Envelope and spectral frequency-following responses to vowel sounds

• Published in: Hearing research Vol. 245; no. 1; pp. 35 - 47
• Main Authors: Aiken, Steven J., Picton, Terence W.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-11-2008; Elsevier
• Subjects: Acoustic Stimulation; Adult; Auditory evoked potentials; Auditory Threshold - physiology; Biological and medical sciences; Cochlear Microphonic Potentials; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Electroencephalography - statistics & numerical data; Female; Fourier Analysis; Fourier analyzer; Frequency-following responses; Fundamental and applied biological sciences. Psychology; Humans; Male; Medical sciences; Non tumoral diseases; Otorhinolaryngology. Stomatology; Phonetics; Psychoacoustics; Speech envelope; Vertebrates: nervous system and sense organs; Vowel sounds; Young Adult; ABR; Frequency-following responses; FFR; Fourier analyzer; Speech envelope; Auditory evoked potentials; CM; Vowel sounds; ASSR; Harmonic; Response amplitude; Electrophysiology; Sound; Hearing; Formant; Vowel; Auditory evoked potential; Speech; Polarity; Harmonic distortion; Fundamental frequency
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/j.heares.2008.08.004

Frequency-following responses (FFRs) were recorded to two naturally produced vowels (/a/ and /i/) in normal hearing subjects. A digitally implemented Fourier analyzer was used to measure response amplitude at the fundamental frequency and at 23 higher harmonics. Response components related to the stimulus envelope (“envelope FFR”) were distinguished from components related to the stimulus spectrum (“spectral FFR”) by adding or subtracting responses to opposite polarity stimuli. Significant envelope FFRs were detected at the fundamental frequency of both vowels, for all of the subjects. Significant spectral FFRs were detected at harmonics close to formant peaks, and at harmonics corresponding to cochlear intermodulation distortion products, but these were not significant in all subjects, and were not detected above 1500
Hz. These findings indicate that speech-evoked FFRs follow both the glottal pitch envelope as well as spectral stimulus components.