Some observations on ultrasonic perception in man.
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Hearing↗
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Results for “Pitch Perception”
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Hearing aid troubleshooting based on patients' descriptions.
Clinical audiologists were surveyed to determine the terms that their patients use to describe their reaction to hearing aid fitting problems. From this survey, a vocabulary of 40 frequently reported terms was developed. A second survey of hearing aid fitting experts was conducted to determine their methods of troubleshooting a hearing aid fitting when the patient reports one of the frequently reported terms. There was a high degree of agreement among the 24 experts. Principal components analysis resulted in ten components that explained 90.8% of the variance in the experts' responses. These results can be applied as an expert system for fine-tuning hearing aid fittings.
Correction of Hearing Impairment↗
[Autoradiography study of the uptake of 3H-2-deoxyglucose in the inner ear in normal and unilaterally sympathectomized albino rats].
Using the autoradiographic technique for water-soluble substances, the uptake of 3H-2-deoxyglucose (2-DG) was measured in the inner ear tissue. The experiments were performed on 26 albino rats (22-27 days). 10 microCi/g b.w. of 2-DG were applied i.v. and the control group was immediately kept in the Camera silens in darkness. The main group was exposed to pink noise (50 Hz - 10 kHz of 60-110 dB). 8 unilaterally sympathectomised animals were exposed to pink noise of different intensity after 24h. The highest uptake of 2-DG independent of the intensity of noise was observed in the cochlear lateral wall (stria vasc., sp. lig., sp. prominentia) in the basal turn and decreased to the apical turn. The uptake in the lateral wall increased from 30-40 dB to 60dB and decreased from 60 to 80 dB exposure. The region of the inner hair cells was clearly marked by 80 dB. With increasing intensity of noise exposure, 2-DG uptake in the spiral ganglion increased continually. Unilateral sympathectomy did not result in any significant difference in the uptake of 2-DG. Therefore, the hypothesis that the decrease of 2-DG uptake in the lateral wall may be due to sympathico-adrenergic vasoconstriction is not verified by our results.
Acoustic Stimulation↗
[The promontory test and electrocochleography in deafness caused by mumps].
Contradictory histological findings in patients with deafness following mumps led us to conduct electrophysiological investigations. Promontory testing (PT) and measurement of cochlear microphonics (CM) enabled us to distinguish between neural and sensory deafness. On the basis of a careful history and serological tests in 19 cases of unilateral deafness we found that the hearing loss was probably caused by mumps. In all patients except one auditory sensations could be obtained by electric stimulation of the acoustic nerve whereas no CM were detectable even with strong stimuli of 100 dB tonepips. In view of the electrophysiological findings, doubt is cast on the neural genesis of deafness following mumps as assumed by Lehnhardt (1962).
Audiometry, Evoked Response↗
Status praesens: cochlear implant. UIA-KULeuven-Forelec.
The authors review some basic anatomy and physiology of the auditory system as an introduction to the principles of cochlear implantation. A detailed description of the UIA-KUL-Forelec implant (LAURA) is given.
Animals↗
[Binaural summation of the ipsilateral and contralateral acoustic stapedius reflex (author's transl)].
The binaural summation of the simultaneous contra- and ipsilateral acoustic stapedius reflexes was examined in 20 normal-hearing patients. In these patients, the effect of summation was most pronounced with subthreshold intensities. A contralateral reflex was increased by ipsilateral intensities 8 db below threshold. A reflex could also be elicited by binaural intensities which were contra- and ipsilaterally 4 db below threshold. As a result of our studies, we recommend a revision of the definition of a positive Metz-recruitment. Because of possible binaural summation effects, the absolute value of the contralateral stapedius reflex threshold should not exceed 105 db HL in spite of possible sensorineural hearing loss.
Acoustic Impedance Tests↗
Auditory capabilities of patients implanted with the House single-channel cochlear implant.
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Audiometry↗
Pure tone habituation gradients based on responsiveness to electrical stimuli.
