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IEEE SIGNAL PROCESSING MAGAZINE [76] MARCH 2015

detection. Furthermore, experience with the strategies did not

seem to play a significant role. For some psychophysical measures

differences were observed, but with varying results for HiRes120.

Further research is needed to investigate the impact on more eco-

logically relevant outcome measures.

For all CI sound processing strategies, the information

throughput at the electrode-neural interface may be a fundamental

limitation restricting improvements in perceptual performance.

The limited perceptual effects of introducing explicit information

about the fine structure of acoustic signals in some CI sound pro-

cessing schemes such as HiRes120 and FSP may be a consequence

of this “bottleneck” at the electrode-neural interface. In particular,

if the spatial extent of the neural population activated by each elec-

trode is broad and the populations associated with each electrode

[FIG6] (a) Waveform, (d) spectrogram, and (b)–(c) and (e)–(i) electrodograms of the sentence ”A boy fell from the window” from the

HINT corpus, uttered by a male speaker, but with noise added at an SNR of 10dB.

–1

6,400

3,200

Frequency (Hz)Magnitude + Electrode

1,600

800

400

200

100

Relative Magnitude

Frequency (Hz)Magnitude + Electrode Relative Magnitude

–2

0 0.5 1

Waveform MP3000 EE

1.5 0 0.5 1 1.50 0.5 1 1.5

0 0.5 1 1.5 0 0.5 1 1.50 0.5 1 1.5

ACESpectrogram F0mod

HiRes120CIS-22ch FSP

Time (s) Time (s) Time (s)

(g) (h) (i)

(d) (e) (f)

(a) (b) (c)

“A Boy Fell from the Window”

a boy fell from the window

A Boy Fell From theWindow

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