Frequency following response (FFR): examining the variability of this complex response

Author/Creator

Author/Creator ORCID

Date

2017-09-13

Department

Towson University. Department of Audiology, Speech-Language Pathology and Deaf Studies

Program

Citation of Original Publication

Rights

Subjects

Abstract

Objectives: The goal of the current study was to investigate the subject-related variations seen in the Frequency Following Response (FFR) in normal hearing listeners. We examined the subject factors of musical experience and gender to determine what, if any, effect these had on FFR amplitudes recorded in response to low frequency pure tone stimuli. Methods: Thirty normal hearing adults were recruited as participants in the study. FFRs were recorded for each participant using three stimuli: 250 Hz, 500 Hz, and 1000 Hz pure tones. Participants were grouped based on length of musical training and by gender. Fast Fourier Transform (FFT) analysis was performed on FFR waveforms reflecting brainstem neural representation of temporal fine structure (FFRTFS). Analyses of Variance (ANOVAs) were performed to investigate the effect of stimulus frequency on brainstem neural representation of pitch, and to investigate the effect of musical training and gender on the brainstem neural representation of a 250 Hz pure tone stimulus. Results: Significant differences in FFR amplitudes were seen between each stimulus frequency (250, 500, and 1000 Hz), such that larger FFR amplitudes were seen for lower frequency stimuli. For FFRs recorded in response to the 250 Hz stimulus, no significant effects of gender or musicianship were seen. Conclusions: Examination of subject-related variability within normal hearing listeners is an important step toward introducing the FFR into the audiology clinic. Further research on the variability in the FFR across the lifespan, in individuals with normal hearing and hearing loss, in varying stages of sleep and attention, is necessary before the FFR can become a clinical tool.