kHz Pure Tone Research Articles

Auditory masking of tonal and conspecific signals by continuous active sonar, amplitude modulated noise, and Gaussian noise in killer whales (Orcinus orca).

Continuous active sonar is thought to mitigate severe acoustic impacts due to its lower sound pressure level compared to pulsed active sonar typically used by world navies. However, due to its almost continuous duty cycle, continuous active sonar could have a higher potential for auditory masking. Here, we evaluate the auditory masking potential of several noise types including a recording of continuous active sonar, amplitude modulated noise, and Gaussian noise, on signal detection in two killer whales. Signals were either a 1.5 kHz pure tone or a recording of a broadband burst-pulse killer whale call. For the 1.5 kHz tone, all noise types resulted in statistically significant masking, however, there was a release from masking of approximately 13 dB for the amplitude-modulated noise. When the killer whale call was the signal, the whales employed an off-frequency listening strategy where the whales were able to detect frequency components of the signal that did not directly overlap with the noise. However, this strategy was less useful for the continuous active sonar noise due to its broadband harmonic structure. Continuous active sonar has spectral features that considerably overlap with those of killer whale calls, making this type of noise an effective auditory masker.

Analysis of the efficacy of fiber laser stapes fenestration in the treatment of 58 cases of otosclerosis and ossicular malformation

Objective: To explore the surgical efficacy of conductive deafness caused by otosclerosis and ossicular malformation with 980 nm fiber laser stapedial floor fenestration. Methods: Data of 58 patients (ears) who were diagnosed with conductive deafness caused by otosclerosis (49 ears) and ossicular malformation (9 ears) treated by 980 nm Diode laser small-fenestra stapedotomy were retrospectively analyzed. Air conduction (AC) thresholds, bone conduction (BC) thresholds, and air-bone gap (ABG) at 0.5, 1, 2, 4 kHz pure tone frequencies were compared before and 3 months after surgery, and the advantages and precautions of 980 nm fiber laser were summarized. Paired t-test (SPSS 26.0 software) was use to analyze the listening data. Results: Fiber optic laser stapes fenestration and artificial stapes implantation were successfully completed in all 57 cases (ears), the hearing of another one patient (ear) with floating malformation of detachment of stapedial floor was lower than that before surgery. Preoperative at 0.5, 1, 2, 4 kHz frequencies of AC thresholds, BC thresholds, and ABG were (65.4±9.7) dB, (27.2±8.9) dB, and (38.2±9.8) dB respectively. Postoperative 3 months at the same frequency of AC thresholds, BC thresholds, and ABG were (42.1±11.3) dB, (26.9±6.6) dB, and (15.2±9.1) dB. Preoperative and postoperative of AC threshold and ABG were statistically significant at 0.5, 1, 2, 4 kHz (t value was 13.270 and13.948, both P<0.01), and yet the BC threshold was not statistically significant before and after surgery at the same frequency (t=0.418, P>0.05). Conclusions: 980 nm fiber laser stapes floor fenestration is an effective treatment for conductive deafness caused by otosclerosis and ossicular malformation.

Listening handicap in tinnitus patients with normal extended high frequencies from the perspective of the autonomic nervous system–Effort or fatigue?

ObjectiveIn previous studies, the results regarding the presence of listening effort or fatigue in tinnitus patients were inconsistent. The reason for this inconsistency could be that extended high frequencies, which can cause listening handicap, were not within normal limits. Therefore, this study aimed to evaluate the listening skills in tinnitus patients by matching the normal hearing thresholds at all frequencies, including the extended high frequency. MethodsEighteen chronic tinnitus patients and thirty matched healthy controls having normal pure-tone average with symmetrical hearing thresholds was included. Subjects were evaluated with 0.125–20 kHz pure-tone audiometry, Montreal cognitive assessment test (MoCA), Tinnitus Handicap Inventory (THI), Matrix Test, Pupillometry. ResultsPupil dilatation in the 'coding' phase of the sentence presented in tinnitus patients was less than in the control group (p < 0.05). There was no difference between the groups for Matrix test scores (p > 0.05) Also, there was no statistically significant correlation between THI and Pupillometry components nor between MoCA (p > 0.05). ConclusionEven though tinnitus patients had normal hearing in the range of 0.125–20 kHz, their autonomic nervous system responses during listening differed from healthy subjects. This difference was interpreted for potential listening fatigue in tinnitus patients.

