Title: Scalp-recorded neural activity evoked by frequency-specific speech stimuli can be detected within 15 dB of hearing threshold
Legend: EEG is currently the only clinically feasible method to evaluate hearing in infants and children who are unable to participate in behavioral hearing tests. We modified naturally spoken vowels and fricatives to elicit envelope following responses (EFR) at low, mid and high frequencies–the prime spectral regions essential for speech understanding, and speech and language development. The minimum sensation level (SL), which refers the dB above threshold, necessary to elicit a detectable scalp-EFR varies by the speech stimulus. F1= First formant of vowels; F2+= second and higher formants of vowels; arrows=one-sided 95% confidence intervals; horizontal lines= two-sided 95% confidence intervals; p-value refers to the probability of an EFR being detected using Hotelling’s T2.
Citation: Easwar, V., Birstler, J., Harrison, A., Scollie, S., & Purcell, D. (in review). The accuracy of envelope following responses in predicting speech audibility
About the Lab: Viji’s research focuses on the development of hearing in children with or without hearing loss. In particular, she is interested in investigating the effects of age, auditory deprivation, and hearing prostheses like hearing aids or cochlear implants on how sounds, particularly speech stimuli, are encoded by the auditory system using electroencephalography (EEG) techniques. In addition, she is interested in evaluating how these factors affect the ability of the auditory system to decipher where sounds are located in space. The goal of her research is to develop evidence that can help inform intervention strategies in children with hearing loss and extend the use of EEG techniques to clinical practice to help clinicians (audiologists) evaluate intervention outcomes in children.