Measures……Page 637
Incision……Page 638
Creation of a Bed for the Receiver-Stimulator……Page 642
Creation of Gutter for the Lead Wire Assembly……Page 645
Exposure of the Round Window via a Posterior Tympanotomy……Page 646
Cochleostomy (Opening into the Inner Ear)……Page 647
Insertion of Arrays……Page 651
Sealing the Opening……Page 656
Perilymph “Gusher”……Page 657
Fixing the Electrode Array and Receiver-Stimulator……Page 658
Radiology……Page 659
Intraoperative Complications……Page 660
Postoperative Complications……Page 662
Ossified Cochlea……Page 678
Open Mastoid……Page 681
Transmastoid Labyrinthectomy and Acoustic Neuroma……Page 682
Pedestal (Plug and socket)……Page 683
References……Page 684
Aims……Page 693
Plasticity in the Experimental Animal……Page 694
Plasticity—Psychophysics……Page 695
Analytic Versus Synthetic Training……Page 700
Physiological and Psychophysical Principles……Page 702
Producing a MAP……Page 704
Signal Gain……Page 707
Training in Adults and Children……Page 709
General……Page 710
Predictive Factors……Page 711
Strategy and Time Course for Learning……Page 713
Synthetic……Page 715
Background Noise……Page 716
Telephone……Page 717
Mapping and Fitting Children……Page 718
Conditioning……Page 719
Initial Setting……Page 720
Follow-up Device Settings……Page 721
Neural Response Telemetry……Page 722
Personnel……Page 723
Speech Perception……Page 725
Perception of Environmental Sounds……Page 727
Speech Production……Page 728
Language……Page 729
Acoustic Environment……Page 732
Strategies……Page 733
Program for Implanted Children……Page 734
Counseling of Adults and Children……Page 735
References……Page 736
Development of Tests……Page 746
Variability of Materials and Responses……Page 747
Prerecorded Versus Live Voice……Page 748
Closed-Set Tests……Page 749
Speech Features (Consonants and Vowels)……Page 751
Open-Set Tests……Page 752
Speech Reading……Page 753
Speech Tracking……Page 754
Speech in Noise……Page 755
Test Batteries……Page 756
Bimodal and Bilateral Speech Processing……Page 757
Imitative and Spontaneous Speech……Page 759
Language: Test Principles……Page 760
Expressive Language……Page 761
Predictive Factors……Page 763
Speech-Processing Strategies for Postlinguistically Deaf Adults……Page 765
Speech-Processing Strategies for Pre- and Postlinguistically Deaf Children……Page 777
Nucleus Multiple-Channel (F0/F1/F2) and Multipeak Strategies……Page 783
Receptive Language……Page 786
Expressive Language……Page 789
Cognition……Page 790
References……Page 791
Biological Safety……Page 806
Family……Page 807
Economic Measures……Page 808
Cost-Benefit Analysis……Page 809
Quality of Life……Page 810
Human Experimentation……Page 812
Rights of Children……Page 818
Attitudes of Hearing-Impaired People……Page 821
References……Page 822
Improved Sound Fidelity and Speech Processing……Page 826
Optimal Rate Stimulation……Page 827
Improved Coding……Page 828
Bimodal Speech Processing……Page 834
Improved Speech and Language in Children……Page 836
Totally Implantable Cochlear Prosthesis……Page 840
Auditory Nerve Preservation and Regeneration……Page 841
References……Page 848
A……Page 852
B……Page 853
C……Page 854
E……Page 857
F……Page 858
I……Page 859
L……Page 860
M……Page 861
N……Page 862
P……Page 863
R……Page 864
S……Page 865
T……Page 868
Z……Page 869