Effect of Stimulus Bandwidth on the Auditory Steady-State Response in Scalp- and Ear-EEG.

The auditory steady-state response (ASSR) enables hearing threshold estimation based on electroencephalography (EEG) recordings. The choice of stimulus type has an impact on both the detectability and the frequency specificity of the ASSR. Amplitude modulated pure tones provide the most frequency-specific ASSR, but responses to pure tones are weak. The ASSR can be enhanced by increasing the bandwidth of the stimulus, but this comes at the cost of a decrease in the frequency specificity of the measured response. The objective of the present study is to investigate the relationship between stimulus bandwidth and ASSR amplitude. The amplitude of ASSR was measured for five types of stimuli: 1 kHz pure tone and band-pass noise with 1/3, 1/2, 1, and 2 octave bandwidths centered at 1 kHz. All stimuli were amplitude modulated with a 40 Hz sinusoid. Responses to all stimulus types were measured at 30, 40, and 50 dB SL. ASSRs were measured concurrently using both conventional scalp-EEG and ear-EEG. Stimulus bandwidth and sound intensity were both found to have a significant effect on the ASSR amplitude for scalp- and ear-EEG recordings. In scalp-EEG ASSRs to all bandwidth stimuli were found to be significantly larger than ASSRs to pure tone at low sound intensity. At higher sound intensities, however, significantly larger responses were only obtained for 1- and 2-octave bandwidth stimuli. In ear-EEG, only the ASSR to 2 octave bandwidth stimulus was significantly larger than the ASSR to amplitude modulated pure tones. At low presentation levels, even small increases in stimulus bandwidth (1/3 and 1/2 octave) improve the detectability of ASSR in scalp-EEG with little or no impact on the frequency specificity. In comparison, a larger increase in stimulus bandwidth was needed to improve the ASSR detectability in the ear-EEG recordings.

Time-dependent effects of acoustic trauma and tinnitus on extracellular levels of amino acids in the inferior colliculus of rats

Chronic tinnitus is a debilitating condition with very few management options. Acoustic trauma that causes tinnitus has been shown to induce neuronal hyperactivity in multiple brain areas in the auditory pathway, including the inferior colliculus. This neuronal hyperactivity could be attributed to an imbalance between excitatory and inhibitory neurotransmission. However, it is not clear how the levels of neurotransmitters, especially neurotransmitters in the extracellular space, change over time following acoustic trauma and the development of tinnitus. In the present study, a range of amino acids were measured in the inferior colliculus of rats during acoustic trauma as well as at 1 week and 5 months post-trauma using in vivo microdialysis and high-performance liquid chromatography. Amino acid levels in response to sound stimulation were also measured at 1 week and 5 months post-trauma. It was found that unilateral exposure to a 16 kHz pure tone at 115 dB SPL for 1 h caused immediate hearing loss in all the animals and chronic tinnitus in 58 % of the animals. Comparing to the sham condition, extracellular levels of GABA were significantly increased at both the acute and 1 week time points after acoustic trauma. However, there was no significant difference in any of the amino acid levels measured between sham, tinnitus positive and tinnitus negative animals at 5 months post-trauma. There was also no clear pattern in the relationship between neurochemical changes and sound frequency/acoustic trauma/tinnitus status, which might be due to the relatively poorer temporal resolution of the microdialysis compared to electrophysiological responses.

Experimental and quantitative evaluation of frequency modulation caused by Doppler effect around high-speed moving sound source.

High-speed train noise remains a wayside environmental issue. For accurate noise prediction, the characteristics of a moving sound source must be revealed. In this work, the frequency modulation of sound waves emitted from a high-speed moving sound source was experimentally investigated. In the experiment, the sound field around a running train model emitting a 40 kHz pure tone was measured by an optical measurement technique, parallel phase-shifting interferometry, which can visualize instantaneous sound fields. For quantitative evaluation, a lens distortion correction was also developed and adopted for the visualization results. From the measured result of a sound source moving at a running speed of 280 km/h, the frequency modulation, known as the Doppler effect, was observed, and the measured frequency agreed well with the theoretical values.

An Exploratory Study of the Effect of Tinnitus on Listening Effort Using EEG and Pupillometry.

Previous behavioral studies on listening effort in tinnitus patients did not consider extended high-frequency hearing thresholds and had conflicting results. This inconsistency may be related that listening effort is not evaluated by the central nervous system (CNS) and autonomic nervous system (ANS), which are directly related to tinnitus pathophysiology. This study matches hearing thresholds at all frequencies, including the extended high-frequency and reduces hearing loss to objectively evaluate listening effort over the CNS and ANS simultaneously in tinnitus patients. Case-control study. University hospital. Sixteen chronic tinnitus patients and 23 matched healthy controls having normal pure-tone averages with symmetrical hearing thresholds were included. Subjects were evaluated with 0.125 to 20 kHz pure-tone audiometry, Montreal Cognitive Assessment Test (MoCA), Tinnitus Handicap Inventory (THI), Visual Analog Scale (VAS), electroencephalography (EEG), and pupillometry. Pupil dilation and EEG alpha band in the "coding" phase of the sentence presented in tinnitus patients was less than in the control group (p < .05). VAS score was higher in the tinnitus group (p < .01). Also, there was no statistically significant relationship between EEG and pupillometry components and THI or MoCA (p > .05). This study suggests that tinnitus patients may need to make an extra effort to listen. Also, pupillometry may not be sufficiently reliable to assess listening effort in ANS-related pathologies. Considering the possible listening difficulties in tinnitus patients, reducing the listening difficulties, especially in noisy environments, can be added to the goals of tinnitus therapy protocols.

WITHDRAWN: Listening handicap in tinnitus patients by controlling extended high frequencies - Effort or fatigue?

ObjectiveIn previous studies, the results regarding the presence of listening effort or fatigue in tinnitus patients were inconsistent. The reason for this inconsistency could be that extended high frequencies, which can cause listening handicap, were not considered. Therefore, this study aimed to evaluate the listening skills in tinnitus patients by matching the hearing thresholds at all frequencies, including the extended high frequency. MethodsEighteen chronic tinnitus patients and thirty matched healthy controls having normal pure-tone average with symmetrical hearing thresholds was included. Subjects were evaluated with 0.125-20 kHz pure-tone audiometry, Montreal cognitive assessment test (MoCA), Tinnitus Handicap Inventory (THI), Matrix Test, Pupillometry. ResultsPupil dilatation in the 'coding' phase of the sentence presented in tinnitus patients was less than in the control group (p<0.05). There was no difference between the groups for Matrix test scores (p> 0.05) Also, there was no statistically significant correlation between THI and Pupillometry components nor between MoCA (p>0.05). ConclusionThe results were interpreted for potential listening fatigue in tinnitus patients. Considering the possible listening handicap in tinnitus patients, reducing the listening difficulties especially in noisy environments, can be added to the goals of tinnitus therapy protocols.

Detection of the 40 Hz auditory steady-state response with optically pumped magnetometers

Magnetoencephalography (MEG) is a functional neuroimaging technique that noninvasively detects the brain magnetic field from neuronal activations. Conventional MEG measures brain signals using superconducting quantum interference devices (SQUIDs). SQUID-MEG requires a cryogenic environment involving a bulky non-magnetic Dewar flask and the consumption of liquid helium, which restricts the variability of the sensor array and the gap between the cortical sources and sensors. Recently, miniature optically pumped magnetometers (OPMs) have been developed and commercialized. OPMs do not require cryogenic cooling and can be placed within millimeters from the scalp. In the present study, we arranged six OPM sensors on the temporal area to detect auditory-related brain responses in a two-layer magnetically shielded room. We presented the auditory stimuli of 1 kHz pure-tone bursts with 200 ms duration and obtained the M50 and M100 components of auditory-evoked fields. We delivered the periodic stimuli with a 40 Hz repetition rate and observed the gamma-band power changes and inter-trial phase coherence of auditory steady-state responses at 40 Hz. We found that the OPM sensors have a performance comparable to that of conventional SQUID-MEG sensors, and our results suggest the feasibility of using OPM sensors for functional neuroimaging and brain–computer interface applications.

