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Hearing Health Foundation (HHF) is grateful to the General Grand Chapter of the Royal Arch Masons Research Assistance (RARA) for their most generous support of Central Auditory Processing Disorder (CAPD) research as part of our Emerging Research Grants (ERG) program. 

Researchers funded by RARA have made tremendous strides toward a better understanding of CAPD, as well as developing treatments and therapies that can benefit anyone affected by the disorder, from children to the elderly. We are grateful for your investment and trust in our rigorous grant review process. We look forward to continuing our relationship and furthering CAPD research for years to come. Follow the links at right to learn about RARA grantees' projects and accomplishments by year.

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Kristi Hendrickson, Ph.D., University of Iowa

Research topic: Neural correlates of semantic structure in children who are hard of hearing

Long-Term Goal

To identify key factors that influence language outcomes in children who are hard of hearing.

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Hao Luo, M.D., Ph.D., Wayne State University

Research topic: Cochlear electrical stimulation–induced tinnitus suppression and related neural activity change in the rat inferior colliculus

Long-Term Goal

To find the underlying mechanism by which CES alters neural activity to effect changes in auditory symptoms and perceptions and to develop an optimal strategy to improve clinical trials in this area.

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Vijaya Prakash Krishnan Muthaiah, Ph.D.. University at Buffalo, the State University of New York

Research topic: Potential of inhibition of poly ADP-ribose polymerase as a therapeutic approach in blast-induced cochlear and brain injury

Long-Term Goal

To determine the mechanisms underlying both the peripheral and central aspects of blast-induced auditory neurodegeneration; and to identify and characterize potential therapeutic targets for manifestations of blast-induced traumatic brain injury, including hearing loss, cochlear synaptopathy, tinnitus, and associated deficits.

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William “Jason” Riggs, Au.D., The Ohio State University

Research topic: Electrophysiological characteristics in children with auditory neuropathy spectrum disorder

Long-Term Goal

To use objective techniques to further target and investigate physiologic properties of the auditory system, which can be used to better understand the underlying lesion/impairment; and to improve clinical cochlear implant mapping strategies for children with ANSD through the information gleaned from objective electrophysiologic testing.

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Alisha Lambeth Jones, Au.D., Ph.D., Auburn University 

Research topic: Evaluating central auditory processing (CAP), language, and cognition skills in adolescents born prematurely

Long-Term Goal

To identify patterns of deficits in auditory processing, language, and cognition skills for both children and adolescents with a premature birth history. Once patterns of deficits are identified, early intervention treatment as well as a rehabilitation program will be developed to either prevent or treat the deficit areas.

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Elliot Kozin, M.D., Massachusetts Eye and Ear, Harvard University

Research topic: Evaluation of hearing loss and quality of life in patients with mild traumatic brain injury

Long-Term Goal

To better diagnose and treat patients with auditory dysfunction following head injury, thereby minimizing hearing loss, tinnitus, and hyperacusis. The study has implications for a broad range of individuals, including those with isolated head injuries as well as those with repetitive head injuries, such as athletes and military personnel.

Published Research

Endoscopic-Assisted Surgical Repair of Superior Canal Dehiscence using a Keyhole Middle Fossa Craniotomy Approach, Operative Techniques in Otolaryngology-Head and Neck Surgery, 2019

Human Otopathology of Cochlear Implant Drill-out Procedures, Otolaryngology–Head and Neck Surgery, 2019

Patient‐reported auditory handicap measures following mild traumatic brain injury, The Laryngoscope, 2019

Peripheral Vestibular Organ Degeneration After Temporal Bone Fracture: A Human Otopathology Study, The Laryngoscope, 2019

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Khaleel Razak, Ph.D. University of California, Riverside

Research topic: Age-related hearing loss and cortical processing

Long-Term Goal

To systematically examine the optimal combination of hearing aids and behavioral and pharmacological approaches to delay or prevent the declines in complex sound processing seen in presbycusis. 

