Shuman He, MD, PhD

Cochlear implant (CI) users who are 65 years or older typically show poorer speech perception performance than younger adult CI users, especially in competing background noise. The underlying mechanisms remain unclear. Whereas declined cognitive function has been proposed as the major factor, deteriorations in the auditory system have also been suggested to be the primary reason. As a result, there is no robust indicator for optimizing programming settings or habilitation strategies for older implanted patients. The long-term goal of this research is to better understand the neurophysiologic basis of speech perception deficits in older (≥ 65 years) CI users. As the first step to achieve this long-term goal, this study is designed to better understand underlying neurophysiological mechanisms of speech perception deficits in older CI users. Older listeners are known to have temporal processing deficits, and temporal cues are particularly important for discriminating speech in CI users. Therefore, the proposed study will focus on comparing peripheral and central auditory neural encoding of, and perceptual sensitivity to, temporal envelope cues between younger and older adult CI users. 

Cochlear nerve deficiency (CND) refers to a small or absent cochlear nerve (CN) as revealed by high-resolution magnetic resonance imaging. Cochlear implantation has been used as a treatment option for children with CND for nearly two decades. Due to the lack of understanding of how electrical stimulation is encoded and processed in their auditory system, there is still no evidenced-based clinical practice for managing this unique patient population. To further complicate matters, more than half of children with CND cannot provide reliable behavioral responses despite their age due to severe comorbidities. As a result, clinicians often use a combined “one-size-fits-all” and “try-and-see” approach to program cochlear implant (CI) speech processors for children with CND. This practice typically results in stimulating all intra-cochlear CI electrodes with similar programming parameters. However, recent work from our lab showed that the likelihood of measuring CN neural responses in children with CND reduced as the stimulating CI electrode site moved from the base to the apex of the cochlea. This unique response-deterioration pattern is not observed in children with normal-sized CNs. In addition, our compiling preliminary data show that information transmitted by CI electrodes with no measurable CN response is only adequate for auditory detection but not sufficient for auditory discrimination, which explains why the majority of children with CND do not make satisfactory progress in speech and language development despite good auditory detection thresholds with their CIs. These new findings suggest that the current clinical practice is unlikely to provide appropriate CI programming settings for this unique patient population. Therefore, there is an urgent need to develop objective clinical tools for optimizing CI settings for individual children with CND. Our long-term goals are 1) to understand neural encoding and processing of electrical stimulation in children with CND, and 2) to develop an effective, evidence-based clinical practice for managing this unique patient population.  As the first step toward these long-term goals, this study aims to better understand neural encoding and processing of electrical stimulation in both the CN and the central auditory system in implanted children with CND. 

Usher syndrome (USH) is an autosomal recessive disorder characterized by hearing loss, visual impairment, and in some cases, vestibular dysfunction. It is the leading cause of hereditary deaf-blindness in humans. USH causes extensive degeneration in the cochlear nerve (CN), especially in CN fibers innervating the base of the cochlea. Whereas there is no treatment for arresting this degenerative process or for restoring visual loss, the restoration of auditory input is possible with cochlear implantation. Due to the progressive deterioration in vision, using visual cues for communication will eventually become impossible. Therefore, the importance of optimizing auditory inputs through cochlear implants (CIs) for patients with USH is paramount. However, patients with USH have much higher rates of neurological, mental, or behavioral disorders than the general CI patient population, which limits their ability to provide reliable behavioral responses or sufficient verbal descriptions of their auditory perception, especially for pediatric patients. In addition, optimal programming parameters for CI users with CN damage differ from those used in typical CI users due to declined CN responsiveness to electrical stimulation. As a result, the clinical programming process in implanted patients with USH can be extremely challenging. To date, auditory neural encoding of electrical stimulation in patients with USH has not been systematically evaluated. Consequently, the field lacks evidence-based practice guidelines for managing implanted patients with USH. For patients who cannot provide reliable feedback, clinicians rely on a “trial-and-error” approach for adjusting CI programming settings, which ultimately may not result in appropriate programming maps for individual patients. Therefore, there is an urgent need to develop objective clinical tools for optimizing CI settings for these patients. As the first step toward developing evidence-based practice for managing patients with USH, this study evaluates local neural health, as well as the neural encoding of temporal and spectral cues at the CN in implanted patients with USH.

In addition to these three main projects described above, we are collaborating with Dr. Raymond L. Goldsworthy at University of Southern California on studies investigating 1) neural encoding and auditory perception of temporal fine structure, and 2) music appreciation in cochlear implant users. We are also collaborating with Dr. Aaron C. Moberly at The Ohio State University College of Medicine on a research study that aims to identify predictive factors for speech perception in adult cochlear implant users.

Title: Neural encoding and auditory perception in cochlear implant users
Dates: 7/1/2017 – 6/30-2022
Name of agency: NIDCD and NIGMS
Role: Principal Investigator 
Award number: 1 R01 DC016038 

Title: Neural encoding and auditory processing in pediatric cochlear implant users
Dates: 4/1/2019 – 3/30-2024
Name of agency: NIDCD 
Role: Principal Investigator 
Award number: 1 R01 DC017846

Title: Music appreciation after cochlear implantation
Dates: 9/12/2019 – 8/30-2024
Name of agency: NIDCD and NINDS 
Role: Consortium Principal Investigator 
Award number: 1 R01 DC018701

Title: Encoding temporal fine structure for cochlear implant
Dates: 3/1/2020 – 2/28-2025
Name of agency: NIDCD 
Role: Consortium Principal Investigator 
Award number: 1 R01 DC018044A1

Title: Auditory function in implanted patients with Usher Syndrome
Dates: 4/1/2021 – 3/30-2023
Name of agency: NIDCD 
Role: Principal Investigator 
Award number: 1 R21 DC019458

Title: Predicting speech recognition in adults receiving cochlear implants
Dates: 7/1/2021 – 6/30-2026
Name of agency: NIDCD 
Role: Co-investigator 
Award number: 1 R01 DC019088A1

Yuan, Y., Skidmore, J., and He*, S. (2022). Interpreting the interphase gap effect on the electrically evoked compound action potential.  JASA Express Letters, (In press). 