Opto‐ and Chemogenetic Dissection of Ictal Apnea Neural Circuitry

Sudden Unexpected Death in Epilepsy (SUDEP) is defined as the sudden, unexpected and unexplained death of a person with epilepsy and accounts for between 8 and 17% of epilepsy‐related deaths, rising to 50% for patients with refractory epilepsy. In a mouse model of SUDEP, we have recently shown that death is due to seizure‐induced respiratory arrest. In addition, apnea is initiated during the tonic phase and tonic respiratory muscle contraction is a possible mechanism of apnea. In the present study, we explore 1) whether tonic activity of the inspiratory rhythm generator in the brainstem and/or 2) upper motor neuron activity in the motor cortex drives ictal apnea.We recorded video, electrocorticogram (ECoG), electrocardiogram (ECG), and breathing via whole body plethysmography in adult mice carrying the human SCN8A encephalopathy mutation p.Asn1768Asp (N1768D; “D/+ mice”) during audiogenic seizures. This mutation was identified from a patient that died from SUDEP and D/+ mice have severe convulsive seizures with apnea and many suffer seizure‐induced death.To test the hypothesis that tonic activity from the inspiratory oscillator results in apnea, we implanted fiberoptic ferrules bilaterally into the Bötzinger Complex (BötC) of mice that express Channelrhodopsin2 (ChR2) under the vesicular GABA transporter (VGAT; “VGAT‐ChR2” mice) that were crossed with D/+ mice (Fig. 1A &amp; B). The goal of the experiment is to photostimulate BötC during ictal apnea to inhibit tonic inspiratory activity and produce expiration (Fig. 1C). Seizures were evoked using a 15 kHz pure tone, as we have done before (Fig. 1D). Trains of light pulses (50 ms pulses, 5 mW of 473 nm light) were evoked repetitively during ictal apnea (Fig. 1E &amp; F). However, this did not recover normal breathing rhythm and apnea duration was no different for any photostimulation paradigm versus control (p = 0.7892, F = 0.1747, One‐Way ANOVA; Fig. 1G). Although breathing was not affected during seizures, the effects on baseline breathing were substantial; for example, inspiration was inhibited for a full 10 second photostimulation train (Fig. 1H).To test the necessity of ictal activity from upper motor neurons in the motor cortex are required for generating ictal apnea, we expressed iDREADD receptors in cortical excitatory neurons of D/+ mice and injected CNO i.p. prior to inducing seizures with a 15 kHz pure tone (Fig. 2A). Under control conditions, seizures presented with the usual tonic phase apnea and spike wave discharges (SWDs) in the motor cortex (Fig. 2B). CNO was able to robustly inhibit the SWDs, but the tonic phase and apnea were not affected (Figs. 2C‐E). The effect of 3 mg/kg CNO on ECoG power was significantly greater than the effect on apnea (p = 0.0059, paired t‐test).In sum, we found that the core inspiratory oscillator circuitry in the brainstem is likely bypassed to create tonic inspiratory activity. Furthermore, inhibition of cortical upper motor neurons has no effect on apnea. Thus, our interpretation is that other pools of upper motor neurons must drive the tonic inspiratory activity and apnea.

Better speech-in-noise comprehension is associated with enhanced neural speech tracking in older adults with hearing impairment

The alignment between low-frequency activity in the brain and slow acoustic modulations in the speech signal depicts a core principle in present theories of speech perception—a process referred to as ‘neural speech tracking’. While most older adults, particularly those with highly prevalent age-related hearing loss, have difficulties with speech perception and comprehension, the impact of hearing loss on neural speech tracking is still unclear. In this study we investigated the effects of pure-tone hearing loss and different types of background noise on the neural tracking response in a large sample of older adults (N = 101). Furthermore, we examined whether the neural tracking response was predictive for speech comprehension. For this purpose, we obtained scalp EEG from our participants who had varying degrees of pure-tone hearing loss (7.5–59.6 dB HL for .5–8 kHz pure tones) while they listened to sentences in quiet, pink and multi-talker babble noise. Speech tracking was quantified by computing the cross-correlation between the EEG signal and the amplitude envelope of the sentences heard. A higher degree of pure-tone hearing loss was associated with greater neural speech tracking (i.e., greater cross-correlation). Additionally, neural speech tracking showed a positive association with speech comprehension. This relationship was modulated by the degree of pure-tone hearing loss with hearing-impaired participants benefitting more from greater neural speech tracking. Our results highlight the potential of neural speech tracking as an objective measure of speech comprehension and as a possible target mechanism for clinical interventions such as neurofeedback. Furthermore, the interaction between speech tracking and pure-tone hearing loss suggests a compensatory mechanism by which the hearing-impaired rely more on slow amplitude modulations in the speech signal.

