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Results for “Sound Spectrography”

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At least 289 records · Page 16Linked to original sources

PubMed2006

Temperature dependence of anuran distortion product otoacoustic emissions.

To study the possible involvement of energy-dependent mechanisms in the transduction of sound within the anuran ear, distortion product otoacoustic emissions (DPOAEs) were recorded in the northern leopard frog over a range of body temperatures. The effect of body temperature depended on the stimulus levels used and on the hearing organ under investigation. Low-level DPOAEs from the amphibian papilla (AP) were reversibly depressed for decreased body temperatures. Apparently, DPOAE generation in the AP depends on metabolic rate, indicating the involvement of active processes in the transduction of sound. In contrast, in the other hearing organ, the basilar papilla (BP), the effects of body temperature on DPOAEs were less pronounced, irrespective of the stimulus levels used. Apparently, metabolic rate is less influencing DPOAE generation. We interpret these results as evidence that no amplifier is involved in sound transduction in the BP. The passive functioning of the anuran BP would place this hearing organ in a unique position within tetrapod hearing, but may actually be beneficial to ectothermic species because it will provide the animal with a consistent spectral window, regardless of ambient or body temperature.

Animals↗

PubMed2003

Vocal individual discrimination in Japanese monkeys.

The present study determines which features of the coo call are used by Japanese monkeys Macaca fuscata for vocal individual discrimination. First, two female Japanese monkeys were trained to discriminate conspecific individuals vocally, using an operant conditioning. Using as stimuli three unknown individuals with 30 calls per individual, the two monkeys succeeded in discriminating new call exemplars from the three stimulus individuals. A discriminant analysis performed on calls used as stimuli indicated that start frequency of the fundamental and call duration were variables that can differentiate individuals efficiently. Then, playbacks of acoustically modified signals were used to indicate which vocal features are used by monkeys for the individual discrimination. Stimuli signals containing modified pitch or duration, or filtered so as to keep only the fundamental component, were tested. Results indicated that Japanese monkeys use multiple acoustical cues to perform vocal individual discrimination, including at least pitch, call duration, and harmonics. However, harmonics seem to be less important for discrimination than pitch and call duration.

Acoustic Stimulation↗

PubMed2004

A comparison of buttress drumming by male chimpanzees from two populations.

Wild chimpanzees ( Pan troglodytes) produce low-frequency sounds by hitting the buttresses and/or trunks of trees. This "buttress drumming" occurs in discrete bouts that may be integrated into the phrase sequence of the chimpanzee's long-distance vocalization, the "pant hoot." The aim of this study was to investigate whether regional variation exists in the drumming behavior of male chimpanzees from Kibale National Park (Kanyawara community), Uganda, and Taï National Park, Ivory Coast. Recordings were made during a 6-month field season at Taï in 1990, and a 12-month field season at Kanyawara in 1996-1997. Acoustic analysis revealed the following: (1) Kanyawara males drummed significantly less frequently in conjunction with a pant hoot or hoot than did Taï males; (2) drumming bouts by Kanyawara males included significantly fewer beats, and were significantly shorter in duration, than those of Taï males; these differences disappeared when only those bouts produced in conjunction with a call were compared; (3) when Kanyawara chimpanzees did call and drum together, they tended to integrate drumming into the vocalization at a later point than did Taï males; and (4) individual differences in the temporal patterning of drumming bouts were not apparent for Kanyawara males, whereas a previous analysis revealed individual differences among Taï males.

Animals↗

PubMed2004

Do Barbary macaques 'comment' on what they see? A first report on vocalizations accompanying interactions of third parties.

Primates acquire knowledge about relationships of third parties and group structure by monitoring their conspecifics. We show that Barbary macaques (Macaca sylvanus) utter specific vocalizations while monitoring interactions of other group members. As they did not direct other behaviours to the interacting group members, we provisionally termed these vocalizations 'vocal comments'. We investigated the acoustic properties of these comments and the social contexts in which they occurred. Most adult males and females of two studied groups produced low-amplitude calls when observing close contact interactions of other group members. The acoustic features of these calls varied with characteristics of the commented situation. Our results suggest that such calls might not be directed towards the agents of the commented situation, but towards other group members. The vocal comments may signal the caller's awareness of the observed interaction and possibly attract the attention of others to the situation.

Animals↗

PubMed2005

Measurements and theory of normal tracheal breath sounds.

We studied the mechanisms by which turbulent flow induces tracheal wall vibrations detected as tracheal breath sounds (TRBSs). The effects of flow rate at transitional Reynold's numbers (1300-10,000) and gas density on spectral patterns of TRBSs in eight normal subjects were measured. TRBSs were recorded with a contact sensor during air and heliox breathing at four flow rates (1.0, 1.5, 2.0, and 2.5 l/s). We found that normalized TRBSs were proportional to flow to the 1.89 power during inspiration and to the 1.59 power during expiration irrespective of gas density. The amplitude of TRBSs with heliox was lower than with air by a factor of 0.33 +/- 0.12 and 0.44 +/- 0.16 during inspiration and expiration, respectively. The spectral resonance frequencies were higher during heliox than air breathing by a factor of 1.75 +/- 0.2-approximately the square root of the reciprocal of the air/heliox wave propagation speed ratio. In conclusion, the flow-induced pressure fluctuations inside the trachea, which cause tracheal wall vibrations, were detected as TRBSs consist of two components: (1) a dominant local turbulent eddy component whose amplitude is proportional to the gas density and nonlinearly related to the flow; and (2) a propagating acoustic component with resonances whose frequencies correspond to the length of the upper airway and to the free-field sound speed. Therefore, TRBSs consist primarily of direct turbulent eddy pressure fluctuations that are perceived as sound during auscultation.

Adult↗

PubMed2006

Feature extraction for systolic heart murmur classification.

Heart murmurs are often the first signs of pathological changes of the heart valves, and they are usually found during auscultation in the primary health care. Distinguishing a pathological murmur from a physiological murmur is however difficult, why an "intelligent stethoscope" with decision support abilities would be of great value. Phonocardiographic signals were acquired from 36 patients with aortic valve stenosis, mitral insufficiency or physiological murmurs, and the data were analyzed with the aim to find a suitable feature subset for automatic classification of heart murmurs. Techniques such as Shannon energy, wavelets, fractal dimensions and recurrence quantification analysis were used to extract 207 features. 157 of these features have not previously been used in heart murmur classification. A multi-domain subset consisting of 14, both old and new, features was derived using Pudil's sequential floating forward selection (SFFS) method. This subset was compared with several single domain feature sets. Using neural network classification, the selected multi-domain subset gave the best results; 86% correct classifications compared to 68% for the first runner-up. In conclusion, the derived feature set was superior to the comparative sets, and seems rather robust to noisy data.

Aged↗

PubMed2006

Processing of affective speech prosody is impaired in Asperger syndrome.

Many people with the diagnosis of Asperger syndrome (AS) show poorly developed skills in understanding emotional messages. The present study addressed discrimination of speech prosody in children with AS at neurophysiological level. Detection of affective prosody was investigated in one-word utterances as indexed by the N1 and the mismatch negativity (MMN) of auditory event-related potentials (ERPs). Data from fourteen boys with AS were compared with those for thirteen typically developed boys. These results suggest atypical neural responses to affective prosody in children with AS and their fathers, especially over the RH, and that this impairment can already be seen at low-level information processes. Our results provide evidence for familial patterns of abnormal auditory brain reactions to prosodic features of speech.

Acoustic Stimulation↗

PubMed2006

Sound representation methods for spectro-temporal receptive field estimation.

The spectro-temporal receptive field (STRF) of an auditory neuron describes the linear relationship between the sound stimulus in a time-frequency representation and the neural response. Time-frequency representations of a sound in turn require a nonlinear operation on the sound pressure waveform and many different forms for this non-linear transformation are possible. Here, we systematically investigated the effects of four factors in the non-linear step in the STRF model: the choice of logarithmic or linear filter frequency spacing, the time-frequency scale, stimulus amplitude compression and adaptive gain control. We quantified the goodness of fit of these different STRF models on data obtained from auditory neurons in the songbird midbrain and forebrain. We found that adaptive gain control and the correct stimulus amplitude compression scheme are paramount to correctly modelling neurons. The time-frequency scale and frequency spacing also affected the goodness of fit of the model but to a lesser extent and the optimal values were stimulus dependent.

Acoustic Stimulation↗

PubMed2006

Effects of lexical prosody and word familiarity on lexical access of spoken Japanese words.

