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PubMed1996

Amygdala central nucleus lesions attenuate acoustic startle stimulus-evoked heart rate changes in rats.

Amygdala central nucleus (CNA) lesions were used to test the hypothesis that stimulus-evoked heart rate changes can reflect the development of fear during acoustic startle testing. A 120-dB white noise startle stimulus produced freezing as well as phasic heart rate accelerations and decelerations, and an abrupt decrease in tonic heart rate, in sham-operated rats. These responses were all significantly reduced in CNA-lesioned rats. In contrast, an 87-dB stimulus elicited only significant phasic decelerations that were similarly attenuated by the CNA lesions. In a follow-up experiment, the CNA lesions also attenuated phasic cardiac decelerations evoked by a conditioned stimulus-like, 85-dB pure tone. The results support the contention (B. J. Young & R.N. Leaton, 1994) that heart rate changes can reflect fear conditioned during acoustic startle testing and, in addition, suggest that the amygdala mediates responses to nonsignal acoustic stimuli.

Acoustic Stimulation↗
PubMed1984

Strychnine increases acoustic startle amplitude but does not alter short-term or long-term habituation.

Theories of habituation have included an increase in postsynaptic inhibition as one possible mechanism underlying response decrement following repetitive stimulus presentation. In this study, the glycine antagonist strychnine (1.0 mg/kg, ip, 10 min pretreatment) was used to investigate the involvement of glycinergic neurons in the development and/or expression of short-term (within-session) habituation (Experiment 1) and long-term (between-sessions) habituation (Experiments 2 and 3) of the acoustic startle response in rats. Over a range of eliciting-stimulus intensities (95, 105, and 115 dB) and interstimulus intervals (3, 7, 13, and 27 s), strychnine markedly increased startle amplitude, relative to water injection, whereas it failed to attenuate the rate of within-session habituation (Experiment 1). In Experiment 2, rats that were exposed to daily sessions of startle-eliciting stimuli for 4 days and then tested on the fifth day showed lower overall levels of startle amplitude, relative to rats that had not received prior habituation training. Strychnine injected prior to the test session again increased startle amplitude but did not block the expression of between-sessions habituation. In Experiment 3, rats that were injected with either strychnine or water prior to each of three daily habituation training sessions and subsequently tested on Day 4 showed similar between-sessions habituation, relative to untrained rats that had received daily injections in the animal room. In summary, strychnine increased startle amplitude without affecting either within-session or between-sessions habituation of acoustic startle. These results emphasize the need to discern between drug effects on response amplitude per se and effects on response habituation. Furthermore, the data indicate that a buildup of inhibition in glycinergic neurons does not explain either within-session or between-sessions habituation of acoustic startle in rats. These results are discussed in light of current theories of habituation.

Acoustic Stimulation↗
PubMed1979

Temporal integration of acoustic stimulation obtained in reflex inhibition in rats and humans.

An acoustic stimulus (S1) presented just before reflex elicitation inhibits reflex expression. The present studies questioned whether inhibition provided by initial stimuli of various durations conforms to established temporal integration functions. Initial stimuli were noise bursts varying in duration (2, 20, or 200 msec) and intensity (55 or 85 dB). Eliciting stimuli (S2) for rats were intense tone bursts, which elicited the acoustic startle reflex, and for humans electrotactile stimuli to the forehead, which elicited the eye blink. Findings revealed that inhibition was greater with the 85-dB S1 stimulus and increased linearly with log increases in duration. These latter data suggest that the acoustic substrate for reflex inhibition has a long-time constant. There was one exception to this general finding. For seven (of nine) human subjects, inhibition declined when the duration of the 85-dB S1 was increased from 20 to 200 msec. Postexperimental questioning and video monitoring suggest that this anomaly resulted from a reflex enhancing arousal process.

Acoustic Stimulation↗
PubMed1993

A possible neuronal basis for representation of acoustic scenes in auditory cortex of the big brown bat.

Behavioural studies and field observations demonstrate that echolocating bats simultaneously perceive range, direction and shape of multiple objects in the environment as acoustic images derived from echoes. Cortical echo delay-tuned neurons contribute to the perception of object range, because focal inactivation of these neurons disrupts behavioural discrimination of range. We report here that response properties of delay-tuned neurons in the cortical tonotopic area of the bat, Eptesicus, transform the sequential arrival times of echoes with different delays into a concurrent, accumulating neural representation of multiple objects at different ranges. The sharpness of delay tuning systematically increases at each best delay in a subpopulation of these neurons while responses to echoes at different delays are accumulated. The resulting concurrent, multiresolution representation of echo delay corresponds to neural implementation of a common representation of images used in computational vision and may provide the basis for representing acoustic images of multiple objects as acoustic 'scenes'.