Published Research

Fabrication and Characterization of Biodegradable Metal Based Microelectrodes for In Vivo Neural Recording, MRS Advances, 2019

Reduced perineuronal net expression in Fmr1 KO mice auditory cortex and amygdala is linked to impaired fear-associated memory, Neurobiology of Learning and Memory, 2019

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Joseph Toscano, Ph.D., Villanova University

Research topic: Cortical EEG measure of speech sound encoding for hearing assessment

Long-Term Goal

To develop a clinical test for identifying auditory neuropathy and other types of hearing loss that can be used for both adults and children. 

Published Research

Electrophysiological Evidence for Top-Down Lexical Influences on Early Speech Perception, Psychological Science, 2019


JOSEph BOCHNER, PH.D., Rochester Institute of Technology

RESEARCH TOPIC: Auditory Experience, Critical Periods, and the Development of Categorical Perception in Cochlear Implant Users: A Preliminary Investigation

Long-Term Goal

To understand the impact of sensorineural (peripheral) hearing loss may extend to central auditory processing when the onset of hearing loss occurs at birth or within the first two to three years of life.


ANGELA YARNELL BONINO, PH.D., CCC-A., The University of North Carolina at Chapel Hill

Toddlers’ and preschoolers’ ability to hear speech in noise: Assessing performance with a two-interval, observer-based procedure

Long-Term Goal

To examine toddlers’ and preschoolers’ auditory functioning with stimuli that are believed to be highly related to speech and language abilities.


INYONG choi, ph.D., university of IOWA

RESEARCH TOPIC: Neural correlates of selective listening deficits in a multiple-speaker environment

Long-Term Goal

To develop clinical tests to identify specific hearing deficits that are currently undiagnosed and raise awareness of such “hidden” hearing loss.

Published Research


Christina Reuterskiöld, PH.D., new york universtiy

RESEARCH TOPIC: Rhyme Awareness in Children with Cochlear Implants: Investigating the Effect of a Degraded Auditory System on Auditory Processing, Language, and Literacy Development

Long-Term Goal

To better understand the implications of early auditory deprivation on auditory processing, language, and literacy learning in children, which will ultimately lead to improvements in targeted intervention and educational approaches for these children.


Richard A. Felix II, Ph.D., Washington State university

RESEARCH TOPIC: Neural mechanisms underlying deficits encoding temporal sound features associated with central auditory processing disorder

Long-Term Goal

To gain a thorough understanding of the neural mechanisms that govern the temporal processing of speech. This work has the potential to impact those with hearing loss by providing vital information needed for treatments designed to ameliorate listening problems associated with CAPD.

Published Research


nathan higgins, ph.D., Vanderbilt university

RESEARCH TOPIC: Biomarkers of spatial processing in auditory cortex measured with functional near-infrared spectroscopy

Long-Term Goal

To establish consistent biomarkers for central auditory processing, and determine the utility of fNIRS for a variety of patientpopulations by quantifying the influence of task-related attention on cortical activity.

Published Research


Elizabeth McCullagh, Ph.D., university of colorado

RESEARCH TOPIC: The role of the MNTB in sound localization impairments in autism spectrum disorder and CAPD

Long-Term Goal

To verify a theory that autism may be caused by an imbalance of excitatory and inhibitory synapses, particularly in sensory systems, which would lead to a decreased ability to separate competing sound sources.

Published Research


Nirmal Kumar Srinivasan, Ph.D., towson university

RESEARCH TOPIC: Understanding and decoding CAPD in adults

Long-Term Goal

To better understand the difficulties encountered by listeners with CAPD in complex listening environment.

Published Research


Hari Bharadwaj, Ph.D., massachusetts general hospital

RESEARCH TOPIC: A systems approach to characterization of subcortical and cortical contributions to temporal processing deficits in CAPD

Long-Term Goal

To understand the physiological mechanisms that allow us to listen and communicate in noisy settings, thereby illuminating why different groups of individuals have difficulty in such settings, and to leverage this understanding to develop noninvasive objective tools that can be used in the diagnosis and stratification (“subtyping”) of a diverse yet overlapping set of communication disorders.

