Speech Evoked Auditory Brainstem Responses: A New Tool to Study Brainstem Encoding of Speech Sounds

Abstract

The neural encoding of speech sound begins in the auditory nerve and travels to the auditory brainstem. Non speech stimuli such as click or tone bursts stimulus are used to check the auditory neural integrity routinely. Recently Speech evoked Auditory Brainstem measures (ABR) are being used as a tool to study the brainstem processing of Speech sounds. The aim of the study was to study the Speech evoked ABR to a consonant vowel (CV) stimulus. 30 subjects with normal hearing participated for the study. Speech evoked ABR were measured to a CV stimulus in all the participants. The speech stimulus used was a 40 ms synthesized/da/sound. The consonant and vowel portion was analysed separately. Speech evoked ABR was present in all the normal hearing subjects. The consonant portion of the stimulus elicited peak V in response waveform. Response to the vowel portion elicited a frequency following response (FFR). The FFR further showed a coding of the fundamental frequency (F0) and the first formant frequency (F1). The results of the present study throw light on the processing of speech in brainstem. The understanding of speech evoked ABR has other applications both in research as well as in clinical purposes. Such understanding is specially important if one is interested in studying the central auditory system function.

Speech-Evoked Brainstem Response

“…However, additional studies have been initiated in numerous languages such as Arabic, Brazilian Portuguese, French, Greek, Hebrew, Indian, Japanese, and Persian [1,11,13,[22][23][24][25][26][27][28][29][30][31][32].…”

“…The syllable / da/ is most well known and applied more often in studies [11,13,15,22,25,28,29,32,36,39,45,47]. However, there are researchers who used disyllables as /baba/ [27] or even other syllables composed by consonant-vowel as /ba/ [23,30,31].…”

“…Besides that, another application of speech ABR can be in diagnosing and categorizing children with learning disability in different subgroups, assessing the effects of aging on central auditory processing of speech, and assessing the effects of central auditory deficits in hearing aid and cochlear implant users [11].…”

“…The component FFR is called sustained portion and seems to be elicited around 18-50 ms. This component reflects the encoding of periodic and harmonic structure of vowel sound related to harmonic vowels [11] and is also related to encoding of the elements of fundamental frequency and its modulations (first and second formants) [4,15].…”

Effects of Auditory Brainstem Response (ABR) on Measuring Children’s Auditory Functions: An Experimental Investigation

“…Sinha & Basavaraj (2010)'s paper investigates the speech evoked ABR to a consonant vowel stimulus. The total number of the participants of the study was thirty (30) subjects withJournal for the Study of English Linguistics ISSN 2329-7034 2013, Vol.…”