Acoustic Stimulation↗
PubMed2006

Conformational chemistry of surface-attached calmodulin detected by acoustic shear wave propagation.

A thickness shear-mode acoustic wave device, operated in a flow-through format, was used to detect the binding of ions or peptides to surface-attached calmodulin. On-line surface attachment of the protein was achieved by immobilisation of the biotinylated molecule via a neutravidin-biotin linkage onto the surface of the gold electrode of the detector. The interaction between calmodulin, and calcium and magnesium ions induced an increase in resonant frequency and a decrease in motional resistance, which were reversible on washing with buffer. Interestingly, the changes in resonant frequency and motional resistance induced by the binding were opposite to the normal operation of the detector. The response was interpreted as a decrease in surface coupling (partial slip at the liquid/solid interface) instigated by exposure of hydrophobic domains on the protein, and an increase in the thickness, and hence effective wavelength, of the acoustic device, corresponding to an increase in the length of calmodulin by 1.5 A. This result is consistent with the literature value of 4 A. In addition, the interaction of the protein with peptide together with calcium ions was detected successfully, despite the relatively low molecular mass of the 2-kDa peptide. These results confirm the potential of acoustic wave physics for the detection of changes in the conformational chemistry of monolayer of biochemical macromolecules at the solid/liquid interface.

Acoustics↗
PubMed2005

Sex-related acoustic changes in voiceless English fricatives.

This investigation is a comprehensive acoustic study of 4 voiceless fricatives (/f theta s /) in English produced by adults and pre- and postpubescent children aged 6-14 years. Vowel duration, amplitude, and several different spectral measures (including spectral tilt and spectral moments) were examined. Of specific interest was the pattern of normal development of the acoustic properties of fricatives and the nature of sex-specific patterns of fricative articulation in prepubescent children. Little evidence of amplitude or duration differences was found between speakers that was related to sex of the speaker. However, significant sex-specific differences in fricative articulation were found in all groups of speakers-even in the youngest children (ages 6-7 years)-although there was an indication that some of the acoustic differences between females and males is reduced or absent in the youngest children. Results from discriminant analysis demonstrated that a discriminant function based on the adult male tokens was generally better at classifying fricatives produced by male speakers than female speakers, regardless of age. This showed that sex-related differences (presumably a function of sex-linked vocal tract variation) were present even in the youngest speaker group. However, the classification accuracy of the female model showed a steady improvement with the increased age of the female speakers and may provide support for the claim that sex-related developmental differences may just be emerging in the youngest age group.

Adolescent↗
PubMed2005

Impact of aberrant acoustic properties on the perception of sound quality in electrolarynx speech.

A large percentage of patients who have undergone laryngectomy to treat advanced laryngeal cancer rely on an electrolarynx (EL) to communicate verbally. Although serviceable, EL speech is plagued by shortcomings in both sound quality and intelligibility. This study sought to better quantify the relative contributions of previously identified acoustic abnormalities to the perception of degraded quality in EL speech. Ten normal listeners evaluated the sound quality of EL speech tokens that had been acoustically enhanced by (a) increased low-frequency energy, (b) EL-noise reduction, and (c) fundamental frequency variation to mimic normal pitch intonation in relation to nonenhanced EL speech, normal speech, and normal monotonous speech (fundamental frequency variation removed). In comparing all possible combinations of token pairs, listeners were asked to identify which one of each pair sounded most like normal natural speech, and then to rate on a visual analog scale how different the chosen token was from normal speech. The results indicate that although EL speech can be most improved by removing the EL noise and providing proper pitch information, the resulting quality is still well below that of normal natural speech or even that of monotonous natural speech. This suggests that, in addition to the widely acknowledged acoustic abnormalities examined in this investigation, there are other attributes that contribute significantly to the unnatural quality of EL speech. Such additional factors need to be clearly identified and remedied before EL speech can be made to more closely approximate the sound quality of normal natural speech.

Female↗
PubMed2005

An across-frequency processing deficit in listeners with hearing impairment is supported by acoustic correlation.