Previous study demonstrated that responsiveness to electrical stimulation of subcortical areas of cats was enhanced if preceded by a tone pip. Habituation occurred when the tone was repeatedly presented. In this study, the capacity for generalization of a habituated tone was measured by occasionally interpolating a tone of different frequency or intensity among a group of monotonously presented standard tones, measuring responsiveness in each case. The responses were: (1) the visual cortical evoked potential, (2) evoked EMG activity, and (3) evoked head movement. Frequency shifts and intensity increases produced recovery of responsiveness at latencies as short as 90 msec, while decreases had no effect on recovery. Responsiveness increased with degree of frequency shift up to 576 Hz, but showed no further increase for greater shifts up to 2304 Hz. A shift of 16 Hz was effective, comparable to behavioral thresholds for frequency discrimination. Thus, these gradients agreed with the form predicted on the basis of central fatigue models of habituation and the bandwidth of the eighth nerve fibers.
Animals↗
[Selectivity of afterdischarges of medial geniculate body neurons with regard to the characteristics of acoustic stimuli in the cat].
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Animals↗
Auditory fusion in children.
"Auditory fusion" was defined in terms of a listener's ability to distinguish paired acoustic events from single acoustic events. Children from the ages of 3-12 years listened to 270 pairs of tones controlled for frequency, intensity, and duration. Stimuli consisted of numerous pairs of tone pulses, separated by interpulse intervals that varied systematically from 0 through 40 msec. Results indicate that (a) auditory fusion improves rapidly and in an orderly fashion between 3 and 8 years of age, (b) signal intensity affects the fusion point, and (c) stimulus frequency--253 hertz through 4,000 hertz, at 5-octave intervals--does not affect the fusion point.
Auditory Perception↗
Electrodermal orienting activity in children with Down syndrome.
The elicitation and habituation of electrodermal orienting responses to auditory stimuli of 19 children with Down syndrome and a control group, an age and sex-matched sample of children without mental retardation were compared. Stimuli were ten 2-second 80 dB, 1000 Hz tones followed by a test tone (80 dB, 500 Hz). Children with Down syndrome gave electrodermal orienting responses of a lower amplitude than did the children in the control group. Both groups showed habituation of their responses. No significant differences were found between groups in either skin conductance levels or frequency of nonspecific responses. Overall, children with Down syndrome showed electrodermal hyporesponsivity in their orienting responses to the stimuli.
Acoustic Stimulation↗
[Loudness scaling. A procedure for quantitative recruitment detection].
Direct loudness scaling has been known as an audiological tool for about four decades. Although numerous publications have shown its clinical importance, loudness scaling has not been used in audiology and hearing aid fitting until now. This might be due to the lack of audiometers equipped with loudness scaling devices as well as missing evidence for its clinical applicability. In this study normal data for a single-step direct scaling procedure were established and loudness determinations of 105 patients with sensorineural hearing losses collected. The results show that normal level loudness functions exhibit very similar shapes for narrow band stimulation in the frequency range of 500 to 4000 Hz. However, loudness scaling is affected by the gender of the subjects: females scale systematically louder than do males. In hearing-impaired subjects the slopes of the level loudness functions tend to decrease with increasing hearing loss, indicating negative recruitment. This holds particularly true in the high-frequency range, e.g. at 4000 Hz. Our long-term experience with single-step direct loudness scaling has proven its clinical feasibility in typical patients of an audiology unit. Loudness scaling will prove useful for the localization of hearing impairments, as it can be employed as a quantitative indicator of recruitment without any restrictive preconditions. In addition, it allows the evaluation of hearing aids and cochlear implants by frequency-specific gain measurement.
Audiometry, Pure-Tone↗
Automatic change detection: does the auditory system use representations of individual stimulus features or gestalts?
The effects of global and feature-specific probabilities of auditory stimuli were manipulated to determine their effects on the mismatch negativity (MMN) of the human event-related potential. The question of interest was whether the automatic comparison of stimuli indexed by the MMN was performed on representations of individual stimulus features or on gestalt representations of their combined attributes. The design of the study was such that both feature and gestalt representations could have been available to the comparator mechanism generating the MMN. The data were consistent with the interpretation that the MMN was generated following an analysis of stimulus features.
Adult↗
Effects of pleasant and unpleasant ambient odors on human voice pitch.
The perception of odors is well identified as having strong emotional correlates. It is also well known that the acoustic characteristics of the voice differ according to the emotional state. This study compared some acoustic features of the voice of 18 subjects reading the same text in pleasant (lavender) and unpleasant (pyridine) ambient odor conditions. The results revealed that the pitch of the voice was higher in the pleasant than in the unpleasant condition. These findings are consistent with the hypothesis of local and functional convergences of encoding vocal emotion and hedonic perception of odors.
