Exploring the effect of stimulus complexity, frequency and intonation on the FFR

Abstract

Abstract: Frequency following responses (FFRs) can be evoked by a wide range of stimuli. As a result, studies often use different stimuli, complicating the comparison of their results. Besides, it is not very clear which stimuli provide the largest response SNRs, which is important information in the context of clinical applications. To bring some clarity to this matter, we explore the parameter space of three important stimulus parameters and studied the effect on the SNR of the FFR in normal hearing individuals. The first parameter incorporated in the study is the complexity of the stimulus, i.e. from simple modulated tones, over Klatt synthesized vowels, to natural vowels. In the first case, we study the FFR in response to the modulation frequency. For the other two, we study the FFR to the fundamental frequency of the voice. Second, we compare response SNRs across different frequency ranges, i.e. around 100, 150 or 200 Hz. Third, we study how intonation, i.e. the direction of variation of the fundamental frequency, affects the response SNR. We considered three cases: upward, flat, or downward intonation. FFRs are measured with 64 channel EEG and processed with a Fourier Analyzer. Data collection for this study is ongoing and preliminary results will be presented at the conference. Acknowledgements: This research is funded by FWO (Research foundation Flanders) within the framework of the TBM-project LUISTER (T002216N) and jointly by Cochlear Ltd. and Flanders Innovation & Entrepreneurship (formerly IWT), project 50432. Financial support was also provided by an SB PhD fellowship from FWO to Jana Van Canneyt.status: publishe