Skip navigation

Seminars in Hearing Research (10/1/20) - Josh Alexander, PhD

Seminars in Hearing Research (10/1/20) - Josh Alexander, PhD

Author: M. Heinz
Event Date: October 1, 2020
Hosted By: Hari Bharadwaj
Time: 1030-1120
Location: Zoom
Contact Name: Bharadwaj, Hari M
Contact Email:
Open To: All
Priority: No
School or Program: Biomedical Engineering
College Calendar: Show
Assoc. Prof. Josh Alexander (Department of Speech, Language, and Hearing Sciences) will present "Validity of the peak height insertion gain (PHIG) for quantifying acoustic feedback in hearing aids" at our first Seminar in Hearing Research at Purdue (SHRP) this semester, on October 1st at 1030-1120 on Zoom.

Seminars in Hearing Research at Purdue (SHRP)

Title:  Validity of the peak height insertion gain (PHIG) for quantifying acoustic feedback in hearing aids


Speaker(s): Joshua M. Alexander, Ph.D., Associate Professor, SLHS


Date: Oct 1, 2020
Time: 10:30 – 11:20 am
Location: Zoom**


Joshua M. Alexander1, Stephanie Trippel1, Randall Wagner2, and Steve Armstrong3

Purdue University, West Lafayette, Indiana

National Institute of Standards and Technology, Gaithersburg, Maryland

3  SoundsGood Labs, Ontario, Canada



Hearing aids are commonly fit with the ear canal partially or fully open – a condition that increases the risk of acoustic feedback.  By limiting usable gain, feedback limits the audiometric fitting range of a device.  To guide clinical decision-making and device selection, we devised the Peak Height Insertion Gain (PHIG) method for detecting feedback spikes and spectral ripple in the insertion gain spectra derived from audio recordings.  Using a manikin, 145 audio recordings of a speech sample were obtained from seven hearing aids.  Each hearing aid was programmed for a moderate high-frequency hearing loss with systematic variations in the frequency response, gain, and feedback suppression; this created audio recordings that varied the presence and strength of feedback.  Using subjective ratings from 13 expert judges, the presence of feedback was determined and then classified according to its temporal and tonal qualities.  These classifications were used to optimize parameters of two versions of the PHIG based on a global and a local analysis of time-frequency bins.  By combining the results obtained from these two PHIG methods and setting specificity to 0.95, sensitivity was ≥ 0.94 for all categories of feedback, except “infrequent.”  Without compromising performance, a clinically expedient version of PHIG can be obtained using only a single measurement.


**Please e-mail the host to join the SHRP seminar mailing list. Seminar announcements and Zoom links are sent to the mailing list on a weekly basis.


The working schedule for this semester is at:

The titles and abstracts of the talks are here: