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At least 1,711 records · Page 95Linked to original sources
PubMed1997

Effects of pars flaccida on sound conduction in ears of Mongolian gerbil: acoustic and anatomical measurements.

This paper presents evidence on how the pars flaccida of the tympanic membrane affects the acoustic input to the middle and inner ear. Measurements of middle-ear acoustic input admittance and sound-pressure levels in both the ear canal and the middle-ear cavity were made in ears of eight gerbils before and after manipulations of the middle ear and tympanic membrane. The results are interpreted in terms of a model proposed by Kohllöffel [Hear, Res. 13(1984) 83-88]. The input-admittance measurements show that the pars flaccida of gerbil acts as a resonator with a resonance frequency of approx. 500 Hz. The admittance of this resonator appears in parallel with the input admittance of the pars tensa and its ossicular and cochlear load. At frequencies below the resonance, the pars flaccida admittance is compliance-like and its magnitude is comparable to that of the pars tensa and its load; consequently, the presence of pars flaccida increases the overall middle-ear input admittance and decreases the pressure difference across the tympanic membrane. At higher frequencies, the admittance of pars flaccida is mass-like and small in magnitude, and it has negligible influence on the overall middle-ear input admittance and the pressure difference across the tympanic membrane. These results suggest that the presence of pars flaccida reduces low-frequency acoustic input to the middle- and inner-ear and consequently decreases hearing sensitivity in this frequency range. Our measurements suggest that with a constant sound pressure stimulus, stiffening the gerbil pars flaccida would increase the motion of the pars tensa by 3-10 dB at frequencies below the normal flaccida resonance.

Acoustic Stimulation↗
PubMed1998

The dorsal cochlear nucleus contributes to a high intensity component of the acoustic startle reflex in rats.

The dorsal cochlear nucleus (DCN) has been shown to project to a region of the nucleus reticularis pontis caudalis (PnC) critical for the evocation of startle in rats, suggesting a possible modulatory influence of the DCN on startle. This study examined the involvement of the DCN in the acoustic startle reflex and various other forms of behavioral plasticity seen with this response. Animals received bilateral electrolytic lesions of the DCN and were tested for acoustic startle responses, background noise facilitation, short-term habituation, prepulse inhibition and facilitation, and fear conditioning. Compared to sham lesioned rats, DCN lesioned rats showed a significant reduction in startle amplitude at the two highest startle-eliciting intensities (110 and 115 dB SPL) and normal responses on all other measures. Hence, the DCN appears to contribute to a high intensity component of the acoustic startle response in rats.

Acoustic Stimulation↗
PubMed1999

Acquired resistance to acoustic trauma by sound conditioning is primarily mediated by changes restricted to the cochlea, not by systemic responses.

Hearing loss caused by intense sound exposure can be significantly reduced by pre-exposing subjects to moderate-level acoustic stimuli. This phenomenon occurs in a variety of mammals. We investigated whether sound conditioning provides acquired resistance to acoustic trauma through local mechanisms selectively in the conditioned ears or if systemic mechanisms are involved that would yield contralateral protection in unconditioned ears. Guinea pigs (group I) in which one external ear canal was occluded were exposed to conditioning sound (2-20 kHz, 85 dB SPL, 5 h/day, 10 days). After removing the occlusion, the animals were then subjected bilaterally to intense noise (2-20 kHz, 110 dB SPL, 5 h) 5 days after the last conditioning exposure. Animals without ear canal occlusion were also exposed to the intense sound without conditioning (group II) or following the same conditioning exposure (group III). Intense sound exposure caused significantly greater permanent ABR threshold shifts at all frequencies tested (4, 8, 12, 16 and 20 kHz) in group II than in group III. In group I, the occluded ears showed significantly greater threshold shifts at all frequencies compared to the unoccluded ears. The threshold shifts in the occluded ears in group I were identical to those observed in group II; and the shifts in unoccluded ears in group I were identical to those in group III. Protective effects provided by sound conditioning were almost the same in group III and in the unoccluded ears in group I. The extent of hair cell damage supported the physiological findings. These results indicate that acquired resistance to acoustic trauma provided by sound conditioning is restricted to the cochlea exposed to conditioning sound, suggesting that conditioning protection is mediated primarily by the changes that occur locally within the conditioned cochlea. This animal model, with unilateral external ear canal occlusion during sound conditioning, is useful for studies of the mechanisms of conditioning protection.

Acoustic Stimulation↗
PubMed1999

Prolonged exposure to an augmented acoustic environment ameliorates age-related auditory changes in C57BL/6J and DBA/2J mice.

The effects of exposure to an augmented acoustic environment (AAE) on auditory function were evaluated in mouse strains that exhibit high-frequency hearing loss beginning during young adulthood (the C57BL/6J strain [C57]) or around the time of weaning/ adolescence (the DBA/2J strain [DBA]). Beginning at age 25 days, mice were exposed 12 h every night to a 70 dB SPL broad-band noise AAE. The AAE was maintained until age 14 months in C57 mice and 9 months in DBA mice. Control mice were age-matched and maintained under normal vivarium acoustic conditions. The auditory brainstem response (ABR), acoustic startle response amplitude, and prepulse inhibition (PPI) were used to assess the auditory system. Exposure to the AAE resulted in improved auditory performance in both strains (better PPI, lower ABR thresholds, bigger startle amplitudes).

Acoustic Stimulation↗
PubMed2001

Vestibular evoked myogenic potential (VEMP) in patients with acoustic neuromas.

OBJECTIVE: To study the utility of VEMP (vestibular-evoked myogenic potential) in the diagnosis of acoustic neuromas. METHODS: Eighteen patients with unilateral acoustic neuromas were subjected to this study. Myogenic potential responding to loud click stimuli was recorded at ipsilateral sternocleidomastoid muscle. A normal range of VEMP was obtained from 20 controls. VEMP responses were compared with both, clinical symptoms and results of caloric tests. RESULT: Thirteen out of 18 patients showed decreased responses of VEMP at the affected side. VEMP responses seemed to have little relation with dysequilibrium, spontaneous nystagmus, canal paresis and pure-tone hearing. CONCLUSION: VEMP is useful for detecting dysfunction of inferior vestibular nerve in patients with acoustic neuromas.

Adult↗
PubMed1995

The effect of the sympathetic nervous system upon susceptibility to acoustic trauma.

This study was designed to determine whether the sympathetic nervous system exerts a protective or enhancing effect in acoustic overstimulation. The compound action potential of the cochlea (CAP) was recorded in guinea pigs while the cervical sympathetic nervous system (SNS) was electrically stimulated or after it was surgically eliminated. The stimulation or the elimination of the cervical SNS has no effect on the threshold of CAP. The threshold shift in CAP after acoustic overstimulation (110, 115, or 130 dB SPL for 10 min) was measured in the cervical SNS stimulation group, in the cervical SNS elimination group, and in the control group. When the animal was under insufficient sedation, there was no difference among these three groups. However, the CAP threshold shift was significantly smaller in the cervical SNS stimulation group than in the other two groups when the animals were sufficiently sedated. The cervical SNS stimulation had some protective effect on the susceptibility to acoustic trauma when the systemic SNS activity was suppressed.

Acoustic Stimulation↗
PubMed1986

Acoustic tumor with hearing loss of sudden onset and recovery.

In many cases of acoustic tumor the hearing loss is gradually progressive, but some cases of acoustic tumor show a sudden onset of hearing loss. In this paper we report two interesting cases of acoustic tumors which were diagnosed as sudden deafness at the first examination. Being treated with steroid hormones, their hearing was partially recovered. But the hearing loss recurred in both cases. At the second examination, CT showed the cerebellopontine angle tumors. So it was emphasized that careful questioning as well as the caloric test and the auditory brainstem response (ABR) was important. If one of these tests shows abnormality, the patient should be examined by the CT scan. The same may be said of patients who show recovery due to steroid hormone therapy.

Adult↗
PubMed1987

Acoustic neuroma presenting with sudden and fluctuating hearing loss--a case report.

A case of acoustic neuroma presenting with sudden and fluctuating hearing loss is reported. The patient was a 38-year-old Japanese woman who noticed a sudden onset of hearing loss and tinnitus in the right ear. With a provisional diagnosis of sudden deafness, she was subjected to conservative therapy, including steroid hormone. The hearing started to recover and reached a normal level 2 months after the treatment. Meanwhile, the results of an ABR and plain skull X-rays aroused a suspicion of acoustic neuroma. She was operated on via a middle cranial fossa approach and an acoustic neuroma occupying the internal auditory meatus was removed.

Acute Disease↗
PubMed1998

Correlation between nasal obstruction symptoms and objective parameters of acoustic rhinometry and rhinomanometry.

Acoustic rhinometry and rhinomanometry have been used to assess nasal airway patency objectively. We compared nasal obstruction symptoms before and after decongestion with several parameters of these objective tests. The patients assessed their nasal obstruction using a visual analogue scale (VAS). Cross-sectional areas and nasal resistance were measured by acoustic rhinometry and rhinomanometry before and after topical application of 1% phenylephrine solution in 32 patients with nasal obstruction symptoms. There was no significant correlation between the difference in the VAS and the difference in nasal resistance. There was also no significant correlation between the difference in the VAS and minimal cross-sectional area and cross-sectional areas at 3.3 cm (CA3.3), CA4.0 and CA6.4 from the nosepiece both in the wide and narrow sides and in both nasal cavities before and after nasal decongestion. It is concluded that rhinomanometry and acoustic rhinometry may have no diagnostic value in estimating the severity of nasal obstruction symptoms.

Acoustics↗
PubMed1999

The value of T2(*)-weighted MR images for the diagnosis of acoustic neuromas.

UNLABELLED: The aim of this study was to evaluate high resolution T2(*)-weighted MRI--in our case a 3D CISS sequence--for the diagnosis of acoustic neuromas. Especially to be clarified was if high-resolution T2-weighted sequences can substitute T1-weighted contrast-enhanced sequences, and in which circumstances they can give important additional information when compared with contrast-enhanced T1-weighted sequences. METHODS AND PATIENTS: The MR examinations were performed using a 1.5-Tesla unit with a circularly polarized head coil. All 20 patients (11 females, nine males, aged from 12 to 80 years) with acoustic neuromas underwent preoperative MRI with T2*-weighted 3D CISS (slice thickness, 0.7 mm; acquisition time, 8 min) and pre- and postcontrast T1-weighted 3D MP-RAGE (slice thickness, 0.9 mm; acquisition time, 8 min) sequences. The detectability of acoustic neuromas was evaluated following the consensus of three radiologists using a 3D work station (parameters: tumor presence, extent, nerve attribution). RESULTS: All tumors were detected by both contrast-enhanced 3D MP-RAGE and 3D CISS and the diameters of the lesions were equally well measured. 3D CISS was the best sequence for the attribution of a lesion to a certain nerve. Labyrinthine involvement could be better detected using 3D CISS than contrast-enhanced 3D MP-RAGE. CONCLUSION: High-resolution T2(*)-weighted MRI is a very sensitive method for tumor screening which can also detect even small meatal and labyrinthine neuromas. In the case of abnormal findings (other pathology or variations, e.g. vascular loops); however, contrast-enhanced T1-weighted MRI is necessary in order to confirm the presence of a tumor with typical enhancement.

Adult↗
PubMedDate not supplied

Acoustic rhinometry, rhinomanometry and spirometry of the asthmatics patients with rhinitis symptoms before and after oral corticoid.

INTRODUCTION: Asthma and rhinitis frequently co-exist in the same patient. It may exist a specific condition witch affects the general respiratory activity and also able to produce symptoms into upper and/ or lower airways. PURPOSE: To analyze the alteration and functional burst of upper and lower airways before and after oral corticoid. METHODS: From July of 2000 to August of 2002, sixteen (69 % was female ), acute asthmatics patients with rhinitis symptom assisted in the pneumology department, were analyzed through cross-sectional study using: symptoms questionnaire, physical examination, radiogram, spirometry, acoustic rhinometry, and rhinomanometry. RESULTS: Sixteen patients presented compromising symptoms of the upper airways. In the spirometry, FEV1, FEV1/FVC e FEF25-75%, presented major statistically differences. The acoustic rhinometry presented important statistical differences in the minimal cross- sectional area 1 e 2 in the left side and total nasal volume, after medicine intervention. CONCLUSIONS: The functional evaluations upon lower and upper airways, improvements in FEV1, FEV1/FVC e FEF25-75%, were observed through spirometry and total nasal volume, analyzing the acoustic rhinometry after oral corticoid.

Adolescent↗
PubMedDate not supplied

The effects of perinatal AZT exposure on the acoustic startle response in adult rats.

AZT (azidothymidine, zidovudine, ZDV) has become the standard medication to prevent the transmission of the human immunodeficiency virus from mother to fetus. The present study was designed to assess the acoustic startle response (ASR) in adult rats that had been perinatally exposed to AZT. Each litter was randomly assigned to a treatment group: nontreated, AZT 0, 50, 100 or 150 mg/kg. Once daily gastric intubation began prenatally between gestational day (G) 19 and 22 and then continued postnatally between postnatal day (PND) 2 and 20. Between PND75 and PND80, animals were tested for habituation to the acoustic stimuli and prepulse inhibition following a challenge of either saline or 1.0 mg/kg amphetamine (AMP) intraperitoneally. Amphetamine increased ASR and startle latencies throughout the session. The AZT100 dose increased ASR habituation. AZT treatment did not affect prepulse inhibition. Females treated with AZT150 continued to show high ASRs at the end of the startle session. AZT-treated animals showed a dose-dependent increase in peak latency, suggesting a possible abnormal conduction velocity. These effects are independent of handling and intubation effects. Therefore, perinatal AZT treatment results in long-term changes within the primary acoustic startle pathway.

Acoustic Stimulation↗
PubMed2000

Vocal violence in actors: an investigation into its acoustic consequences and the effects of hygienic laryngeal release training.

Acoustic analysis techniques were used to investigate the short-term consequences of vocally violent behavior, and to compare voice production before and after training in hygienic laryngeal release (HLR) techniques. Twenty-seven actors ranging in age from 17 to 48 years were audiorecorded before and after multiple productions of 4 vocally violent behaviors: grunting, groaning, sobbing, and shouting. After training in HLR techniques, the experimental protocol was repeated. Audiorecordings of vowels (produced at 3 pitch levels: modal F0, minimum F0, maximum F0) before and after vocal violence, and before and after HLR training, were analyzed using the Multidimensional Voice Program (4305, Kay Elemetrics Corp, Lincoln Park, NJ). After vocal violence, no consistent acoustic changes were detected for voice generated at modal and minimum F0; however, significant increases in both fundamental frequency range and maximum F0 were observed. After training in HLR techniques, acoustic measures sensitive to pitch and amplitude perturbation, and non-harmonic noise, improved across pitch levels. The results also indicated that vocal training does defend the laryngeal system from undesirable changes related to vocally violent maneuvers that might surface at the extremes of an actor's pitch range. Because the HLR technique used in this investigation was multimodal, interesting questions are raised regarding which aspect of training is primarily responsible for the observed effects. Further study is required to identify such factors.

Adolescent↗
PubMed2000

Perceptual and acoustic study of professionally trained versus untrained voices.

Acoustic and perceptual analyses were completed to determine the effect of vocal training on professional singers when speaking and singing. Twenty professional singers and 20 nonsingers, acting as the control, were recorded while sustaining a vowel, reading a modified Rainbow Passage, and singing "America the Beautiful." Acoustic measures included fundamental frequency, duration, percent jitter, percent shimmer, noise-to-harmonic ratio, and determination of the presence or absence of both vibrato and the singer's formant. Results indicated that, whereas certain acoustic parameters differentiated singers from nonsingers within sex, no consistently significant trends were found across males and females for either speaking or singing. The most consistent differences were the presence or absence of the singer's vibrato and formant in the singers versus the nonsingers, respectively. Perceptual analysis indicated that singers could be correctly identified with greater frequency than by chance alone from their singing, but not their speaking utterances.

Adult↗
PubMed2001

Acoustic analyses of trained singers perceptually identified from speaking samples.

This study investigated selected acoustic cues in the speaking voices of five professional singers; cues that may have enabled naïve listeners to differentiate them from nonsingers and other trained singers who were not consistently identified from their speaking voices. Subjects were divided into three groups based on listeners' perceptual judgments. Group I, the identified singers, consisted of five professional singers, three males and two females, with an average identification score, from their speaking utterances, of 79%. Group II, the unidentified singers, consisted of 15 trained singers, seven males and eight females, who, as a group, were identified correctly from their speaking utterances only 52% of the time. Group III consisted of 20 nonsingers who were incorrectly identified from their speaking utterances as singers only 36% of the time, that is, they were correctly identified as nonsingers from their speech 64% of the time. Acoustic parameters chosen for measurement from vowel productions were: (1) percent jitter, (2) percent shimmer, and (3) noise-to-harmonic ratio. The second sentence of the "Rainbow Passage" was selected to compare several frequency and duration measures between the three groups. These were: (1) mean speaking fundamental frequency, (2) standard deviation of the fundamental frequency, (3) sentence duration, (4) word duration, and (5) consonant/vowel ratio. The data indicated that the acoustic parameters that most consistently distinguished the identified singers from the unidentified singers and the nonsingers were fundamental frequency variation and durational differences. The identified singers varied their speaking fundamental frequency significantly more than did both the unidentified singers and the nonsingers. The identified singers also had longer vocalic segments than did the others.

