Bone conducted cervical vestibular evoked myogenic potentials: comparison of tone burst stimulus vs chirp stimulus.

PURPOSE: Vestibular evoked myogenic potential (VEMP) is a test used to evaluate the function of otolith organs. In healthy individuals, air-conducted (AC) responses are obtained, whereas, in conductive hearing loss, the inability to transmit the signal well enough with AC stimuli has led to the need for bone-conducted (BC) stimuli. This study aimed to compare 500 Hz Chirp and Tone Burst stimuli in terms of latency and amplitude in BC cVEMP. METHODS: This prospective observational case control study included 35 healthy participants (70 ears) between the age of 20-50. Participants underwent VEMP testing with BC 500 Hz Tone Burst stimulus and 500 Hz narrow band Chirp stimulus without changing the position of the bone conducted vibrator. The intensity of the stimuli was 50 dB nHL. RESULTS: Response rate of 500 Hz TB Stimulus was 51.4% and 95.7% in Chirp stimulus. It was observed that significantly more responses were obtained with Chirp stimulus than TB stimulus (p < 0.001). In terms of p1 latency, n1 latency, both latencies were significantly shorter in Chirp stimulus (p < 0.001). p1n1 amplitude was found significantly larger in Chirp stimulus (p < 0.001). CONCLUSION: Compared to 500 Hz TB stimulus, 500 Hz Chirp stimulus results in a higher response rate, larger p1n1 amplitude, and shorter p1 and n1 latency. A higher response rate may provide a more accurate assessment of otolith organs, reducing false negatives due to signal transmission in patients.

Investigating the Effects of Level-Specific CE-Chirp on Auditory Brainstem Response Waves in Normal Hearing Infants.

Background: Auditory brainstem response (ABR) to the level-specific (LS) CE-Chirp has been reported to provide optimum neural synchrony along cochlear partitions, theoretically improving ABR waveform resolution. Despite this promising finding, limited studies have been conducted to contrast the results between LS CE-Chirp and Click stimuli. The current study aimed to compare the results of ABR between the two stimuli (Click and LS CE-Chirp). Method: Sixty-seven normal-hearing infants, both with and without risk factors, aged less than 7 months old, participated in this study. The ABR test was conducted at 70 dBnHL using 33.3 stimulus repetition rates with both Click and LS CE-Chirp stimuli. The signal averaging was stopped at a maximum fixed signal average of 2,500 sweeps. Data were statistically compared between the two stimuli using the Wilcoxon signed-rank test. Results: The waves I and V ABRs elicited by LS CE-Chirp exhibited significantly larger amplitudes than the Click stimulus. However, the amplitude of wave III and absolute latencies were similar in both stimuli at a supra-threshold level. Conclusion: LS CE-Chirp has the advantage of larger amplitudes than the ABR from Click at the supra-threshold level (70 dBnHL) in normal-hearing infants.

Image Super Resolution-Based Channel Estimation for Orthogonal Chirp Division Multiplexing on Shallow Water Underwater Acoustic Communications.

Orthogonal chirp division multiplexing (OCDM) offers a promising modulation technology for shallow water underwater acoustic (UWA) communication systems due to multipath fading resistance and Doppler resistance. To handle the various channel distortions and interferences, obtaining accurate channel state information is vital for robust and efficient shallow water UWA communication. In recent years, deep learning has attracted widespread attention in the communication field, providing a new way to improve the performance of physical layer communication systems. In this paper, the pilot-based channel estimation is transformed into a matrix completion problem, which is mathematically equivalent to the image super-resolution problem arising in the field of image processing. Simulation results show that the deep learning-based method can improve the channel distortion, outperforming the equalization performed by traditional estimator, the performance of Bit Error Rate is improved by 2.5 dB compared to the MMSE method in OCDM system. At the 7.5 to 20 dB region, it achieves better bit error rate performance than OFDM systems, and the bit error rate is reduced by approximately 53% compared to OFDM when the SNR value is 20, which is very useful in shallow water UWA channels with multipath extension and severe time-varying characteristics.

