# Reliable measures of functional cortical processing of speech in adult cochlear-implant recipients

> **NIH NIH R21** · PURDUE UNIVERSITY · 2024 · $189,877

## Abstract

ABSTRACT
The development of the cochlear implant (CI) has revolutionized the treatment of severe hearing loss. Despite
its overall success, not every patient who receives a CI will benefit from this technology. The limitation lies not
within the technology itself, but primarily within the high level of diversity in the population of people who qualify
for CI surgery. Each CI recipient has a distinct hearing-loss profile and clinical background, which imparts
unique deafness-induced changes to each level of their auditory system, including the brain. Currently, it is
unclear how individual differences within the cortical auditory system, specifically in speech-evoked brain
activity, contribute to individual variability in CI speech-recognition outcomes. One reason for this gap in
knowledge is that the electromagnetic signals emitted from a CI can disrupt traditional neuroimaging methods.
A new optical neuroimaging tool, functional near-infrared spectroscopy (fNIRS), offers a CI-compatible imaging
option that is non-invasive and unaffected by electromagnetic artifact. The knowledge gained from recent
fNIRS investigations has not yet translated into clinical practice because results are often only reported at the
group level; the reliability of fNIRS measurements remains somewhat poor on the single-subject level. The
proposed research addresses this issue of reliability by controlling for the interference from systemic
physiological signals in single-subject fNIRS recordings. In Aim 1, we will determine the contribution of
naturally occurring, non-neural physiological signals to the within-subject variability in fNIRS recordings using
systemic physiology augmented fNIRS (SPA-fNIRS). In Aim 2, we will determine the relationship between CI
speech-recognition ability and speech-evoked brain activity measured via SPA-fNIRS using naturalistic
connected speech signals. This investigation will use an individualized approach to examine cortical-speech
processing in adult CI recipients. The findings from this proposal have the potential to reveal underlying
sources of individual variability in CI recipients due to differences in their cortical processing of speech. The
use of novel connected-speech passages to elicit brain activity in individual CI users will increase the
ecological validity of our approach, which is an important step toward translating research findings into clinical
practice. Our proposal aims to improve the tools used to objectively measure speech-evoked brain activity in
single subjects so that personalized auditory-rehabilitation training can be prescribed to help individuals
engage more effective speech-processing strategies.

## Key facts

- **NIH application ID:** 10877530
- **Project number:** 1R21DC021262-01A1
- **Recipient organization:** PURDUE UNIVERSITY
- **Principal Investigator:** Maureen Joyce Shader
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $189,877
- **Award type:** 1
- **Project period:** 2024-04-01 → 2027-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10877530

## Citation

> US National Institutes of Health, RePORTER application 10877530, Reliable measures of functional cortical processing of speech in adult cochlear-implant recipients (1R21DC021262-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10877530. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*