2019 Conference on Implantable Auditory Prostheses

14-19 July 2019

Granlibakken, Lake Tahoe

Page 145

M54: COMPARING ANALOG AND PULSATILE STRATEGIES

USING PRIMARILY TEMPORAL INFORMATION

Natalia Stupak, David Landsberger

NYU School of Medicine, new york, NY, USA

Early cochlear implants (CI) used analog stimulation which was eventually replaced with

interleaved pulsatile stimulation to reduce both power consumption and electric field

interactions. However, a sizable proportion of CI users who have had the opportunity to use

both analog and pulsatile strategies prefer the analog strategies. Stupak et al. (2018)

demonstrated that analog stimulation provides different perceptual qualities than pulsatile

stimulation, but what those qualities are is still undetermined. It is possible that analog

stimulation, which might better represent a waveform than pulsatile stimulation, may have an

advantage for encoding temporal information.

In the present study, we implement single-channel analog and pulsatile strategies. This allows

evaluation of performance without useful spectral information or channel interactions. Both

maps were programmed into a body-worn Advanced Bionics Platinum Series Processor (PSP)

using SCLIN software; Analog stimulation was implemented with the SAS strategy, pulsatile

stimulation was implemented with the CIS strategy. In both maps, only electrode 1 was active

and represented a frequency range of about 250-700 Hz. Stimulation for both strategies was in

monopolar mode. Subjects were given a short time to adapt to each strategy by listening and

simultaneously reading along to an audio book for 20 minutes. Afterwards, performance was

evaluated on vowel and consonant identification as well as a pitch direction task (Melodic

Contour Interval; Galvin et al., 2007).

Pilot data has been collected with 2 subjects. Despite the 20 minutes of adaptation,

performance on the vowel task was near chance for both subjects using the pulsatile strategy.

However, using the single-channel analog strategy, one subject remained at chance for vowel

identification while the other was able to identify 32% of vowels

(d’ = 1). Performance was near

chance for both subjects with both strategies for consonant identification. For the MCI task, one

subject performed similarly with both strategies while the other improved noticeably with the

analog strategy. Data with more subjects will be presented.

References:

Galvin III, J. J., Fu, Q. J., & Nogaki, G. (2007). Melodic contour identification by cochlear implant

listeners. Ear and hearing, 28(3), 302.

Stupak, N., Padilla, M., Morse, R. P., & Landsberger, D. M. (2018). Perceptual Differences

Between Low-Frequency Analog and Pulsatile Stimulation as Shown by Single-and

Multidimensional Scaling. Trends in hearing, 22, 2331216518807535.