Hearing in Mice via GSR Audiometry

1963 ◽  
Vol 6 (4) ◽  
pp. 359-368 ◽  
Author(s):  
Charles I. Berlin
Keyword(s):  
Inverse Relationship ◽  
Sound Pressure ◽  
Single Units ◽  
Sensitivity Curve ◽  
Basic Tool ◽  
Eighth Nerve ◽  
Pure Tones ◽  
Conditioned Responses ◽  
Frequency Intensity ◽  
Near Threshold

Hearing in mice has been difficult to measure behaviorally. With GSR as the basic tool, the sensitivity curve to pure tones in mice has been successfully outlined. The most sensitive frequency-intensity combination was 15 000 cps at 0-5 dB re: 0.0002 dyne/cm 2 , with responses noted from 1 000 to beyond 70 000 cps. Some problems of reliability of conditioning were encountered, as well as findings concerning the inverse relationship between the size of GSR to unattenuated tones and the sound pressure necessary to elicit conditioned responses at or near threshold. These data agree well with the sensitivity of single units of the eighth nerve of the mouse.

Phase-Locked Responses to Pure Tones in the Inferior Colliculus

2006 ◽  
Vol 95 (3) ◽  
pp. 1926-1935 ◽  
Author(s):  
Liang-Fa Liu ◽  
Alan R. Palmer ◽  
Mark N. Wallace
Keyword(s):  
Guinea Pig ◽  
Inferior Colliculus ◽  
Phase Locking ◽  
Single Units ◽  
Central Nucleus ◽  
Dorsal Cortex ◽  
Upper Limits ◽  
Ascending Pathways ◽  
Pure Tones ◽  
The Brain

In the auditory system, some ascending pathways preserve the precise timing information present in a temporal code of frequency. This can be measured by studying responses that are phase-locked to the stimulus waveform. At each stage along a pathway, there is a reduction in the upper frequency limit of the phase-locking and an increase in the steady-state latency. In the guinea pig, phase-locked responses to pure tones have been described at various levels from auditory nerve to neocortex but not in the inferior colliculus (IC). Therefore we made recordings from 161 single units in guinea pig IC. Of these single units, 68% (110/161) showed phase-locked responses. Cells that phase-locked were mainly located in the central nucleus but also occurred in the dorsal cortex and external nucleus. The upper limiting frequency of phase-locking varied greatly between units (80−1,034 Hz) and between anatomical divisions. The upper limits in the three divisions were central nucleus, >1,000 Hz; dorsal cortex, 700 Hz; external nucleus, 320 Hz. The mean latencies also varied and were central nucleus, 8.2 ± 2.8 (SD) ms; dorsal cortex, 17.2 ms; external nucleus, 13.3 ms. We conclude that many cells in the central nucleus receive direct inputs from the brain stem, whereas cells in the external and dorsal divisions receive input from other structures that may include the forebrain.

Annoyance of Low Frequency Tones and Objective Evaluation Methods

2005 ◽  
Vol 24 (2) ◽  
pp. 81-95 ◽  
Author(s):  
Jishnu K. Subedi ◽  
Hiroki Yamaguchi ◽  
Yasunao Matsumoto ◽  
Mitsutaka Ishihara
Keyword(s):  
Sound Pressure ◽  
Hearing Threshold ◽  
Low Frequency ◽  
Objective Evaluation ◽  
Evaluation Methods ◽  
Frequency Separation ◽  
Rate Of Increase ◽  
Pure Tones ◽  
Four Levels ◽  
Loudness Model

Annoyance of low frequency pure and combined tones was measured in a laboratory experiment. Three low frequency tones at frequencies of 31.5, 50 and 80 Hz at four sound pressure levels, from about 6 dB to 24 dB above average hearing threshold, were selected as pure tones. The combined tones were combinations of two tones: the four levels of 31.5, 50 and 80 Hz tones and a constant level 40 Hz tone. The results showed that the rate of increase in annoyance of pure tones with increase in the sound pressure level was higher at lower frequencies, as reported in previous studies. The results for the combined tones showed that the increase in the annoyance of the combined tone compared to the annoyance of pure tone was dependent on the level difference of the two tones and their frequency separation. These results were compared with the evaluation obtained from different objective methods. The three methods were Moore's loudness model, the low frequency A-weighting and the total energy summation used as objective evaluation methods. Among the methods, the low frequency A-weighting gave the best correlation.

Preferences for Single Tone Stimuli

1974 ◽  
Vol 22 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Steven K. Hedden
Keyword(s):  
Analysis Of Variance ◽  
Factorial Analysis ◽  
Wave Form ◽  
Music Majors ◽  
Single Tone ◽  
Main Effect ◽  
Pure Tones ◽  
Nonmusic Majors ◽  
Tonal Stimuli ◽  
Frequency Intensity

This research used a factorial analysis of variance to examine preferences for tonal stimuli that differed in frequency, intensity, or wave form. For the sample of music majors, wave form appeared to have the greatest effect on preferences; pure tones were most preferred. The main effect for intensity also was significant, as was the interaction of intensity and wave form. For the sample of nonmusic majors, the predominant influence on preferences seemed to be intensity. The nonmusic majors preferred the softer of the two levels. In addition, the main effect for wave form was significant, as were the interactions of wave form with intensity and frequency with intensity.

