Assistive Listening Knowledge Base
  • Peer-reviewed study (single-blind repeated measures)

Detection, Speech Recognition, Loudness, and Preference Outcomes With a Direct Drive Hearing Aid: Effects of Bandwidth

From https://assistivelisteningknowledgebase.org/evidence/folkeard-2021-bandwidth/ · record checked 13 October 2026

  • Folkeard P, Van Eeckhoutte M, Levy S, Dundas D, Abbasalipour P, Glista D, Agrawal S, Scollie S
  • Trends in Hearing 25:2331216521999139

Manufacturer (Earlens funded the direct study costs at the National Centre for Audiology; two authors were Earlens employees and one served on its audiology advisory board)

Summary

Tested full versus restricted bandwidth through fitted Earlens direct-drive hearing devices in 15 adults.

Key findings

  • Fifteen adult hearing aid users with symmetric sensorineural loss wore the devices for 4-15 weeks before outcome testing; full bandwidth provided measurable audibility to 10 kHz, compared with a restricted condition reducing gain above 5 kHz.
  • Full bandwidth improved sentence reception in competing speech by 1.1 dB on average across spatial configurations and improved high-frequency consonant recognition and detection.
  • Results, Loudness Ratings and Preference: full bandwidth produced a small but perceptible loudness increase. Eight of 15 participants preferred full bandwidth, six had no preference and one preferred restricted bandwidth.
  • Real-world acclimatisation used only full bandwidth, which the authors note could influence preferences; preference tests used speech in quiet.

Limits

Manufacturer-funded, small study of one direct-drive hearing device. Shared evidence on the audible bandwidth of a listening path; no venue transmitter or codec was tested. Full PMC text read through the Wayback Machine; supplementary files were not read.

Read the original

pmc.ncbi.nlm.nih.gov/articles/PMC8060758

Link checked . We link to the original and do not host copies.

Cited in

Cite this source

Folkeard P, Van Eeckhoutte M, Levy S, Dundas D, Abbasalipour P, Glista D, Agrawal S, Scollie S. Detection, Speech Recognition, Loudness, and Preference Outcomes With a Direct Drive Hearing Aid: Effects of Bandwidth. Trends in Hearing 25:2331216521999139. 19 April 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC8060758/ (accessed 13 October 2026).

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