It has been recently suggested that listeners having a sensorineural hearing impairment (HI) may possess a deficit in their ability to integrate speech information across different frequencies. When presented with a task that required across-frequency integration of speech patterns, listeners with HI performed more poorly than their normal-hearing (NH) counterparts (E. W. Healy & S. P. Bacon, 2002; C. W. Turner, S.-L. Chi, & S. Flock, 1999). E. W. Healy and S. P. Bacon (2002) also showed that performance of the listeners with HI fell more steeply when increasing amounts of temporal asynchrony were introduced to the pair of widely separated patterns. In the current study, the correlations between the fluctuating envelopes of the acoustic stimuli were calculated, both when the patterns were aligned and at various between-band asynchronies. It was found that the rate at which acoustic correlation fell as a function of asynchrony closely matched the rate at which intelligibility fell for the NH listeners. However, the intelligibility scores produced by the listeners with HI fell more steeply than the acoustic analysis would suggest. Thus, these data provide additional support for the hypothesis that individuals having sensorineural HI may have a deficit in their ability to integrate speech information present at different frequencies.

Auditory Perceptual Disorders↗
PubMed2006

Birth control pills and nonprofessional voice: acoustic analyses.

PURPOSE: Two studies are presented here. Study 1 was aimed at evaluating whether the voice characteristics of women who use birth control pills that contain different progestins differ from the voice characteristics of a control group. Study 2 presents a meta-analysis that combined the results of Study 1 with those from 3 recent studies that compared voices of women who use and do not use birth control pills. METHOD: In Study 1, voice samples from 30 women with no history of voice training, who use pills with different progestins (drospirenone, desogestrel, gestodene), and 10 women who do not use the pill were recorded at specific time points across the menstrual cycle and were analyzed acoustically. In Study 2, results from Study 1 were analyzed jointly with results from three recent studies, which used similar methodologies. RESULTS: Results of Study 1 did not reveal acoustic differences in sustained phonation of vowels across the pill groups and controls. Results of the meta-analysis performed in Study 2 indicated that pill users exhibited lower jitter and shimmer values on sustained vowels, whereas no difference of fundamental frequency was observed among women who use the pill. CONCLUSIONS: These results support findings from previous studies, which suggested that no adverse effect on voice was detected among nonprofessional speakers who use new-generation monophasic birth control pills, for the measures studied. Furthermore, results of the meta-analysis suggested that some acoustic properties of the voice, which are reflected in perturbation measures in sustained vowels, may be improved among women who use the pill.

Adult↗
PubMed1984

Teflon injection in 16 patients with paralytic dysphonia: perceptual and acoustic evaluations.

Sixteen patients with paralytic dysphonia were treated with Teflon injection in the paralyzed vocal fold. Trained voice pathologists rated the pre- and postinjection voices on a 5-point scale for each 11 voice characteristics. Among these, aphonia, breathiness, and hypofunction diminished significantly after injection. The perceptual evaluation was correlated with acoustic data from long-time-average spectrum analysis, fundamental frequency distribution analysis, and waveform perturbation analysis. In this acoustic assessment, systematic changes were found in the long-time-average spectra, which agreed well with the perceptual data. In 12 of 16 patients the voice was both perceptually and acoustically improved after Teflon injection.

Adult↗
PubMed1985

Acoustic and physiologic correlates of the voicing distinction in esophageal speech.

This study was designed to compare high- and low-intelligibility productions of /t/ and /d/ in esophageal speakers by using a combination of acoustic, perceptual, and physiologic measurements. Observations from these comparisons were incorporated into clinical strategies for modifying a single subject's low-intelligibility utterances. Acoustic comparison indicated that esophageal speakers used voice onset and phonation off-times but not vowel durations to differentiate /t/ and /d/ in high-intelligibility productions. Intraoral pressure measures during /t/ and /d/ production demonstrated excessively high intraoral pressures in both consonants for a low-intelligibility speaker and did not suggest systematic differences in intraoral pressure between /t/ versus /d/. Two weeks of biofeedback treatment with a low-intelligibility speaker were associated with a reduction in intraoral pressures for /t/ and /d/ productions, improved intelligibility, and changes in acoustic characteristics for /t/.

Acoustics↗
PubMed1989

Contralateral acoustic-reflex growth function in a patient with a cerebellar tumor: a case study.

The contralateral acoustic-reflex growth functions (ARGFs) for 500-Hz and 1000-Hz tonal activators were obtained pre- and postsurgery in a patient with a right cerebellar tumor. The acoustic-reflex magnitude was quantified as the change in equivalent air volume at the tympanic membrane during acoustic-reflex contraction. The presurgical ARGFs were shallow in the right ear and steep in the left ear at both activator frequencies. The postsurgical ARGFs were steep, bilaterally, reflecting a return to normal in the right ear. The implications with respect to the use of the ARGF measure in differential diagnosis are discussed.

