Synchronized Automatic Gain Control in Bilateral Cochlear Implant Recipients Yields Significant Benefit in Static and Dynamic Listening Conditions.
Robert T Dwyer, Chen Chen, Phillipp Hehrmann and 2 others
PMID 34027718WHAT IT FOUND
Synchronizing the automatic gain control in bilateral cochlear implants significantly improved the ability to locate stationary and moving sounds.
Participants found the tasks less difficult. This technique preserves level differences between ears, which are normally distorted by independent processing.
Key findings
01Synchronized AGC significantly improved the minimum audible angle (static localization) compared to independent AGC.
02Synchronized AGC significantly improved the minimum audible movement angle (dynamic localization) compared to independent AGC.
03Participants reported significantly lower difficulty for both static and dynamic localization tasks when using synchronized AGC.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study was acute, meaning it tested the effect of the programming change immediately. It did not evaluate the impact of long-term use of synchronized AGC, so it is unknown if performance would change with device experience. The research program used an infinite compression ratio due to technical limitations, whereas the clinical program used a 12:1 ratio. Although the authors argue this should not affect the results, it is a difference between the tested conditions. The study used white noise stimuli. The authors note that the distortion of interaural level differences by independent AGC depends on the frequency content of the stimulus, so results may differ for other sounds like speech. The sample size was small (12 participants).
Declared interests
One author is on the advisory board for Advanced Bionics, Cochlear, and Frequency Therapeutics. Two authors are employed by Advanced Bionics. The study used Advanced Bionics devices and research processors.
The easy way to misread this
Do not assume this benefit will be identical for all patients or in all listening situations. The study used white noise in a quiet chamber, and the long-term effects of using synchronized AGC in daily life were not tested. Also, note that the research program differed slightly in compression ratio from the clinical program due to technical constraints.