Howling and Entrainment in Hearing Aids: A Review


  • Muhammad Tahir Akhtar COMSATS Institute of Information Technology
  • Akinori Nishihara Tokyo Institute of Technology



Hearing aids, adaptive filtering, NLMS algorithm, acoustic feedback, howling, entrainment.


This review focuses on howling and entrainment artifacts in digital hearing aids. The howling may occur (especially at high gains), essentially due to the close proximity of the input microphone and the output loudspeaker. The entrainment, on the other hand, occurs when the input to the hearing aids is periodic, for example, music signals or alarm signals with strong tonal characteristics. We give details on methods for howling avoidance, which are mainly based on adaptive filtering-based acoustic feedback cancellation. We also give an overview of many recent works on entrainment in hearing aids. Finally, we remark that efficient acoustic feedback cancellation scheme which can avoid howling, can also well manage the entrainment artifact.


Download data is not yet available.

Author Biographies

Muhammad Tahir Akhtar

Department of Electrical Engineering, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad 44000, Pakistan

Akinori Nishihara

Human Assets Promotion Program for Innovative Education and Research (HAPPIER), Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8552, Japan


Published In
Vol 20 No 5, Nov 25, 2016
How to Cite
M. T. Akhtar and A. Nishihara, “Howling and Entrainment in Hearing Aids: A Review”, Eng. J., vol. 20, no. 5, pp. 5-13, Nov. 2016.