Comparison of Seven Systems for High-Frequency Air-Conduction Audiometry

1970 ◽  
Vol 13 (2) ◽  
pp. 254-270 ◽  
Author(s):  
Cecil K. Myers ◽  
J. Donald Harris
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Frequency Noise ◽  
Noise Band ◽  
Frequency Range ◽  
Pure Tones ◽  
Auditory Acuity ◽  
Narrow Bands ◽  
Reference Threshold ◽  
Air Conduction

Seven equipment systems were assembled to examine human auditory acuity from 8 to 20 kHz. Two loudspeakers and two earphones were examined, together with two types of stimulus (pure tones and narrow bands of noise) and two psychometric methods (Limits and Adjustments). All systems were capable of providing usably reliable thresholds on 28 ears throughout the whole frequency range. When carefully calibrated, several systems (those involving loudspeakers, as well as those involving earphones) yielded comparable reference threshold sound-pressure levels at the eardrum. A preference was expressed for a system using Bekesy threshold tracking with a changing-frequency noise band of 300 Hz, and for a discrete-tone system using the Method of Constants.

Topography of intensity tuning in cat primary auditory cortex: single-neuron versus multiple-neuron recordings

1995 ◽  
Vol 73 (1) ◽  
pp. 190-204 ◽  
Author(s):  
M. L. Sutter ◽  
C. E. Schreiner
Keyword(s):  
Single Neuron ◽  
Primary Auditory Cortex ◽  
Single Units ◽  
Pool Data ◽  
Single Neurons ◽  
Firing Rates ◽  
A Cell ◽  
Multiple Unit ◽  
Pure Tones ◽  
Multiple Units

1. We studied the spatial distributions of amplitude tuning (monotonicity of rate-level functions) and response threshold of single neurons along the dorsoventral extent of cat primary auditory cortex (AI). To pool data across animals, we used the multiple-unit map of monotonicity as a frame of reference. Amplitude selectivity of multiple units is known to vary systematically along isofrequency contours, which run roughly in the dorsoventral direction. Clusters sharply tuned for intensity (i.e., "nonmonotonic" clusters) are located near the center of the contour. A second nonmonotonic region can be found several millimeters dorsal to the center. We used the locations of these two nonmonotonic regions as reference points to normalize data across animals. Additionally, to compare this study to sharpness of frequency tuning results, we also used multiple-unit bandwidth (BW) maps as references to pool data. 2. The multiple-unit amplitude-related topographies recorded in previous studies were confirmed. Pooled multiple-unit maps closely approximated the previously reported individual case maps when the multiple-unit monotonicity or the map of bandwidth (in octaves) of pure tones to which a cell responds 40 dB above minimum threshold were used as the pooling reference. When the map of bandwidth (in octaves) of pure tones to which a cell responds 10 dB above minimum threshold map was used as part of the measure, the pooled spatial pattern of multiple-unit activity was degraded. 3. Single neurons exhibited nonmonotonic rate-level functions more frequently than multiple units. Although common in single-neuron recordings (28%), strongly nonmonotonic recordings (firing rates reduced by > 50% at high intensities) were uncommon (8%) in multiple-unit recordings. Intermediately nonmonotonic neurons (firing rates reduced between 20% and 50% at high intensities) occurred with nearly equal probability in single-neuron (28%) and multiple-unit (26%) recordings. The remaining recordings for multiple units (66%) and single units (44%) were monotonic (firing rates within 20% of the maximum at the highest tested intensity). 4. In ventral AI (AIv), the topography of monotonicity for single units was qualitatively similar to multiple units, although single units were on average more intensity selective. In dorsal AI (AId) we consistently found a spatial gradient for sharpness of intensity tuning for multiple units; however, for pooled single units in Aid there was no clear topographic gradient. 5. Response (intensity) thresholds of single neurons were not uniformly distributed across the dorsoventral extent of AI.(ABSTRACT TRUNCATED AT 400 WORDS)

Middle Ear Implantable Hearing Device: Ongoing Animal and Human Evaluation

1988 ◽  
Vol 97 (6) ◽  
pp. 650-658 ◽  
Author(s):  
Jack Hough ◽  
Kenneth J. Dormer ◽  
Mary Meikle ◽  
R. Stan Baker ◽  
Tom Himelick
Keyword(s):  
Middle Ear ◽  
Sound Pressure ◽  
High Fidelity ◽  
Speech Discrimination ◽  
Human Evaluation ◽  
Final Design ◽  
Hearing Device ◽  
Pure Tones ◽  
Time Of Operation ◽  
Sound Processor

The first five patients have been permanently implanted with an electromagnetic middle ear implantable hearing device. Hearing tests were performed at the time of operation and at 8 weeks postoperatively with a coil held at the isthmus of the ear canal. All patients reported clear, high fidelity sound, as proven by speech discrimination scores. Improvements were seen in all frequencies, including 4,000 Hz. Improvement in pure tones as tested with an audiometer monitoring sounds amplified by a 3-V sound processor was as high as 50 dB sound pressure level. That which remains to be done is the final design of a compact, wearable sound processor with filtering and signal-processing capabilities to meet the needs of the sensorineural hearing-impaired population.

