scholarly journals Acoustic reflexes of middle‐ear and laryngeal muscles in the FM bat Myotis lucifugus

1976 ◽  
Vol 60 (S1) ◽  
pp. S4-S4 ◽  
Author(s):  
Philip ◽  
H.‐S. Jen ◽  
Joachim Ostwald ◽  
Nobuo Suga
Keyword(s):  
Middle Ear ◽  
Myotis Lucifugus ◽  
Laryngeal Muscles ◽  
Acoustic Reflexes ◽  
Fm Bat

Coding of directional information by single neurones in the S-segment of the FM bat, Myotis lucifugus

1980 ◽  
Vol 87 (1) ◽  
pp. 203-216
Author(s):  
P. H. Jen
Keyword(s):  
Single Unit ◽  
Median Plane ◽  
Myotis Lucifugus ◽  
Directional Information ◽  
Stimulus Pulse ◽  
Fm Bat ◽  
Single Neurones ◽  
The Relationship ◽  
Correct Level ◽  
Stimulus Direction

1. Response parameters of S-segment neurones of the FM bat Myotis lucifugus were measured as a sound was delivered from different azimuthal angles around the animal's head. 2. The response parameters investigated were the amplitude and threshold of the evoked potential (N3) of the S-segment, together with the threshold, latency and number of impulses (per stimulus pulse) of single units. 3. All the neurones studied had their lowest thresholds either at 20-40 degrees contralateral, or 20-40 degrees ipsilateral or at the front (0 degrees). 4. The amplitude of the sound affected the relationship between stimulus direction and the amplitude of a non-monotonic N3, and the relationship between stimulus direction and the number of impulses of a non-monotonic single unit. It had so such effects with a monotonic N3 and a monotonic single unit. 5. From a study of N3 amplitudes and numbers of impulses of single neurones, it appeared that an azimuthal difference as small as 3 degrees could be easily coded at a 95% correct level with stimuli presented at around 20 degrees ipsilateral, 20 degrees contralateral, and at the front. 6. The inter-aural pressure difference (IPD), which is considered an essential cue for echolocation in Myotis (Shimozawa et al. 1974), changed linearly with angle from 0 to 40 degrees lateral at a rate of 0.4 dB/degree for sounds between 33.5 and 49.0 kHz. 7. Assuming the just-detectable IPD to be 0.5 dB (as in man), the minimum detectable azimuthal difference of Myotis around the median plane would be 1.25 degrees.

Phasor Admittance Measurements of the Middle Ear II.Normal Phasor Tympanograms and Acoustic Reflexes

1984 ◽  
Vol 13 (4) ◽  
pp. 265-274 ◽  
Author(s):  
M. E. Lutman ◽  
H. McKenzie ◽  
I. R. C. Swan
Keyword(s):  
Middle Ear ◽  
Acoustic Reflexes

Peripheral control of acoustic signals in the auditory system of echolocating bats

1975 ◽  
Vol 62 (2) ◽  
pp. 277-311 ◽  
Author(s):  
N. Suga ◽  
P. H. Jen
Keyword(s):  
Auditory System ◽  
Middle Ear ◽  
Lateral Line ◽  
Acoustic Signals ◽  
Myotis Lucifugus ◽  
The Self ◽  
Cochlear Microphonic ◽  
Fusion Frequency ◽  
Incoming Signal ◽  
Self Stimulation

Many species of echolocating bats emit intense orientation sounds. If such intense sounds directly stimulated their ears, detection of faint echoes would be impaired. Therefore, possible mechanisms for the attenuation of self-stimulation were studied with Myotis lucifugus. The acoustic middle-ear-muscle reflex could perfectly and transiently regulate the amplitude of an incoming signal only at its beginning. However, its shortest latency in terms of electromyograms and of the attenuation of the cochlear microphonic was 3–4 and 4–8 msec, respectively, so that these muscles failed to attenuate orientation signals by the reflex. The muscles, however, received a message from the vocalization system when the bat vocalized, and contracted synchronously with vocalization. The duration of the contraction-relaxation was so short that the self-stimulation was attenuated, but the echoes were not. The tetanus-fusion frequency of tha stapedium muscle ranged between 260 and 320/sec. Unlike the efferent fibres in the lateral-line and vestibular systems, the olivo-cochlear bundle showed no sign of attenuation of self-stimulation.

scholarly journals Acoustic reflexes are common but not pervasive: evidence using a diagnostic middle ear analyser

2017 ◽  
Vol 57 (sup1) ◽  
pp. S42-S50 ◽  
Author(s):  
Kara D. McGregor ◽  
Gregory A. Flamme ◽  
Stephen M. Tasko ◽  
Kristy K. Deiters ◽  
William A. Ahroon ◽  
...  
Keyword(s):  
Middle Ear ◽  
Acoustic Reflexes

Coordinated activities of middle-ear and laryngeal muscles in echolocating bats

Science ◽  
1976 ◽  
Vol 191 (4230) ◽  
pp. 950-952 ◽  
Author(s):  
P. Jen ◽  
N Suga
Keyword(s):  
Middle Ear ◽  
Laryngeal Muscles

scholarly journals Clinical Investigation and Mechanism of Air-Bone Gaps in Large Vestibular Aqueduct Syndrome

2007 ◽  
Vol 116 (7) ◽  
pp. 532-541 ◽  
Author(s):  
Saumil N. Merchant ◽  
Hideko H. Nakajima ◽  
Christopher Halpin ◽  
Joseph B. Nadol ◽  
Daniel J. Lee ◽  
...  
Keyword(s):  
Inner Ear ◽  
Middle Ear ◽  
Bone Conduction ◽  
Distortion Product Otoacoustic Emission ◽  
Low Frequencies ◽  
Distortion Product ◽  
Vestibular Aqueduct ◽  
Acoustic Reflexes ◽  
Large Vestibular Aqueduct Syndrome ◽  
Large Vestibular Aqueduct

