Nathan Higgins, Ph.D.
Meet the Researcher
Higgins received his Ph.D. at the University of Connecticut, where he was mentored by Heather Read, Ph.D., and studied neural responses to interaural level difference cues in rat auditory cortex.
He is now a postdoctoral research fellow with Christopher Stecker, Ph.D., at Vanderbilt University.
The Research
Vanderbilt University
Biomarkers of spatial processing in auditory cortex measured with functional near-infrared spectroscopy
Central auditory processing disorders (CAPD) comprise a number of functional deficits, such as impairments in the ability to process complex information used for localizing, fusing, and discriminating acoustic objects or streams. Binaural hearing (integrating information from the two ears) represents a fundamental aspect of central auditory processing and can be objectively measured in the brain using biomarkers such as the blood oxygenation level-dependent (BOLD) signal in the auditory cortex.
Functional near-infrared spectroscopy (fNIRS) is an emerging technique for measuring the BOLD signal, and is well suited for study of CAPD clinically due to its low noise, portability, and cost-effectiveness. As a clinical tool for objective measures of central auditory processing, fNIRS has a bright future. This project will measure fNIRS sensitivity to binaural tuning of BOLD responses, testing the hypothesis of broad contralateral tuning as seen with fMRI. Attention will be manipulated by tasks requiring feature detection in different modalities (location, pitch, visual). Also to be measured is the effect of task engagement on the BOLD signal, compared with passive listening, in order to yield an objective biomarker of cortical processing for task-related attention. This is an important tool when examining clinical populations (e.g. young children) who are unable to provide reliable feedback.
Long-term goal: To establish consistent biomarkers for central auditory processing, and determine the utility of fNIRS for a variety of patient populations by quantifying the influence of task-related attention on cortical activity. This will aid the development of neuroimaging-based assessments of central auditory function that can then be used by clinicians to help diagnose and focus treatment for individuals with CAPD. In addition, since fNIRS is still gaining acceptance within research and clinical fields, and is in many ways largely untapped, this project may help establish fNIRS as a research and clinical tool.