Carcinoma, Squamous Cell↗
PubMed1990

Acoustical effects of endotracheal intubation.

Certain acoustical consequences of endotracheal intubation were examined in 13 male cardiovascular-surgery patients. Each subject recorded three tokens of a sustained vowel 1 day before intubation, 1 day after, upon discharge, and during a follow-up visit. Eight acoustical measures were obtained from the audio-recorded vowels: (a) mean fundamental frequency (Fo), (b) Fo standard deviation, (c) Fo perturbation quotient, (d) mean sound pressure level (SPL), (e) SPL standard deviation, (f) SPL perturbation quotient, (g) spectral flatness of the residue signal, and (h) coefficient of excess. Mean Fo, Fo standard deviation, mean SPL, SPL standard deviation, and coefficient of excess did not differ significantly across recording sessions, although certain predictable trends were apparent. Fo perturbation quotient, SPL perturbation quotient, and spectral flatness of the residue signal varied significantly across sessions, implying that these acoustical measures may be useful in the identification and monitoring of even minor intubation-related laryngeal trauma.

Adult↗
PubMed1975

Acoustic-reflex response to sustain signals.

Acoustic-reflex activity was observed for 10 normal-hearing young adults using three sustained activating signals: 500-Hz tone, 4000-Hz tone, and broad-band noise. Reflex activity was observed over a period of three to five minutes at activator levels of 5, 10, and 15 dB above individual acoustic-reflex thresholds. General findings were that (1) acoustic-reflex adaptation was present to some degree for all three activating signals, (2) the amount of reflex adaptation varied with the spectrum of activating signals (reflex adaptation was greatest for the 4000-Hz activator, less for the noise activator, and least for the 500-Hz activating signal), (3) the rate of reflex adaptation differed with activator spectrum (reflex-adaptation rate was relatively rapid for the 4000-Hz activator, slower for noise, and much slower for the 500-Hz activating signal), and (4) reflex adaptation did not appear to vary systematically with activating-signal level except for the 500-Hz activator, in which case reflex adaptation appeared to begin earlier in time and to be of greater magnitude as the activating-signal level was increased.

Acoustic Stimulation↗
PubMed1976

Anatomical and neuromuscular maturation of the speech mechanism: evidence from acoustic studies.

This paper surveys acoustic studies of speech development and discusses the data with respect to the anatomical and neuromuscular maturation of the speech mechanism. The acoustic data on various aspects of speech production indicate that the accuracy of motor control improves with age until adult-like performance is achieved at about 11 or 12 years, somewhat after the age at which speech sound acquisition usually is judged to be complete. Other topics of discussion are (1) problems in the spectrographic analysis of children's speech, (2) formant scale factors that relate children's and adults' data, and (3) identification and diagnosis of developmental disorders through acoustic analyses of speech sounds.

Acoustics↗
PubMed1978

Acoustic-reflex dynamics for pulsed signals.

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.

Acoustic Impedance Tests↗
PubMed1979

Effects of ethyl alcohol on the contralateral and ipsilateral acoustic reflex threshold.

Contralateral and ipsilateral acoustic reflex thresholds were measured in response to 500-, 1000-, and 2000-Hz pure tones after the ingestion of a 50% alcohol solution. Acoustic reflex threshold measurements were obtained preingestion and at blood-alcohol concentrations of 0.03 to 0.10% in 0.01% increments. A linear relationship existed between acoustic reflex threshold and blood-alcohol concentration, with the greatest shift at 0.10% being 11 dB for contralateral stimulation and 7 dB for ipsilateral. No frequency effects were found. Results can be explained by the anatomical differences in the contralateral and ipsilateral pathways.

Adult↗
PubMed1984

Acoustic differentiation of laryngeal, esophageal, and tracheoesophageal speech.

This investigation was designed to determine if a multivariate acoustic classifier could effectively discriminate group membership for 15 tracheoesophageal, esophageal, and laryngeal speakers. Seven intensity, 10 frequency, and 13 duration measures were quantified from recorded voice samples. Using principal components analysis, a subset of the 13 least redundant acoustic and temporal measures was systematically selected from the 30 original measures and analyzed singly and jointly in terms of its ability to discriminate among the three speaker groups. Discriminant function analysis revealed perfect categorization of the 45 subjects, indicating that the three methods of speech production are acoustically and temporally distinct from one another. The relative importance of the selected variables which, in combination, significantly differentiated the three groups is discussed in relation to physiologic differences among groups and clinical application for postlaryngectomy vocal rehabilitation.

Humans↗