Adult↗
Perceptual interaction between carrier periodicity and amplitude modulation in broadband stimuli: a comparison of the autocorrelation and modulation-filterbank model.
Recent temporal models of pitch and amplitude modulation perception converge on a relatively realistic implementation of cochlear processing followed by a temporal analysis of periodicity. However, for modulation perception, a modulation filterbank is applied whereas for pitch perception, autocorrelation is applied. Considering the large overlap in pitch and modulation perception, this is not parsimonious. Two experiments are presented to investigate the interaction between carrier periodicity, which produces strong pitch sensations, and envelope periodicity using broadband stimuli. Results show that in the presence of carrier periodicity, detection of amplitude modulation is impaired throughout the tested range (8-1000 Hz). On the contrary, detection of carrier periodicity in the presence of an additional amplitude modulation is impaired only for very low frequencies below the pitch range (<33 Hz). Predictions of a generic implementation of a modulation-filterbank model and an autocorrelation model are compared to the data. Both models were too insensitive to high-frequency envelope or carrier periodicity and to infra-pitch carrier periodicity. Additionally, both models simulated modulation detection quite well but underestimated the detrimental effect of carrier periodicity on modulation detection. It is suggested that a hybrid model consisting of bandpass envelope filters with a ripple in their passband may provide a functionally successful and physiologically plausible basis for a unified model of auditory periodicity extraction.
Adult↗
Auditory abnormalities in autism: toward functional distinctions among findings.
Recently, findings on a wide range of auditory abnormalities among individuals with autism have been reported. To date, functional distinctions among these varied findings are poorly established. Such distinctions should be of interest to clinicians and researchers alike given their potential therapeutic and experimental applications. This review suggests three general trends among these findings as a starting point for future analyses. First, studies of auditory perception of linguistic and social auditory stimuli among individuals with autism generally have found impaired perception versus normal controls. Such findings may correlate with impaired language and communication skills and social isolation observed among individuals with autism. Second, studies of auditory perception of pitch and music among individuals with autism generally have found enhanced perception versus normal controls. These findings may correlate with the restrictive and highly focused behaviors observed among individuals with autism. Third, findings on the auditory perception of non-linguistic, non-musical stimuli among autism patients resist any generalized conclusions. Ultimately, as some researchers have already suggested, the distinction between impaired global processing and enhanced local processing may prove useful in making sense of apparently discordant findings on auditory abnormalities among individuals with autism.
Auditory Perceptual Disorders↗
Infants require low-frequency energy to hear the pitch of the missing fundamental.
The present experiment assessed 7- to 8-month-old infants' perception of pitch for harmonic tonal complexes containing either low- or high-frequency energy. In a visually reinforced, operant head turn procedure, infants first learned to discriminate two harmonic tonal complexes based on missing fundamental frequencies of 160 and 200 Hz. After learning this basic task, infants were presented with spectrally varying harmonic tonal complexes that contained either resolvable, low-frequency energy, or unresolvable, high-frequency energy. Infants learned to categorize the low-frequency signals according to the pitches of their missing fundamental frequencies but failed to categorize the high-frequency signals. These results suggest that infants require low-frequency, resolvable energy to hear the pitch of the missing fundamental.
Child Development↗
Pitch motion with random chord sequences.
Perception of global pitch motion was studied through psychoacoustic experiments with random chord sequences. Chords contained either six or eight (fixed) tone elements, being sinusoidal, sawtooth-like, or Shepard tones, which were either on or off according to a probability controlled by the experimenter. Sequences of 2, 4, 5, or 8 chords were used. Identification by subjects of the perceived direction of overall pitch motion (up or down) was found to be well accounted for by a model in which the ultimate pitch motion percept is given by a sum of contributions from selected element transitions--that is, transitions between adjoining tone elements in successive time frames only. In its simplest form, this dipole contribution model has only one free parameter, the perceptual noise for an element transition, which was estimated for various acoustic tone representations and chord arrangements. Results of two experiments, which were carried out independently in two different laboratories, are reported.
Adult↗