Effect of Directional Microphone Technology in Hearing Aids on Neural Correlates of Listening and Memory Effort: An Electroencephalographic Study.
Axel H Winneke, Michael Schulte, Matthias Vormann and 1 others
PMID 32833586WHAT IT FOUND
Experienced hearing aid users with severe hearing loss reported less listening and memory effort, and showed better memory performance, when using narrow directional microphones compared to wide ones.
EEG data confirmed reduced brain activity associated with effort for the narrow setting.
Key findings
01Subjective listening effort ratings were significantly higher with wide directional microphones compared to narrow ones, particularly in noisy conditions.
02Narrow directional microphones resulted in significantly lower alpha band EEG activity during listening tasks, suggesting reduced neural effort in suppressing background noise.
03Memory performance was better and subjective memory effort lower with narrow directional microphones, even when speech intelligibility was high.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study included only 20 participants, with slightly fewer analyzed for EEG data due to technical issues. Speech intelligibility was not measured in the low and medium noise conditions of Experiment 1, so differences in effort ratings could partially reflect differences in how much was understood, although the authors argue this is unlikely at high SNRs. The study compared two directional microphone settings but did not include a 'no noise reduction' baseline, so the absolute benefit of any directional technology versus none is not shown. The number of trials in Experiment 2 was low, which can affect the signal-to-noise ratio in EEG data. Participants were screened for normal memory functioning, so results may not generalize to those with cognitive decline.
Declared interests
The paper does not explicitly state funding sources or conflicts of interest in the provided text.
The easy way to misread this
Do not assume that narrow directional microphones will improve speech recognition scores in quiet or easy listening situations. The study found that at the highest signal-to-noise ratio (easiest condition), there was no significant difference in EEG effort between narrow and wide microphones during the listening task. The benefits were most clear in noisy conditions or during complex memory tasks.