Adult↗
PubMed2001

Laryngostroboscopic, acoustic, and environmental characteristics of high-risk vocal performers.

Vocal performance often requires excessively high vocal demand. In particular "high-risk" performers, a group of individuals who use their voices at their maximum effort level, are often exposed to unique vocal abuse characteristics which include high environmental and performance demands and inconsistencies of cast performance. Three categories of high-risk performers were studied: musical theater, choral ensemble, and street theater. Musical theater performers produce a Broadway, West End "belting" style voice. Street theater performers use a high-energy pitch varying dialogue in order to imitate a desired character voice. Choral ensemble performance requires group cohesion and blending of four-part harmony. The melodies require sustained vocal durations within each of the respective registers. For each of these studied groups vocal tasks of sustained production of /i/ and /a/ were subjected to analysis. Acoustic measures included fundamental frequency, standard deviation of fundamental frequency, jitter percent, shimmer percent, and noise-to-harmonic ratio. Laryngostroboscopic parameters were assessed during sustained /i/. Environmental acoustic sound field measurements were made using an A weighting and linear weighting sound pressure level. These weightings were used to describe noise levels and vocal output, respectively, within the performance environments. Results of the analysis suggest that high-risk performers are a unique performance type defined by distinctive, acoustic, laryngostroboscopic, and environmental characteristics.

Adolescent↗
PubMed1996

Subjective, laryngoscopic, and acoustic measurements of laryngeal reflux before and after treatment with omeprazole.

Laryngeal manifestation of gastroesophageal reflux is felt to be prevalent in our society. In general, diagnosis has been based primarily on symptoms. Historically, additional testing included laryngoscopy, barium swallow, manometry, and more recently, single- and double-probe pH monitoring. We evaluated 68 patients who were symptomatically suggestive of having reflux laryngitis. We administered surveys grading their symptoms. All patients underwent standardized videolaryngostroboscopic evaluation and computerized acoustic analysis. Patients then underwent a uniform therapy of dietary restrictions and omeprazole, a hydrogen ion inhibitor, for 12 weeks. Patients were then retested. This regimen demonstrated an 85% success of relieving symptoms. Utilizing the new laryngoscopic grading system, improvement was found to be statistically significant in improvement of all findings except granulomas. In patients with the pretherapy complaint of hoarseness, acoustic measures of jitter, shimmer, habitual frequency, and frequency range all showed significant improvement. The authors conclude that in patients with symptomatic reflux laryngitis, standardized videolaryngoscopy and, if hoarse, acoustic analysis are useful exam techniques to aide diagnosis and monitor therapy. Anti-reflux therapy with omeprazole is effective and improvement can be objectively demonstrated with the techniques described.

Adult↗
PubMed1997

Gender presentation: perceptual and acoustical analyses of voice.

This study investigated the perceptual and acoustical characteristics of vocal presentation in both the masculine and the feminine modes by the same group of male subjects. Listeners (N = 88) evaluated 22 voice samples by using 18 semantic differential scales and 57 adjectives. The 22 voice samples were provided by 11 biologically male speakers, who described themselves as heterosexual crossdressers. Each speaker read a standard passage under controlled conditions. In one reading, they demonstrated their typical masculine voice and in the other they spoke in their feminine voice. Acoustical analyses included mean fundamental frequency, frequency range, overall passage duration, and duration of a sample of stressed vowels. Results indicated that listeners heard significant differences between masculine and feminine presentations across the 11 speakers and the 18 semantic differential scales. Masculine-feminine and high-low pitch were the most salient scales in the perceptual judgments. Acoustical analyses indicated wide variation according to speaker and condition. Clinical applications are provided.

Adult↗