Objectives: Patients with large vestibular aqueduct syndrome (LVAS) often demonstrate an air-bone gap at the low frequencies on audiometric testing. The mechanism causing such a gap has not been well elucidated. We investigated middle ear sound transmission in patients with LVAS, and present a hypothesis to explain the air-bone gap. Methods: Observations were made on 8 ears from 5 individuals with LVAS. The diagnosis of LVAS was made by computed tomography in all cases. Investigations included standard audiometry and measurements of umbo velocity by laser Doppler vibrometry (LDV) in all cases, as well as tympanometry, acoustic reflex testing, vestibular evoked myogenic potential (VEMP) testing, distortion product otoacoustic emission (DPOAE) testing, and middle ear exploration in some ears. Results: One ear with LVAS had anacusis. The other 7 ears demonstrated air-bone gaps at the low frequencies, with mean gaps of 51 dB at 250 Hz, 31 dB at 500 Hz, and 12 dB at 1,000 Hz. In these 7 ears with air-bone gaps, LDV showed the umbo velocity to be normal or high normal in all 7; tympanometry was normal in all 6 ears tested; acoustic reflexes were present in 3 of the 4 ears tested; VEMP responses were present in all 3 ears tested; DPOAEs were present in 1 of the 2 ears tested, and exploratory tympanotomy in 1 case showed a normal middle ear. The above data suggest that an air-bone gap in LVAS is not due to disease in the middle ear. The data are consistent with the hypothesis that a large vestibular aqueduct introduces a third mobile window into the inner ear, which can produce an air-bone gap by 1) shunting air-conducted sound away from the cochlea, thus elevating air conduction thresholds, and 2) increasing the difference in impedance between the scala vestibuli side and the scala tympani side of the cochlear partition during bone conduction testing, thus improving thresholds for bone-conducted sound. Conclusions: We conclude that LVAS can present with an air-bone gap that can mimic middle ear disease. Diagnostic testing using acoustic reflexes, VEMPs, DPOAEs, and LDV can help to identify a non?middle ear source for such a gap, thereby avoiding negative middle ear exploration. A large vestibular aqueduct may act as a third mobile window in the inner ear, resulting in an air-bone gap at low frequencies.

scholarly journals Coordinated activity of the middle‐ear and laryngeal muscles in echolocating bats

1975 ◽  
Vol 57 (S1) ◽  
pp. S42-S42 ◽  
Author(s):  
P. H.‐S. Jen ◽  
H. Alster ◽  
N. Suga
Keyword(s):  
Middle Ear ◽  
Laryngeal Muscles

Tympanometry Screening Criteria in Children Ages 5–7 Yr

2014 ◽  
Vol 25 (10) ◽  
pp. 927-936 ◽  
Author(s):  
De Wet Swanepoel ◽  
Robert H. Eikelboom ◽  
Robert H. Margolis
Keyword(s):  
Cohort Study ◽  
Middle Ear ◽  
Peak Pressure ◽  
Large Population ◽  
Screening Method ◽  
Referral Rates ◽  
Screening Programs ◽  
Referral Criteria ◽  
Acoustic Reflexes ◽  
The Impact

Background: Despite its value as a diagnostic measure of middle-ear function, recommendations for tympanometry as a screening test for middle-ear disorders have been tentative. This is primarily due to concerns related to over-referrals, cost-effectiveness, variability in referral criteria and protocols, variable reported screen performance, and influence of demographic and environmental factors. Purpose: The current study assessed tympanometry in a large population of children between 5–7 yr old in terms of normative ranges, performance of current recommended referral criteria, and associations with independent demographic and environmental variables. Research Design: Retrospective cohort study. Study Sample: A total of 2868 children and their families were originally enrolled in the Raine Cohort Study in Western Australia. Of these, 1469 children between 5–7 yr old (average age = 5.97 yr, SD = 0.17 yr) were evaluated with tympanometry and pure-tone audiometry screening. Data Collection and Analysis: Tympanometry was conducted using a 226 Hz probe tone with screening ipsilateral acoustic reflexes recorded using a 1000 Hz stimulus. Hearing screening was conducted using pure tones at 20 dB HL for 1000, 2000, and 4000 Hz. Relationships among normative ranges (90% and 95% ranges) for tympanometric indices, age, gender, and month of test were determined. Associations were also explored between tympanometry referrals and month of test, gender, and absence of acoustic reflexes. Results: Normative 90% ranges for tympanometric peak pressure was –275 to 15 daPa, 60–150 daPa for peak compensated tympanometric width, 0.2 and 1.0 mmho for peak compensated static admittance, and 0.7–1.3 cm3 for ear canal volume. Current screening guidelines result in high referral rates for children 5–7 yr old (13.3% and 11.5% using the American Speech-Language-Hearing Association [ASHA] and American Academy of Audiology [AAA] guidelines, respectively). The subgroup of children 6–7 yr old had referral rates (for ears tested) of only 3.3% and 2.7%, respectively, according to ASHA and AAA guidelines. The prevalence of middle-ear effusion (admittance <0.1 mmho) was significantly different across seasons, with the highest (13.5%) in September and lowest (3.8%) in January. Month of test was associated with a general decrease in tympanometric peak pressure across the population. Conclusions: An 80% reduction in tympanometry referrals for children ages 6 and 7 yr compared with children age 5 yr argues for tympanometry as a first-tier screening method in older children only. The impact of regional seasonal influences, representing an increase in referrals as high as 3.5 times from one month to another, should also inform and direct pediatric screening programs for middle-ear functioning and/or hearing loss.

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