Effect of age on acoustic reflex thresholds in neonates and infants with normal hearing

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; High frequency (1000 Hz) probe tone holds substantial promise for carrying out acoustic reflexes in neonates and infants. A limited number of studies indicates that acoustic reflex thresholds (ART) also change significantly with age as the newborn hearing system matures. However, there is a need for obtaining more data before using it in a clinical population. The aim was to investigate effect of age of infants on ARTs. Effect of activator signal was also explored. &lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; ARTs were monitored using a 1 kHz probe tone for the 500 Hz, 1 kHz, 2 kHz, and 4 kHz pure tone activators in neonates and infants in the age range of 6 to 8 weeks were analysed.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results&lt;/strong&gt;: The mean ARTs for neonates were lower compared to infants. Results of repeated measure ANOVA showed that there was a statistically significant age effect. Also, ARTs for high frequency activator signals were significantly higher than the ARTs for low frequency signals.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The acoustic reflexes can be elicited for 500, 1000, 2000, and 4000 Hz when monitored using a 1000 Hz probe tone. There is an effect of age and activator signal on the acoustic reflex threshold. The data obtained in the present study can serve as normative for 0-1-week neonates and 6-8-weeks infants.&lt;/p&gt;

Characteristics at different frequencies of hearing loss in noise exposure workers of the automobile manufacturing industry

Objective: To analyze the effects of noise exposure on the hearing at different frequencies in workers from the automobile manufacturing industry. Methods: A total of 4723 noise workers in a large automobile manufacturing company in Guangzhou were chosen as the research object by using judgment sampling method between April and July, 2018, and carried out 0.5, 1.0, 2.0, 3.0, 4.0 and 6.0 kHz pure tone audiometry threshold to analyze the characteristics of the status of hearing loss at different frequencies and its relationship with the noise exposure time. Results: The detection rate of hearing loss in noise-exposed workers was 29.8% (1406/4723) . Among them, the binaural hearing loss was 21.2% (999/4723) , and single unilateral hearing loss accounted for 8.6% (407/4723) . The hearing loss detection rate of right ear was higher than that of the left ear (P<0.05) , especially in the 6.0 kHz (P<0.001) . The detection rate of increased speech frequency hearing threshold was 1.9% (90/4723) , and the detection rate of increased high-frequency hearing threshold was 28.9% (1366/4723) . The detection rate of increased threshold in both the left and the right ear increased with the increase of frequency (P<0.001) , the increased hearing threshold was the highest at the frequency of 6.0 kHz. The auditory threshold of left ear in 0.5 kHz were higher than that of right ear at the same frequency (P<0.05) . The detection rate of hearing loss increased with the increase of noise exposure time (P<0.001) , and the increased threshold of 3.0, 4.0 and 6.0 kHz from workers increased with the increase of noise exposure time (P<0.001) . Conclusion: There is a significant increased threshold in workers exposed to noise frequency of 6.0 kHz, right ear is more easily damaged than left ear, there is a dose-response relationship for the noise exposure time and high-frequency hearing loss.

Lateralization asymmetry in right/left ears of elderly individuals with respect to various sound pressure levels

The authors have previously reported that elderly individuals have asymmetrical right and left ear performance when they horizontally lateralize a 1 kHz pure tone with Interaural Time Differences (ITDs). In the previous experiment, the Sound Pressure Level (SPL) was set to 60.0 dB(A), but in the present experiment, conditions were set every 1.5 dB(A) from 54.0 dB(A) to 66.0 dB(A) in order to investigate the effect of SPLs. Participants were 18 elderly and 16 young adults. For ITDs, 8 conditions were set to lead the right or left ear and those were 0.2, 0.4, 0.6, and 0.8 ms, respectively. The frequencies of the sounds were 2 types: 1 kHz and 0.5 + 2 kHz. As a result, for a 1 kHz pure tone, the elderly individuals had asymmetry in right and left ear performance. It was more likely that the sound leading in the right ear was referred to as left. The lower the SPL, the more confusion existed between the right and left. Even in the elderly, confusion was rare for a sound of 0.5 + 2 kHz. Younger individuals rarely had confusion between the right and left ears for all conditions.