He*, S., Skidmore, J., and Carter, B. (2022). Characteristics of the adaptation recovery of the auditory nerve and its association with advanced age in postlingually deafened adult cochlear implant users. Ear and Hearing, (In press). 

He*, S., Skidmore, J., Conroy, S., Riggs, W.J., Carter, B., and Xie, R. (2022). Neural adaptation of the electrically stimulated auditory nerve is not affected by advanced age in postlingually deafened, middle-aged, and elderly adult cochlear implant users.  Ear and Hearing, January 3 (Epub ahead of print). 

Skidmore, J., Carter, B.L., Riggs, W.J., and He*, S. (2021). The effect of advanced age on the electrode-neuron interface in cochlear implant users. Ear and Hearing, December 21 (Epub ahead of print). 

Skidmore, J., Ramekers, D., Colesa, D.J., Schvartz-Leyzac, K.C., Pfingst, B.E., and He*, S. (2021). A broadly applicable method for characterizing the slope of the electrically evoked compound action potential amplitude growth function recorded from cochlear implants. Ear and Hearing, 43, 150-164.  

Riggs, W.J., Vaughan, C., Skidmore, J., Conoy, S., Pellittieri, A., Carter, B, and He*, S. (2021). The sensitivity of the electrically-stimulated auditory nerve to amplitude modulation cues declines with advanced age. Ear and Hearing, 42, 1358-1372. 

Zhan, K.Y., Adunka, O.F., Eshraghi, A., Riggs, W.J., Prentiss, S.M., Yan, D., Liu, X.Z., and He*, S. (2021). Electrophysiology and genetic testing in the precision medicine of congenital deafness. Journal of Otology, 16, 40-46. 

Skidmore, J., Xu, L., Riggs, W.J., Pellittieri, A., Vaughan, C., Ning, X., Wang, R., Luo, J., and He*, S. (2020). Prediction of the functional status of the cochlear nerve in cochlear implant users using supervised machine learning. Ear and Hearing, 42, 180-192. 

Skidmore, J., and He*, S. (2020). Cochlear nerve function and the effect of increasing interphase gap on neural response in cochlear implant users. Ear and Hearing,42, 244-247. 

McFayden, T.C., Baskin, P., Stephens, J.W., He*, S. (2020). Auditory perception and neural representation of voice onset time in children with auditory neuropathy spectrum disorder. Frontiers in Human Neuroscience, 14, 184. 

 

Vice Chair of Research, 2021 - Current 
Department of Otolaryngology - Head and Neck Surgery
The Ohio State University College of Medicine, Columbus, Ohio

Professor, 2018 - Current
Department of Otolaryngology - Head and Neck Surgery
The Ohio State University College of Medicine, Columbus, Ohio

Accelerator Awards, The Ohio State University, 2021

Ruberg Award, The Ohio State University, 2020

Dean’s List, The Ohio State University Wexner Medical Center, 2018

Ear and Hearing 2018 Editor’s Award Nominee for Outstanding Contribution to the Literature on Hearing and Balance  

Auditory Neuropathy Spectrum Disorder 2014 Award, 8th International Symposium on Objective Measures in Auditory Implants

New Investigator Award, 8th International Symposium on Objective Measures in Auditory Implants 2014

Junior Faculty Career Development Award, UNC-Chapel Hill, 2014

Eunice Beam WISE Travel Award, University of Iowa, 2008

Graduate Student Senate Travel Funds Award, University of Iowa, 2008

Research and Teaching Assistantship, University of Iowa, 2003-2008  

NIH funded Student Travel Award, Conference on Implanted Auditory Prostheses, 2007 

Scholarship, Communication Sciences and Disorders Summer Institute, 2007

NIH Funded Student Travel Award, American Auditory Society, 2005

Teaching Activities 

• Instructor, University of North Carolina at Chapel Hill

               Auditory Evoked Potential II (Fall, 2009, 2010, 2011)

   

• Teaching Assistant, University of Iowa

   Introduction of Hearing Science (Fall, 2006, 2007)

               Basic Acoustics for Speech & Hearing (Spring, 2006, 2007)

   

• Teaching Assistant, Northwestern University

  Aural Rehabilitation (Spring, 2002).        

• Laboratory Instructor, Shandong Medical University

      Clinical Diagnosis (Spring, 1999, 2000, 2001)

Mentoring

Ph.D Student Advised

Xiuhua Chao (exchange Ph.D candidate from Shandong University)

Medical Students Advised (Including Medical Residents)

Anna X.Z. Hang

Paola Lopomo

AuD Student Advised

Heather Strader

Alexandria Gary

Danielle M. Verilli

Katherine Gill

Undergraduate Student Advised

Nancy He

Travis Warren

Jared Beckham

Stephen Mulherin