Page 56 - Spring 2019
P. 56

The Flernarkahle Cochlear Implant * ,
A Snapshot: of the History §.> ‘pi, i
The courage of the pioneers made the
modem CI Possible" They persevered Fitter BandEnveInpe compression Madulalian
in the face of vociferous criticism, and _
foremost among them was William F. E ®j’ EH
House, MD, DDS, who with engineer - - - l o
Iack Urban and others developed devic- ~ - 0 ~
es in the late 1960s and early 1970s that g ' ' ' ' '
could be used by patients in their daily ' ' ' ' '
lives outside the laboratory. Addition- %:—> EL-n
ally, the devices provided an awareness
of environmental sounds, were a help- :'] 
ful adjunct to lipreading, and provided
limited recognition of speech with the Figure 1. Block diagram of the continuous interleaved sampling (CIS) processing
restored hearing alone in rare cases‘ "Dr strategy for cochlear implants. Circles with “x,” multiplier blocks; green lines, car-
Bill-» also developed surgical approaches rier waveforms. Band envelopes can be derived in multiple ways and only one way
for placing the Cl safelv in the cochlea is shown. Inset: X-ray image of the implanted cochlea showing the electrode array in
and multiple other surgical inpowtions, the scala tympani. Each channel of processing includes a band-pass filter (BPF); an
described in his inspiring book (House) envelope detector, implemented here with a rectifier (Rect.) followed by a low-pass
will House took most of the arrows filter (LPF); a nonlinear mapping function, and the multiplier. The output of each
from the critics and without his perse_ channel is directed to intracochlear electrodes, EL-1 through EL-n, where n is the
verance, the development of the mod_ number of channels. The channel inputs are preceded by a high-pass preemphasis
ern Cl would have been greatlv delaved filter (Pre-emp.) to attenuate the strong components at low frequencies in speech,
if not abandoned‘ He is universally ac_ music, and other sounds. Block diagram modified from Wilson et al. (1991), with
lmowledged as the "Father of Neurotol_ permission; inset from Hu'ttenbrink et al. (2002), with permission.
ogy,” and his towering contributions are  
lovingly recalled by Laurie S. Eisenberg
(2015), who worked closely with him beginning in 1976 and Step 1 was taken by scientist Andre Djourno and physician
for well over a decade thereafter and stayed in touch with him Charle Eyries working together in Paris in 1957 (Seitz, 2002)
until his death in 2012. and step 5 was taken by Christoph von Ilberg in Frankfurt,
_ _ Ioachim Miiller in Wiirzburg, and others in the late 1990s
I“ my "W" five large Step‘ f°'W“’d led 1° the dmc“ ""1 and early 2000s (von Ilberg et al., 1999; Miiller et al., 2002;
treatment modalities we have today. Those steps are Wilson and Dorman zoos) Bin Home was . .1 _
_ _ _ , . pru-nari y re
(1)proof-of-concept demonstrations thatavarietyofaudi- sponsibie for Step 2, and the first unpimt operation Pep
tory sensations could be elicited with electrical sti.rnulation formed by him was in 1961- Much more information about
ofthe auditory nerve "1 deafpersonsl the history is given by Wilson and Dorman (2008, 2018a),
(2) the development of devices that were safe and could Zeng er at (2008)) and Zmg and Cmion (2015)
function reliably for many years;
(3) the development of devices that could provide multiple A Breakthrough Pruceeeing Strategy
sites of sti.rnulation in the cochlea to take advantage of the Among the five steps, members of the Acoustical Society of
tonotopic (frequency) organization of the cochlea and as- America (ASA) may be most interested in step 4, the discov-
cending auditory pathways in the brain; ery and development of highly effective processing strategies.
(4) the discovery and development of processing strategies A block diagram of the first of those strategies and the pro-
that utilized the multiple sites far better than before; and genitor of many of the strategies that followed, is presented
(5) stimulation in addition to that provided by a unilat- in Figure 1. The strategy is disarmingly simple and is much
eral CI, with an additional CI on the opposite side or with simpler than most of its predecessors that included complex
acoustic stimulation in conjunction with the unilateral CI. analyses of the input sounds to extract and then represent se-
This list is adapted from a list presented by Wilson (2015). lected features of speech sounds that were judged to be most
:4 1 AI:uuII:I:I Tbday 1 Spring 2019

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