Joshua M. Alexander, PhD, CCC-A

Research Interests / Training Areas:

  • Amplification
  • Speech Perception
  • Auditory Perception


Joshua M. Alexander received his Ph.D. in Audiology (psychoacoustics) and post-doctoral training in speech perception at the University of Wisconsin- Madison. Before coming to Purdue, he completed both clinical and post-doctoral fellowships at Boys Town National Research Hospital in Omaha, Nebraska.

Research interests focus on auditory processes contributing to speech perception deficits in hearing-impaired listeners and signal processing techniques to overcome them. Ongoing projects include work on frequency-lowering techniques, wide dynamic range compression, and speech enhancement techniques. Dr. Alexander has been awarded 3 U.S. patents (US 9,173,041 B2; US 9,706,314 B2; US 10,083,702 B2) related to methods of frequency lowering and speech enhancement. Discovery is aided by an innovative approach by which signal processing techniques like these and realistic hearing aid amplification are simulated in the laboratory on a PC. This allows the researchers in the lab to know precisely the effect that their manipulations have on the acoustic signal as they try to relate listener performance back to psychophysical estimates of cochlear filtering, auditory nerve models, and cognitive processing.

The framework guiding the discovery process involves the interplay of three key components: basic research (speech perception and psychoacoustic deficits); applied research (digital signal processing algorithms intended for hearing aids and automatic speech recognition); and modeling. Ongoing efforts encompass two main lines of research: understanding existing technology and developing new technology. Recently, effort has been directed towards developing auditory nerve models that quantify information in a speech signal to help explain the effects that different signal processing strategies have on speech perception as a function of hearing loss so that better solutions can be devised.

Recent Publications:

  • Rallapalli, V., and Alexander, J.M. (2019).  Effects of noise and reverberation on speech recognition with variants of a multichannel adaptive dynamic range compression scheme.  International Journal of Audiology.  In press.

  • Alexander, J.M. (2019).  The s-sh confusion test and the effects of frequency lowering.  Journal of Speech Language and Hearing Research, 62, 1486-1505.

  • Plotkowski, A., and Alexander, J.M. (2016).  A sequential sentence test paradigm using revised PRESTO sentence lists.  Journal of the American Academy of Audiology, 27, 647-660.

  • Alexander, J.M. (2016).  Nonlinear frequency compression: Influence of start frequency and input bandwidth on consonant and vowel recognition.  Journal of the Acoustical Society of America, 139, 938-957.

  • Alexander, J.M., and Masterson, K.M. (2015).  Effects of WDRC release time and number of channels on output SNR and speech recognition.  Ear and Hearing, 36, e35-e49.
Joshua Alexander
Associate Professor

Lyles-Porter Hall, Room 3076
Phone: 765-494-4091

Purdue Experimental Amplification Research (EAR) Lab

Google Scholar page

Speech, Language, & Hearing Sciences, Lyles-Porter Hall, 715 Clinic Drive, West Lafayette, IN 47907-2122, PH: (765) 494-3789

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