Published Research

NIH Funding

  • Years: 2017-2019

  • Total: $1,130,840.00 

  • Topic: Individualized assays of supra-threshold hearing deficits


Andrew Dimitrijevic, Ph.D., Cincinnati Children's Hospital Medical Center

RESEARCH TOPIC: SensorY and Cognitive Processing in Children with Auditory Processing Disorders: Behavior and Electrophysiology

Long-Term Goal

To address whether there are subtypes of CAPD arising from deficits of bottom-up or top-down processing. Bottom-up processing refers to how the sound signal is encoded up to the level of the brain (i.e., ear to auditory nerve through the brainstem and up to the brain). Top-down processing is what the brain does with that information and includes cognition and attention. Understanding the mechanism of the CAPD will help direct clinicians as to what intervention may be most appropriate.

Published Research


Beula Magimairaj, Ph.D., CCC-SLP., University of Central Arkansas

RESEARCH TOPIC: Moving the science forward through interdisciplinary collaborative research integrating hearing, language, and cognitive science

Long-Term Goal

To develop a sensitive and valid test that can serve as a front-end differential screening tool for children suspected to have CAPD. Such an assessment tool will be able to reliably characterize auditory processing and attention, language, and memory deficits that are known to coexist in some children diagnosed with CAPD.

Published Research


KENNETH Vaden, medical university of South Carolina

RESEARCH TOPIC: Adaptive control of auditory representations in listeners with central auditory processing disorder

Long-Term Goal

To develop methods to assess the quality of speech representations based on brain activity and characterize top-down control systems that interact with the auditory cortex. The results of this study will improve the understanding of a specific top-down control mechanism and examine when and how adaptive control enhances speech recognition for people with CAPD.

Published Research


Samira Anderson, Au.D., Ph.D., university of maryland

RESEARCH TOPIC: Neural adaptation in new hearing aid users

Long-Term Goal

To improve the hearing aid fitting process through assessment of the brain’s sound processing and to determine how this processing changes with hearing aid use over the course of six months.

Published Research

NIH Funding

  • Years: 2016-2018

  • Total: $435,702.00 

  • Topic: Age-related changes in neural encoding and perception of temporal speech cues


Srikanta Mishra, Ph.D, new mexico state university

RESEARCH TOPIC: Medial Efferent Mechanisms in Auditory Processing Disorders

Long-Term Goal

To understand the role efferent mechanisms in auditory processing, learning and disability. The translational goal is to develop mechanism-based and physiological tests for assessing auditory processing.

Published Research

NIH Funding

  • 2016-2018

  • Total: $461,342.00 

  • Topic: Medial olivocochlear reflex in children


Daniel Winkowski, Ph.D., University of maryland

RESEARCH TOPIC: Noise trauma induced reorganization of the auditory cortex

Long-Term Goal

To understand tinnitus at the level of neural circuits (auditory processing). Our approach offers a rather unique opportunity to sample activity within large-scale representations and local populations of neurons and, in turn, will reveal precisely how A1 micro-circuits are affected by traumatic insult to peripheral sensory organs. Thus, I intend on using this approach to build a more comprehensive understanding of how cortical micro-circuits change as a result of noise trauma.

Published Research


BRENTON cooper, PH.D., Texas Christian University

RESEARCH TOPIC: Lateralization of acoustic perception in Bengalese finches

Long-Term Goal

To develop this animal model for testing and refining treatments for hearing loss and lateralized frequency processing deficits in humans, including CAPD.

Published Research

NIH Funding

  • Years: 2018-2019

  • Total: $1,200,609.00 

  • Topic: Neural sequences for planning and production of learned vocalizations


ALAN KAN, PH.D., University of Wisconsin, Madison

RESEARCH TOPIC: Exploiting the “better ear” in bilateral cochlear implants for improved speech understanding in noisy situations and Auditory Processing.

Dr. Kan was also funded for his research in 2014.

Long-Term Goal

To close the gap in speech understanding performance between cochlear implant users and normal hearing listeners. The primary outcome of this study will help determine whether the “better ear” strategy will provide a significant benefit for cochlear implant users, and whether this strategy for listening is desirable.

Published Research

NIH Funding

  • Years: 2016-2018

  • Total: $459,000.00

  • Topic: Restoring Binaural Hearing Abilities to Bilateral Cochlear Implant Users



RESEARCH TOPIC: Relating behavior to brain in an audio-visual scene

Long-Term Goal

To investigate the specific behavioral effects of audio-visual binding and its processing in the brain.

