2019 Conference on Implantable Auditory Prostheses
14-19 July 2019
Granlibakken, Lake Tahoe
Page 241
W11: EVALUATION OF A NEW ALGORITHM TO OPTIMIZE AUDIBILITY IN
COCHLEAR IMPLANT RECIPIENTS
Laura K. Holden, Jill B. Firszt, Ruth M. Reeder, Noel Y. Dwyer, Amy L. Stein, Leo M. Litvak
Washington University School of Medicine, St. Louis, MO, USA
Advanced Bionics, LLC, Valencia, CA, USA
Objective: Understanding varying levels of speech is necessary for effective communication in daily
life; moreover, research has demonstrated a positive relation between audibility and speech
understanding for cochlear implant (CI) recipients. Sound-field threshold levels of 20 dB HL across
the frequency range provide CI users an opportunity to understand soft and very soft speech;
however, programming the sound processor to attain good audibility can be time consuming for
audiologists and difficult for some patients. To address these issues, Advanced Bionics (AB)
designed a new algorithm, SoftVoice. The algorithm computes the energy within each frequency
channel independently and suppresses sounds that fall below a pre-determined noise threshold,
thereby removing system noise and improving the audibility of soft speech. The primary objective of
the following studies was to evaluate the efficacy of SoftVoice in optimizing AB CI recipients’ soft
-
speech perception.
Design: Two studies were conducted. Study 1 had two phases, 1A and 1B. Sixteen adult, AB CI
recipients participated in Study 1A. Acute testing was performed in the unilateral CI condition using
a Harmony sound processor programmed with participants’ everyday
-use program (Everyday) and
that same program but with SoftVoice implemented. Speech perception measures were
administered at several presentation levels in quiet (35-60 dB SPL) and at 60 dB SPL in noise. In
Study 1B, ten of the participants compared Everyday and SoftVoice at home to obtain feedback
regarding SoftVoice use in various listening environments. During Study 2, soft-speech perception
was acutely measured with Everyday and SoftVoice for ten participants using the Naida CI
processor. Results with the Harmony (Study 1A) and Naida processors were compared. In addition,
Study 2 evaluated programming options for setting electrode threshold levels (T-levels or Ts) to
improve the usability of SoftVoice in daily life.
Results: Study 1A revealed significantly improved sound-field threshold levels from 250-6000 Hz
with SoftVoice compared to Everyday. Speech perception scores were significantly higher with
SoftVoice than Everyday at soft presentation levels (35, 40, 45 and 50 dB SPL). No significant
differences in scores were found between programs for tests presented at a conversational level (60
dB SPL) in quiet or in noise. After take-home experience with SoftVoice and Everyday (Study 1B),
half of the participants reported a preference for SoftVoice over Everyday; however, six reported
bothersome environmental sound when listening with SoftVoice at home. Results of Study 2
indicated similar soft-speech perception between the Harmony and Naida. Furthermore,
implementing SoftVoice with Ts at the manufacturer’s default setting of 10% of Ms reduced reports
of bothersome sound during take-home experience; however, soft-speech perception was best with
SoftVoice when Ts were behaviorally set above 10% of Ms.
Conclusions: Results indicate that SoftVoice has the potential to be an efficient tool for optimizing
AB CI users’ audibility and in turn, soft
-speech perception. To achieve optimal performance at soft
levels and comfortable use in daily environments, setting T-levels need to be considered with
SoftVoice. Future work should examine program parameters that may benefit soft-speech
perception when used in combination with SoftVoice (e.g., increased input dynamic range).
Funding source: Advanced Bionics, LLC and NIH/NIDCD R01DC009010.