Effects of Inter-Stimulus Interval on Speech-Evoked Frequency-Following Response in Elderly Adults.

Dongxin Liu,Jiong Hu,Jing Chen,Gabriella Musacchia,Ruijuan Dong,Shuo Wang

doi:10.3389/fnagi.2018.00357

Abstract

Background: The speech-evoked frequency following response (FFR) has shown to be useful in assessing complex auditory processing abilities and in different age groups. While many aspects of FFR have been studied extensively, the effect of timing, as measured by inter-stimulus-interval (ISI), especially in the older adult population, has yet to be thoroughly investigated.Objective: The purpose of this study was to examine the effects of different ISIs on speech evoked FFR in older and younger adults who speak a tonal language, and to investigate whether the older adults’ FFR were more susceptible to the change in ISI.Materials and Methods: Twenty-two normal hearing participants were recruited in our study, including 11 young adult participants and 11 elderly participants. An Intelligent Hearing Systems Smart EP evoke potential system was used to record the FFR in four ISI conditions (40, 80, 120 and 160 ms). A recorded natural speech token with a falling tone /yi/ was used as the stimulus. Two indices, stimulus-to-response correlation coefficient and pitch strength, were used to quantify the FFR responses. Two-way analysis of variance (ANOVA) was used to analyze the differences in different age groups and different ISI conditions.Results: There was no significant difference in stimulus-to-response correlation coefficient and pitch strength among the different ISI conditions, in either age groups. Older adults appeared to have weaker FFR for all ISI conditions when compared to their younger adult counterparts.Conclusion: Shorter ISIs did not result in worse FFRs from older adults or younger adults. For speech-evoked FFR using a recorded natural speech token that is 250 ms in length, an ISI of as short as 40 ms appeared to be sufficient and effective to record FFR for elderly adults.

Highlights

The frequency-following response (FFR) recorded from the human scalp is an electrophysiological potential which follows the periodicity of the stimuli (Moushegian et al, 1973)
The purpose of this study is to expand on our previous work on the speech-evoked FFR in older adults who speak a tonal language, and to examine the effect of different ISIs on the older adults’ FFR
The 40 ms ISI has been widely used in the FFR literature for Mandarin Chinese speech stimuli in younger adults (Krishnan et al, 2004, 2005; Jeng et al, 2011; Wang et al, 2016)

Summary

Introduction

The frequency-following response (FFR) recorded from the human scalp is an electrophysiological potential which follows the periodicity of the stimuli (Moushegian et al, 1973). Krishnan et al (2004, 2005) used four different Mandarin Chinese tones to evoke FFR in young adult native speakers of Mandarin to examine the effect of language background on pitch processing. Another application of FFR is to use a consonant-vowel (CV) complex, typically /da/, to evaluate various aspects of the auditory processing function, such as the effect of maturation (Anderson et al, 2010), auditory training (Song et al, 2008), music training (Musacchia et al, 2008), language and/or reading issues (Banai et al, 2009) and speech perception in noise (Banai et al, 2009). While many aspects of FFR have been studied extensively, the effect of timing, as measured by inter-stimulus-interval (ISI), especially in the older adult population, has yet to be thoroughly investigated

Methods

Results

Conclusion