Published Research

NIH Funding

  • Years: 2015-2018

  • Total: $1,012,223.00

  • Topic: Visual and Auditory Perceptual Factors Affecting Spatial Release from Masking


MERRI J. Rosen, Northeast Ohio Medical University

RESEARCH TOPIC: Effects of developmental conductive hearing loss on communication processing

Long-Term Goal

Effects of developmental conductive hearing loss on communication processing: perceptual deficits and neural correlates in an animal model.

Published Research

NIH Funding

  • Years: 2014-2018

  • Total Funds Awarded: $1,844,408.00

  • Topic: Auditory Processing Deficits in Early-Onset Conductive Hearing Loss


Yoojin Chung, Ph.D., Mass. Eye and Ear

RESEARCH TOPIC: Restoring binaural hearing with cochlear implants in early-onset deafness


Long-Term Goal

To improve treatments for children with early-onset deafness by studying how neural mechanisms for binaural processing are altered by auditory deprivation during development and whether these effects can be reversed by CI stimulation.

Published Research


Elizabeth Dinces, M.D., M.S., Albert Einstein College of Medicine

RESEARCH TOPIC: Effects of aging on selective attention in complex, multisource sound environments

Long-Term Goal

To explain mechanisms of auditory scene analysis that break down in aging.

Published Research


Kirill Vadimovich Nourski, M.D., Ph.D., University of Iowa

Research Topic: Temporal Processing in the Human Auditory Cortex

Long-Term Goal

To better understand how the different areas that comprise the auditory cortex in humans are organized and what specific roles they play in processing information about sounds, particularly, as it relates to perception of speech. Ultimately, this knowledge will contribute to finding new and/or improved solutions for people with hearing loss and auditory processing disorders.

Published Research

NIH Funding

  • Years: 2018-2019

  • Total: $1,013,625.00 

  • Topic: Mechanisms of anesthetic-induced unconsciousness

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Edward L. Bartlett, Ph.D., PURDUE UNIVERSITY

RESEARCH TOPIC: Cellular bases of temporal auditory processing

Long-Term Goal

To predict and redevelop the cellular dynamics that underlie in vivo responses of auditory thalamic and auditory cortical neurons in normal and pathological conditions, including age-related decline, dyslexia, and aberrant auditory experience during development.

Published Research

NIH Funding

  • Years: 2012-2016

  • Total Funds Awarded: $1,706,568

  • Topic: Measurement and Modeling of CAPD in Aged Animals

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Zhengqing Hu, M.D., Ph.D., Wayne State University school of Medicine

RESEARCH TOPIC: Innervation of in vitro-produced hair cell by neural progenitor-derived glutamatergic neurons

Long-Term Goal

To develop effective strategies to regenerate auditory pathways using stem cell-based approaches to restore hearing. If successful, the research will then explore whether stem cell-derived cells can be used to regenerate auditory cells damaged in CAPD.

Published Research

NIH Funding

  • Years: 2014-2019

  • Total Funds Awarded: $1,615,000

  • Topic: Regeneration of Auditory Synaptic Contacts Using Stem Cell Based Approaches

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Judith S. Kempfle, M.D., MASS. EYE AND EAR

RESEARCH TOPIC: Influence of bone morphogenetic protein 4 and retinoic acid on differentiation of inner-ear stem cells


Long-Term Goal

The better understanding of pathways and drug screening in order to develop a drug that can be easily applied to the ear and that can stimulate dormant inner-ear stem cells in vivo for regeneration strategies after hearing loss.

Published Research

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RESEARCH TOPIC: A stem cell-seeded nanofibrous scaffold for auditory nerve regeneration

Long-Term Goal

To regenerate auditory nerves and understand the conditions that promote neural connections with the auditory brainstem, in order to ultimately restore hearing for patients with neural hearing loss and find for therapies for individuals with CAPD.

Published Research

NIH Funding

  • Years: 2015, 2016

  • Total Funds Awarded: $379,401

  • Topics: Optical Control of Network Formation in Stem Cell-Derived Neurons, Plasticity in the Electrical Properties of Neurons Surrounding Neuroprostheses