Early maturation of frequency-following responses to voice pitch in infants with normal hearing.
(2011)
Journal - Perceptual and motor skills (United States )
Abstract :
Neural plasticity of pitch processing mechanisms at the human brainstem, as reflected by the scalp-recorded frequency-following response (FFR) to voice pitch, has been reported for normal-hearing adults. Characteristics and maturation of such a response during the first year of life have remained unclear. The purpose of this study was to examine the characteristics of FFR to voice pitch in normal-hearing infants and to make a direct comparison with adults using the same stimulus and recording parameters. 9 infants and 9 adults were recruited. A Chinese monosyllable that mimics the English vowel /i/ with a rising pitch was used to elicit the FFR to voice pitch. The results demonstrated that infant FFRs showed slightly larger Pitch Strength but comparable Frequency Error, Slope Error, and Tracking Accuracy to those obtained from adults. Early maturation of FFRs was also observed in the infants starting from 1 to 3 mo. of age.
| ISSN : | 0031-5125 |
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| Mesh Heading : | Adult Brain Stem Electroencephalography Evoked Potentials, Auditory, Brain Stem Female Humans Infant Male Reference Values Signal Processing, Computer-Assisted Speech Perception Young Adult physiology |
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| Mesh Heading Relevant : | Child Psychology Language Development Sound Spectrography Speech Acoustics Voice Quality physiology physiology |
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Exponential modeling of human frequency-following responses to voice pitch.
(2011)
Journal - International journal of audiology (England )
Abstract :
Recent studies have shown that the frequency-following response (FFR) to voice pitch can be a useful method to evaluate the signal-processing mechanisms and neural plasticity in the human brainstem. The purpose of this study was to examine the quantitative properties of the FFR trends with an exponential curve-fitting model.FFR trends obtained with increasing number of sweeps (up to 8000 sweeps) at three stimulus intensities (30, 45, and 60 dB nHL) were fit to an exponential model that consisted of estimates of background noise amplitude, asymptotic response amplitude, and a time constant. Five objective indices (Frequency Error, Slope Error, Tracking Accuracy, Pitch Strength and RMS Ratio) were used to represent different perspectives of pitch processing in the human brainstem. Study Sample: Twenty-three native speakers (16 males; age = 24.7 ± 2.1 years) of Mandarin Chinese were recruited.The results demonstrated that the exponential model provided a good fit (r(2) = 0.89 ± 0.10) to the FFR trends with increasing number of sweeps for the five objective indices.The exponential model, combined with the five objective indices, can be used for difficult-to-test patients and may prove to be useful as an assessment and diagnostic method in both clinical and basic research efforts.
Effects of silent interval on human frequency-following responses to voice pitch.
(2011)
Journal - The Journal of the Acoustical Society of America (United States )
Abstract :
Human frequency-following responses (FFRs) to voice pitch have provided valuable information on how the human brain processes speech information. Recordings of the FFR to voice pitch, however, may overlap when insufficient silent intervals are used. To determine the shortest silent interval that can be used with no overlap between adjacent response waveforms, FFRs were recorded from 12 Chinese adults using a wide range of silent intervals. The stimulus token was a Chinese monosyllable with a rising pitch of 117-166 Hz and a duration of 250 ms. A high stimulus intensity at 70 dB SPL was used to maximize overlaps in the response waveforms. A total of seven silent intervals, ranging from the full length of the stimulus duration down to approximately half period of the fundamental frequency of the stimulus token, were administered at a random order across participants. Two distinct methods (Hilbert transform and root-mean-square amplitudes) were used to delineate the envelopes and overlaps of the response waveforms. A one-way repeated measures analysis of variance was significant (p = 0.038) in defining the magnitude of overlaps for the 10 ms pre-stimulus interval. The results indicated the shortest silent interval that could be used without compromising the response is between 35 and 45 ms.
Relative power of harmonics in human frequency-following responses associated with voice pitch in American and Chinese adults.
(2011)
Journal - Perceptual and motor skills (United States )
Abstract :
When the fundamental frequency (f0) is removed from a complex stimulus, the pitch of the f0 is still perceived by the listener. Through the use of the scalp-recorded frequency-following response, this study examined the relative contributions of thef0 and its harmonics in pitch processing by systematically manipulating the speech stimulus to remove component frequencies. 12 American and 12 Chinese adults were recruited. There were statistically significant effects of pitch strength and frequency error for the experimental-condition factor. There were significantly larger responses to the harmonics-only conditions than those obtained in the f0-only and control conditions. No statistically significant difference was observed between the two groups of participants. These findings indicate that neural responses associated with individual harmonics dominate the pitch processing in the human brainstem, irrespective of whether the listener's native language is nontonal or tonal.
Electrically evoked auditory steady-state responses in a guinea pig model: latency estimates and effects of stimulus parameters.
(2008)
Journal - Audiology & neuro-otology (Switzerland )
Abstract :
Cochlear implant speech processors typically extract envelope information of speech signals for presentation to the auditory nerve as modulated trains of electric pulses. Recent studies showed the feasibility of recording, at the scalp, the electrically evoked auditory steady-state response using amplitude-modulated electric stimuli. Sinusoidally amplitude-modulated electric stimuli were used to elicit such responses from guinea pigs in order to characterize this response. Response latencies were derived to provide insight regarding neural generator sites. Two distinct sites, one cortical and another more peripheral, were indicated by latency estimates of 22 and 2 ms, respectively, with the former evoked by lower (13-49 Hz) and the latter by higher (55-320 Hz) modulation frequencies. Furthermore, response amplitudes declined with increasing carrier frequency, exhibited a compressive growth with increasing modulation depths, and were sensitive to modulation depths to as low as 5%.(c) 2007 S. Karger AG, Basel
| ISSN : | 1421-9700 |
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| Mesh Heading : | Acoustic Stimulation Animals Deafness Electric Stimulation Evoked Potentials, Auditory Guinea Pigs Models, Animal Neomycin Otitis Media Reaction Time Software Sound chemically induced |
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| Mesh Heading Relevant : | prevention & control physiology physiopathology physiology |
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Electrically evoked auditory steady-state responses in Guinea pigs.
(2007)
Journal - Audiology & neuro-otology (Switzerland )
Abstract :
Most cochlear implant systems available today provide the user with information about the envelope of the speech signal. The goal of this study was to explore the feasibility of recording electrically evoked auditory steady-state response (ESSR) and in particular to evaluate the degree to which the response recorded using electrical stimulation could be separated from stimulus artifact. Sinusoidally amplitude-modulated electrical stimuli with alternating polarities were used to elicit the response in adult guinea pigs. Separation of the stimulus artifact from evoked neural responses was achieved by summing alternating polarity responses or by using spectral analysis techniques. The recorded response exhibited physiological response properties including a pattern of nonlinear growth and their abolishment following euthanasia or administration of tetrodotoxin. These findings demonstrate that the ESSR is a response generated by the auditory system and can be separated from electrical stimulus artifact. As it is evoked by a stimulus that shares important features of cochlear implant stimulation, this evoked potential may be useful in either clinical or basic research efforts.Copyright 2007 S. Karger AG, Basel.
| ISSN : | 1421-9700 |
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| Mesh Heading : | Acoustic Stimulation Anesthetics, Local Animals Artifacts Auditory Perception Cochlear Implants Disease Models, Animal Electric Stimulation Evoked Potentials, Auditory Guinea Pigs Hearing Loss, Sensorineural Tetrodotoxin methods pharmacology drug effects chemically induced therapy pharmacology |
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| Mesh Heading Relevant : | physiology methods physiology physiopathology |
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