Effects of Cognitive Load on Pure-Tone Audiometry Thresholds in Younger and Older Adults.

Cognitive load (CL) impairs listeners' ability to comprehend sentences, recognize words, and identify speech sounds. Recent findings suggest that this effect originates in a disruption of low-level perception of acoustic details. Here, we attempted to quantify such a disruption by measuring the effect of CL (a two-back task) on pure-tone audiometry (PTA) thresholds. We also asked whether the effect of CL on PTA was greater in older adults, on account of their reduced ability to divide cognitive resources between simultaneous tasks. To specify the mechanisms and representations underlying the interface between auditory and cognitive processes, we contrasted CL requiring visual encoding with CL requiring auditory encoding. Finally, the link between the cost of performing PTA under CL, working memory, and speech-in-noise (SiN) perception was investigated and compared between younger and older participants. Younger and older adults (44 in each group) did a PTA test at 0.5, 1, 2, and 4 kHz pure tones under CL and no CL. CL consisted of a visual two-back task running throughout the PTA test. The two-back task involved either visual encoding of the stimuli (meaningless images) or subvocal auditory encoding (a rhyme task on written nonwords). Participants also underwent a battery of SiN tests and a working memory test (letter number sequencing). Younger adults showed elevated PTA thresholds under CL, but only when CL involved subvocal auditory encoding. CL had no effect when it involved purely visual encoding. In contrast, older adults showed elevated thresholds under both types of CL. When present, the PTA CL cost was broadly comparable in younger and older adults (approximately 2 dB HL). The magnitude of PTA CL cost did not correlate significantly with SiN perception or working memory in either age group. In contrast, PTA alone showed strong links to both SiN and letter number sequencing in older adults. The results show that CL can exert its effect at the level of hearing sensitivity. However, in younger adults, this effect is only found when CL involves auditory mental representations. When CL involves visual representations, it has virtually no impact on hearing thresholds. In older adults, interference is found in both conditions. The results suggest that hearing progresses from engaging primarily modality-specific cognition in early adulthood to engaging cognition in a more undifferentiated way in older age. Moreover, hearing thresholds measured under CL did not predict SiN perception more accurately than standard PTA thresholds.

Minimal and Mild Hearing Loss in Children: Association with Auditory Perception, Cognition, and Communication Problems.