The Occlusion Effect and Ear Canal Sound Pressure Level

1998 ◽  
Vol 7 (2) ◽  
pp. 50-54 ◽  
Author(s):  
Marc A. Fagelson ◽  
Frederick N. Martin
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Bone Conduction ◽  
Frontal Bone ◽  
Pressure Level ◽  
Mastoid Process ◽  
Ear Canal ◽  
External Canal ◽  
Pure Tones ◽  
Occlusion Effect

Comparisons were made between changes in the audibility of bone-conduction stimuli to differences in the sound pressure present in the external auditory canal when ears were occluded. Fifteen listeners with normal middle ear function were tested using pure tones of 250, 500, and 1000 Hz, delivered via a bone-conduction oscillator placed on the mastoid process and the frontal bone. At all three frequencies, and both sites of stimulation, ear canal sound pressures were greater in the occluded than in the unoccluded conditions. Concurrently, the test signals were detected at lower intensities, although the changes in audibility and external canal sound pressure levels were not unity. The occlusion effect was attenuated slightly when the skull was vibrated from the frontal bone.

Aural Acoustic-Immittance Measurements

1981 ◽  
Vol 46 (4) ◽  
pp. 413-421 ◽  
Author(s):  
Richard H. Wilson ◽  
Janet E. Shanks ◽  
Therese M. Velde
Keyword(s):  
Sound Pressure ◽  
Broadband Noise ◽  
Intensity Level ◽  
Growth Data ◽  
Acoustic Reflex ◽  
Individual Subject ◽  
Acoustic Admittance ◽  
Sound Pressure Levels ◽  
Pure Tones ◽  
The Individual

Bilateral measurements of the aural acoustic-immittance characteristics of the middle-ear transmission systems of 48 subjects were made with an acoustic-admittance meter. The measurements, including static acoustic-immittance, acoustic-reflex thresholds, and acoustic-reflex growth functions, were made using a 220-Hz probe. The contralateral reflex data for three pure tones (500, 1000, and 2000 Hz) and for broadband noise were acquired in 2-dB steps at sound-pressure levels from 84–116 dB (tones) and 66–116 dB (noise) during ascending- and descending-intensity level runs. For all acoustic-immittance measurements, right ear and left ear comparisons were made and found not to be significantly different. The individual subject data then were expressed as the absolute differences between ears. In this manner normative inter-aural immittance differences were defined. The peak static immittance data were analyzed in terms of median inter-aural differences and upper 80% cut-off values. The 80% range for normal immittance values were smaller for a within subject versus an across subject comparison. For acoustic-reflex thresholds, a disparity between ears of >10 dB was suggested as indicative of an abnormality in the auditory mechanism. Finally, the reflex-growth data indicated mean inter-aural absolute differences that ranged to .040–.043 acoustic mmhos (300–400 acoustic ohms) at the higher reflex activator sound-pressure levels.

The Use of Sound Level Meter Apps in the Clinical Setting

2016 ◽  
Vol 25 (1) ◽  
pp. 14-28 ◽  
Author(s):  
Gaetano Fava ◽  
Gisele Oliveira ◽  
Melody Baglione ◽  
Michael Pimpinella ◽  
Jaclyn B. Spitzer
Keyword(s):  
Clinical Setting ◽  
Sound Pressure ◽  
Sound Level ◽  
Healthy Adults ◽  
Anechoic Chamber ◽  
Fort Worth ◽  
Sound Level Meter ◽  
Pure Tones ◽  
Level Meter

PurposeThe purpose of this study was to compare sound level meter (SLM) readings obtained using a Larson-Davis (Depew, NY) Model 831 Type 1 SLM, a RadioShack (Fort Worth, TX) SLM, and iPhone 5 (Apple, Cupertino, CA) SLM apps.MethodIn Procedure 1, pure tones were measured in an anechoic chamber (125, 250, 500, 1000, 2000, 4000, and 8000 Hz); sound pressure levels (SPLs) ranged from 60 to 100 dB SPL in 10-dB increments. In Procedure 2, human voices were measured. Participants were 20 vocally healthy adults (7 women, 13 men; mean age = 25.1 years). The task was to sustain a vowel “ah” at 3 intensity levels: soft, habitual, and loud. Microphones were lined up equal distances from the participant's mouth, and recordings were captured simultaneously.ResultsOverall, the 3 SLM apps and the RadioShack SLM yielded inconsistent readings compared with the Type 1 SLM.ConclusionThe use of apps for SPL readings in the clinical setting is premature because all 3 apps adopted were incomparable with the Type 1 SLM.

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