Lexical prosody (e.g., stress and pitch accent) has been shown to constrain lexical activation of spoken words in various languages. In the present study, whether or not the constraint of lexical prosody is affected by word familiarity in lexical access of Japanese words was examined using a cross-modal priming task. The stimuli were pairs of prosodically different homophones (minimal accent pairs). When the targets were more familiar members of minimal accent pairs, the responses were facilitated by prior presentations of primes that were prosodically different homophones of the targets, suggesting that lexical prosody did not constrain lexical activation. In contrast, when less familiar members of minimal accent pairs were used as the targets, the prosodically different homophones did not facilitate the responses to the targets. These results suggest that the constraint of lexical prosody is not so strong but is affected by the factor of word relative familiarity.

Adult↗

PubMed2006

Pitch cues for the recognition of yes-no questions in French.

Linguistic studies of the intonation of Yes-No questions in French show that, in questions containing more than two stress groups, interrogative intonation is characterized by a sequence of lowered pitches or downstepped tones which precede the final rise. The gating paradigm was used here to determine whether subjects listening to French NP utterances containing three stress groups could indicate whether the utterance was an statement or a question before the final rise was heard. Although the task was difficult, findings indicate that listeners can in fact to a certain extent, recognize with mid confidence ratings, the intonational device of a question while they were hearing the downstepped tones preceding the final rise.

Adult↗

PubMed2007

Intonation and emotion in autistic spectrum disorders.

The classic picture of an autistic individual includes an impoverished ability to interpret or express emotion. The prosody of spoken language in autistic children is thought to lack emotional content. In this study, the verbal intonation of children with autism was examined and compared to that of children with Asperger Syndrome (AS) and normal controls (ctrl). Utterances elicited by repetition and by spontaneous story completion were analyzed by quantifying phonetic features (pitch, amplitude, and length) and comparing them to subjective ratings of produced emotion (happy, sad or angry). Since the most consistent phonetic correlate of these emotional targets has been demonstrated to be pitch range, speakers with autistic spectrum disorders were expected to have decreased pitch range; however in the repetition task, autistic subjects actually had a larger pitch range than the other groups. Other measures of intonation including amplitude, duration, and location of pitch peak revealed defects that are more complex than predicted. In spontaneous speech, autistic subjects performed more poorly on both phonetic targets and subjective ratings than ctrls, and AS subjects fell between autistics and normals.

Adolescent↗

PubMed2005

Acoustic aspects of the formation of speech in children in the third year of life.

This study covers the third year of life as part of a longitudinal investigation of the establishment of speech in Russian children performed on the basis of listener, phonetic, and instrumented acoustical analysis. The present report addresses the establishment of those additional acoustic and phonetic characteristics in children's speech which allow speech recognition. This is the first instrumented analysis in Russian children with statistical assessment of the dynamics of vowel formants in children's words, of the establishment of characteristics (stress, lack of stress), opposition (palatalization, lack of palatalization of consonants), and voice onset time for plosive consonants. The results showed that recognition of children's words by listeners with a high probability of success resulted from the formation of a system of acoustically stable properties in the children's speech which together provide informational adequacy for verbal communication.

Adult↗

PubMed2005

The role of the flabellar and ellipsoid bodies of the central complex of the brain of Drosophila melanogaster in the control of courtship behavior and communicative sound production in males.

The role of flabellar and ellipsoid bodies of the central complex of the brain of Drosophila melanogaster males in controlling courtship behavior and the accompanying sound production was studied by comparative analysis of the characteristics of courtship and singing in wild-type flies and individuals of five mutant lines with different anatomical defects in these parts of the brain. Investigations were performed using the following fly lines: Canton S (wild-type, controls), ebo(KS263), with defects only in the ellipsoid bodies, and ebo(1041), ceb(849), ceb(892), and cba(KS96), with different levels of abnormality in both parts of the central complex. The data obtained here indicated that the flabellar and ellipsoid bodies are involved in: 1) maintaining a high level of courtship activity; 2) regulating the precision of male movements while following females; 3) in controlling the nature and stability of the sound elements from which communicative signals are constructed; 4) in regulating the rhythmic structure of signals dependent on the stability of pacemakers function; 5) establishing the relationship between behavior and the context in which it occurs.

Animal Communication↗

PubMed2005

Some problems in the measurement of the frequency-resolving ability of hearing.