"Minimal" and "mild" hearing loss are the most common but least understood forms of hearing loss in children. Children with better ear hearing level as low as 30 dB HL have a global language impairment and, according to the World Health Organization, a "disabling level of hearing loss." We examined in a population of 6- to 11-year-olds how hearing level ≤40.0 dB HL (1 and 4 kHz pure-tone average, PTA, threshold) is related to auditory perception, cognition, and communication. School children (n = 1638) were recruited in 4 centers across the United Kingdom. They completed a battery of hearing (audiometry, filter width, temporal envelope, speech-in-noise) and cognitive (IQ, attention, verbal memory, receptive language, reading) tests. Caregivers assessed their children's communication and listening skills. Children included in this study (702 male; 752 female) had 4 reliable tone thresholds (1, 4 kHz each ear), and no caregiver reported medical or intellectual disorder. Normal-hearing children (n = 1124, 77.1%) had all 4 thresholds and PTA <15 dB HL. Children with ≥15 dB HL for at least 1 threshold, and PTA <20 dB (n = 245, 16.8%) had minimal hearing loss. Children with 20 ≤PTA <40 dB HL (n = 88, 6.0%) had mild hearing loss. Interaural asymmetric hearing loss ( left PTA - right PTA ≥10 dB) was found in 28.9% of those with minimal and 39.8% of those with mild hearing loss. Speech perception in noise, indexed by vowel-consonant-vowel pseudoword repetition in speech-modulated noise, was impaired in children with minimal and mild hearing loss, relative to normal-hearing children. Effect size was largest (d = 0.63) in asymmetric mild hearing loss and smallest (d = 0.21) in symmetric minimal hearing loss. Spectral (filter width) and temporal (backward masking) perceptions were impaired in children with both forms of hearing loss, but suprathreshold perception generally related only weakly to PTA. Speech-in-noise (nonsense syllables) and language (pseudoword repetition) were also impaired in both forms of hearing loss and correlated more strongly with PTA. Children with mild hearing loss were additionally impaired in working memory (digit span) and reading, and generally performed more poorly than those with minimal loss. Asymmetric hearing loss produced as much impairment overall on both auditory and cognitive tasks as symmetric hearing loss. Nonverbal IQ, attention, and caregiver-rated listening and communication were not significantly impaired in children with hearing loss. Modeling suggested that 15 dB HL is objectively an appropriate lower audibility limit for diagnosis of hearing loss. Hearing loss between 15 and 30 dB PTA is, at ~20%, much more prevalent in 6- to 11-year-old children than most current estimates. Key aspects of auditory and cognitive skills are impaired in both symmetric and asymmetric minimal and mild hearing loss. Hearing loss <30 dB HL is most closely related to speech perception in noise, and to cognitive abilities underpinning language and reading. The results suggest wider use of speech-in-noise measures to diagnose and assess management of hearing loss and reduction of the clinical hearing loss threshold for children to 15 dB HL.

Changes in sound lateralization ability of elderly individuals when the onset conditions of pure tone of 1 kHz are varied

In our previous experiments, we found that the recognition of onset of the sound with Interaural Time Differences (ITDs) was inferior for the elderly in comparison with the younger participants. In the present experiment, we have conducted a test using 17 elderly and 16 young participants, in which the duration of the cosine-shaped onset of a 1 kHz pure tone that lasted one second was changed to 4 types of 1, 2, 5 and 10 ms. In addition, 9 types of ITDs (0.2, 0.4, 0.6, 0.8 ms leading to the left or right ear besides the same condition to both ears) were set. In the experiment, a reference sound indicating the front was presented followed by a test sound. Participants responded with 3 choices of the direction of the test sound compared with the reference sound: “Left,” “Same,” or “Right.” The following findings were obtained. (1) Elderly participants are more likely than younger participants to poorly lateralize when sound precedes to the right ear first than to the left. (2) For the elderly participants, the longer the cosine-shape of the onset is, the more likely direction is to be erroneously recognized.In our previous experiments, we found that the recognition of onset of the sound with Interaural Time Differences (ITDs) was inferior for the elderly in comparison with the younger participants. In the present experiment, we have conducted a test using 17 elderly and 16 young participants, in which the duration of the cosine-shaped onset of a 1 kHz pure tone that lasted one second was changed to 4 types of 1, 2, 5 and 10 ms. In addition, 9 types of ITDs (0.2, 0.4, 0.6, 0.8 ms leading to the left or right ear besides the same condition to both ears) were set. In the experiment, a reference sound indicating the front was presented followed by a test sound. Participants responded with 3 choices of the direction of the test sound compared with the reference sound: “Left,” “Same,” or “Right.” The following findings were obtained. (1) Elderly participants are more likely than younger participants to poorly lateralize when sound precedes to the right ear first than to the left. (2) For the elderly participants, ...

Acoustic response characteristics of posterior intralaminar nucleus of auditory thalamus in mice

