Background: Although we always want to select the best signal-processing strategy for our hearing-aid
and cochlear-implant patients, no efficient and valid procedure is available. Comparisons
in the office are without listening experience, and short-term take-home trials are
likely influenced by the order of strategies tried.
Purpose: The purpose of this study was to evaluate a new procedure for comparing signal-processing
strategies whereby patients listen with one strategy one day and another strategy
the next day. They continue this daily comparison for several weeks. We determined
(1) if differences existed between strategies without prior listening experience and
(2) if performance differences (or lack there of) obtained at the first listening
experience are consistent with performance after two to three months of alternating
between strategies on a daily basis (equal listening experience).
Research Design: Eight subjects were tested pretrial with a vowel, sentence, and spondee recognition
test, a localization task, and a quality rating test. They were required to listen
to one of two different signal processing strategies alternating between strategies
on a daily basis. After one to three months of listening, subjects returned for follow-up
testing. Additionally, subjects were asked to make daily ratings and comments in a
diary.
Results: Pre-trial (no previous listening experience), a clear trend favoring one strategy
was observed in four subjects. Four other subjects showed no clear advantage. Post-trial
(after alternating daily between strategies), of the four subjects who showed a clear
advantage for one signal processing strategy, only one subject showed that same advantage.
One subject ended up with an advantage for the other strategy. Post-trial, of the
four subjects who showed no advantage for a particular signal processing strategy,
three did show an advantage for one strategy over the other.
Conclusion: Patients are willing to alternate between signal processing strategies on a daily
basis for up to three months in an attempt to determine their optimal strategy. Although
some patients showed superior performance with initial fittings (and some did not),
the results of pre-trial comparison did not always persist after having equal listening
experience. We recommend this daily alternating listening technique when there is
interest in determining optimal performance among different signal processing strategies
when fitting hearing aids or cochlear implants.
Key Words
Bilateral - cochlear implants - hearing aids - hearing devices - hearing loss - localization
- signal processing - speech perception
