Self-Adjustment of Upper Electrical Stimulation Levels in CI Programming and the Effect on Auditory Functioning

Objectives: With current cochlear implants (CIs), CI recipients achieve
good speech perception in quiet surroundings. However, in acoustically
complex, real-life environments, speech comprehension remains difficult
and sound quality often remains poor. It is, therefore, a challenge
to program CIs for such environments in a clinic. The CI manufacturer
Cochlear Ltd. recently introduced a remote control that enables CI recipients
to alter the upper stimulation levels of their user programs themselves.
In this concept, called remote assistant fitting (RAF), bass and
treble controls can be adjusted by applying a tilt to emphasize either
the low- or high-frequency C-levels, respectively. This concept of selfprogramming
may be able to overcome limitations associated with finetuning
the CI sound processor in a clinic. The aim of this study was to
investigate to what extent CI recipients already accustomed to their clinically
fitted program would adjust the settings in daily life if able to do so.
Additionally, we studied the effects of these changes on auditory functioning
in terms of speech intelligibility (in quiet and in noise), noise tolerance,
and subjectively perceived speech perception and sound quality.
Design: Twenty-two experienced adult CI recipients (implant use >12
months) participated in this prospective clinical study, which used a
within-subject repeated measures design. All participants had phoneme
scores of ≥70% at 65 dB SPL in quiet conditions, and all used a Cochlear
Nucleus CP810 sound processor. Auditory performance was tested by
a speech-in-quiet test, a speech-in-noise test, an acceptable noise level
test, and a questionnaire about perceived auditory functioning, that is,
a speech and sound quality (SSQ-C) questionnaire. The first session
consisted of a baseline test in which the participants used their own CI
program and were instructed on how to use RAF. After the first session,
participants used RAF for 3 weeks at home. After these 3 weeks, the
participants returned to the clinic for auditory functioning tests with their
self-adjusted programs and completed the SSQ-C.
Results: Fifteen participants (68%) adjusted their C-level frequency
profile by more than 5 clinical levels for at least one electrode. Seven
participants preferred a higher contribution of the high frequencies relative
to the low frequencies, while five participants preferred more lowfrequency
stimulation. One-third of the participants adjusted the high
and low frequencies equally, while some participants mainly used the
overall volume to change their settings. Several parts of the SSQ-C questionnaire
scores showed an improvement in perceived auditory functioning
after the subjects used RAF. No significant change was found on
the auditory functioning tests for speech-in-quiet, speech-in-noise, or
acceptable noise level.