Despite the detailed development of masking methods for measurement of the frequency selectivity of hearing, these measurements are hardly used for diagnostic purposes because they are time-consuming and because of the uncertain extrapolation of the results to the perception of complex spectral patterns. A method for the direct measurement of the spectral resolving ability of hearing using test signals with rippled spectra is proposed. These measurements showed 1) that the resolving ability of the auditory system in terms of discriminating complex spectra is greater than that suggested by the acuity of auditory frequency filters; 2) that changes in the acuity of frequency auditory filters associated with sound intensity hardly affect the ability to resolve complex spectra; 3) that the effects of interference on frequency-resolving ability do not lead to decreases in the spectral contrast of signals due to superimposition of noise.

Audiology↗

PubMed2006

Vocal dysperiodicities estimation by means of adaptive long-term prediction.

An adaptive formulation of the long-term bidirectional linear predictive analysis is proposed in the context of the acoustic assessment of disordered speech. Vocal dysperiodicities are summarized by means of a signal-to-dysperiodicity ratio (SDR) marker. It is shown that performing an adaptive forward and backward long-term linear prediction of each speech sample and retaining the minimal prediction error energy as a cue of vocal dysperiodicity results in an SDR that correlates with the perceived degree of hoarseness. The coefficients of the time-varying long-term linear predictive model are estimated by means of the recursive least squares algorithm. The corpora comprise sustained vowels and French sentences produced by male and female normophonic and dysphonic speakers. A perceptual assessment of speech samples, which rests on comparative judgments, is used to evaluate the ability of the acoustic marker to predict subjective measures of voice quality. Experimental results show that the adaptive approach gives rise to high correlations for sustained vowels as well as for sentences.

Case-Control Studies↗

PubMed2006

Neonatal pain analyzer: development and validation.

We developed a pain analyzer (ABC analyzer) to perform automatic acoustic analysis of neonatal crying and to provide an objective estimate of neonatal pain. The ABC analyzer uses a validated pain scale (ABC scale) based on three acoustic parameters: pitch frequency, normalized RMS amplitude, and presence of a characteristic frequency- and amplitude-modulated crying feature, defined as "siren cry". Here we assessed the reliability of the analyzer. We enrolled 57 healthy neonates. Each baby was recorded with a video camera during heel prick. Pain intensity was evaluated using a validated scale [Douleur Aigue du Nouveau-Né (DAN) scale] and the analyzer and the two scores were compared. We found a statistically significant concordance between the DAN score and ABC analyzer score (p < 0.0001). The ABC analyser is a novel approach to cry analysis that should now have its properties carefully evaluated in a series of studies, just as is necessary in the development of any other pain measurement tool.

Acoustics↗

PubMed1995

Constancy and normalization in the perception of Voice Offset Time as a cue for preaspiration.

It is a well-established fact that the realization of individual speech segments is heavily dependent on context. One factor, temporal organization, has been shown to affect numerous speech cues, especially those which are defined in the temporal domain. Theories of speech perception have adopted two different views of the nature of these contextual effects. On the one hand it has been hypothesized that the listener normalizes by taking account of the context. On the other hand it has been hypothesized that higher-order invariants, e.g. speech segment ratios, are sufficient cues for the relevant temporal contrasts, thus obviating the need for mechanisms of normalization. The present series of experiments investigates the merits of these opposing theoretical positions. The experiments involve Voice Offset Time as a cue for preaspiration in Icelandic. The results indicate that durational ratios can, for the most part, function as higher-order invariants for the perception of preaspiration.

Adult↗

PubMed1982

Frequency analysis approach to the origin of the first and second heart sounds.

Catheter-tipped micromanometers were used to simultaneously record left ventricular and aortic pressures, and left ventricular and aortic internal phonocardiograms in order to determine if they had a common mode of origin and propagation. Spectrographic analysis showed that even with high-pass filtration the phonocardiogram obtained with a commonly used system (Millar) contained large amounts of energy in the subaudible frequency range (below 40 Hz). It was possible to derive close facsimiles of the phonocardiograms by double differentiation of the corresponding pressure pulse and conversely to derive the pressure pulse by double integration of the phonocardiograms. The propagation velocities of the first heart sound, second heart sound, and the foot of the aortic pressure pulse were found to be similar and were respectively, 4.3 +/- 0.2, 4.6 +/- 0.3, and 4.2 +/- 0.2 m/sec (+/- SE). These data support the concept that the low frequency pressure variations produced by the heart, which predominate in the left ventricular and aortic pressure pulse waveforms, are generated and propagated in the same manner as the high frequency pressure variations, which are the first and second heart sounds.

Animals↗