Objective: To study the response characteristics of the posterior intralaminar nucleus (PIN) of auditory thalamus in VGluT2-Cre transgenic adult mice when exposed to white noise and 10K pure tone stimulation. Methods: All adult male Vglut2-Cre mice (8-12 weeks) were used in this study between Oct, 2017 and Oct, 2018. Using the calcium signal fiber photometry method, optic fiber was employed to locate on PIN by injecting AAV-hSyn-DIO-GCaMP6m virus, and thereafter, the activity of the target cluster neurons during different acoustic stimuli was recorded. Matlab was used for data processing and statistical analysis. Results: (1)In both white noise and 10 kHz pure tone as a continuous three-second stimulation, the peak amplitude of calcium signal activity generated in PIN by white noise was superior to that of pure tone, the statistic result showed significantly difference (n=6, t=2.404, P=0.037 1) . (2)In addition, when white noise and 10K pure tone played as consecutive 3 or 5 pips within three-second stimulation, the stimulus-following ability in a consecutive 3 pulses play within 3 seconds was far better than a consecutive 5 pips play within 3 seconds (in both white noise and 10 kHz pure tone), yet consecutive 3 pips play showed greater signal attenuation speed than that in consecutive 5 pips play, the statistic result showed significantly difference (n=6, t=2.748 P=0.033 4) .(3)Regardless of the intra-group comparisons between white noise and 10 kHz pure tone stimulation, PIN showed better signal response in a consecutive 3 pips play than consecutive 5 pips play or a continuous three-second stimulation. When came to the statistical analysis, the acoustic response degree of a continuous three-second stimulation was an intermediate between two others, both consecutive 3 or 5 pips play showed significantly difference. Conclusions: The results suggest that under the same acoustic intensity, VGluT2-Cre transgenic adult mice's PIN shows greater signal response in white noise than pure tone. PIN shows greater signal attenuation to repetition play of 10 kHz pure tone, which implies PIN shows stronger adaptation to 10 kHz pure tone than to white noise. Lastly, PIN is more responsive to a complex sound information (white noise) than to simple sound information (pure tone).

The effects of age and sex on rates of hearing loss for pure tones varying in duration

Mice are frequently used to study and model presbycusis due to similarities in the human and mouse cochleae and in genetic makeup. Most of the previous research on presbycusis used electrophysiological measures of hearing in mice, leading to an underrepresentation of behavioral experiments in the literature on mouse aging. The goal of the current research was to fill this gap by behaviorally measuring audiograms and temporal summation functions in aging mice. Adult mice were trained and tested using an accelerated longitudinal design. Mice were trained on a detection task using operant conditioning procedures with positive reinforcement. Audiograms were constructed using thresholds for 8, 16, 24, 42, and 64 kHz pure tones. Temporal summation functions were constructed for 16 and 64 kHz pure tones ranging from 20 to 800 ms in duration. The results revealed that mice retain pure tone hearing late into their lifespan, with high-frequency hearing loss preceding low-frequency hearing loss. Mice also benefit from increases in the duration of pure tones; however. this benefit decreases with age. Generally, male mice lose hearing at a faster rate than females. These results highlight the importance of measuring hearing in awake, trained, behaving subjects when comparing presbycusis across species.

Significance of 1 kHz Pure-tone Threshold in Acute Low-frequency Sensorineural Hearing Loss.

To analyze risk factors for acute low-frequency hearing loss (ALFHL), and compare treatment outcomes in the presence or absence of such risk factors. A case series featuring retrospective chart review. An academic university hospital. We included 170 ALFHL patients without vertigo. All of the patients received one of four treatments: low-dose steroid (LD-steroid), high-dose steroid (HD-steroid), LD-steroid and diuretics (LD-combination therapy), and ITDI (intratympanic dexamethasone injection) and diuretics (ITDI-combination therapy). To identify risk factors, we reviewed the clinical features of patients such as age, sex, chief complaint, accompanying symptoms, diabetes, hypertension, time from disease onset, the extent of hearing loss, treatment methods, and 1 kHz involvement. ALFHL was diagnosed based on the average hearing loss >30 dB at 250 and 500 Hz. The overall rates of hearing recovery were 70-80% in the four treatment groups. In terms of the prognosis of ALFHL patients, we found that a longer time from disease onset and 1 kHz involvement were independent risk factors for poor prognosis. In addition, we compared treatment outcomes of four treatment methods in the presence or absence of risk factors. In ALFHL patients with risk factors, we found statistically significant differences (p = 0.042) among treatment methods; effectiveness ranged in the order if ITDI-combination therapy, LD-combination therapy, HD-steroid, and LD-steroid. Risk factors for poor hearing recovery in ALFHL included longer symptom duration and 1 kHz involvement. In ALFHL with such risk factors, combination therapy was more effective than oral steroid therapy.