Spindle chirp and other sleep oscillatory features in young children with autism.

OBJECTIVES: To determine whether spindle chirp and other sleep oscillatory features differ in young children with and without autism. METHODS: Automated processing software was used to re-assess an extant set of polysomnograms representing 121 children (91 with autism [ASD], 30 typically-developing [TD]), with an age range of 1.35-8.23 years. Spindle metrics, including chirp, and slow oscillation (SO) characteristics were compared between groups. SO and fast and slow spindle (FS, SS) interactions were also investigated. Secondary analyses were performed assessing behavioural data associations, as well as exploratory cohort comparisons to children with non-autism developmental delay (DD). RESULTS: Posterior FS and SS chirp was significantly more negative in ASD than TD. Both groups had comparable intra-spindle frequency range and variance. Frontal and central SO amplitude were decreased in ASD. In contrast to previous manual findings, no differences were detected in other spindle or SO metrics. The ASD group displayed a higher parietal coupling angle. No differences were observed in phase-frequency coupling. The DD group demonstrated lower FS chirp and higher coupling angle than TD. Parietal SS chirp was positively associated with full developmental quotient. CONCLUSIONS: For the first time spindle chirp was investigated in autism and was found to be significantly more negative than in TD in this large cohort of young children. This finding strengthens previous reports of spindle and SO abnormalities in ASD. Further investigation of spindle chirp in healthy and clinical populations across development will help elucidate the significance of this difference and better understand this novel metric.

Control of endothelial cell function and arteriogenesis by MEG3:EZH2 epigenetic regulation of integrin expression.

Epigenetic processes involving long non-coding RNAs regulate endothelial gene expression. However, the underlying regulatory mechanisms causing endothelial dysfunction remain to be elucidated. Enhancer of zeste homolog 2 (EZH2) is an important rheostat of histone H3K27 trimethylation (H3K27me3) that represses endothelial targets, but EZH2 RNA binding capacity and EZH2:RNA functional interactions have not been explored in post-ischemic angiogenesis. We used formaldehyde/UV-assisted crosslinking ligation and sequencing of hybrids and identified a new role for maternally expressed gene 3 (MEG3). MEG3 formed the predominant RNA:RNA hybrid structures in endothelial cells. Moreover, MEG3:EZH2 assists recruitment onto chromatin. By EZH2-chromatin immunoprecipitation, following MEG3 depletion, we demonstrated that MEG3 controls recruitment of EZH2/H3K27me3 onto integrin subunit alpha4 (ITGA4) promoter. Both MEG3 knockdown or EZH2 inhibition (A-395) promoted ITGA4 expression and improved endothelial cell migration and adhesion to fibronectin in vitro. The A-395 inhibitor re-directed MEG3-assisted chromatin remodeling, offering a direct therapeutic benefit by increasing endothelial function and resilience. This approach subsequently increased the expression of ITGA4 in arterioles following ischemic injury in mice, thus promoting arteriogenesis. Our findings show a context-specific role for MEG3 in guiding EZH2 to repress ITGA4. Novel therapeutic strategies could antagonize MEG3:EZH2 interaction for pre-clinical studies.

Optimizing ChIRP-MS for Comprehensive Profiling of RNA-Protein Interactions in Arabidopsis thaliana: A Telomerase RNA Case Study.

The current repertoire of methods available for studying RNA-protein interactions in plants is somewhat limited. Employing an RNA-centric approach, particularly with less abundant RNAs, presents various challenges. Many of the existing methods were initially designed for different model systems, with their application in plants receiving limited attention thus far. The Comprehensive Identification of RNA-Binding Proteins by Mass Spectrometry (ChIRP-MS) technique, initially developed for mammalian cells, has been adapted in this study for application in Arabidopsis thaliana. The procedures have been meticulously modified and optimized for telomerase RNA, a notable example of a low-abundance RNA recently identified. Following these optimization steps, ChIRP-MS can serve as an effective screening method for identifying candidate proteins interacting with any target RNA of interest.

Ictal fast activity chirps as markers of the epileptogenic zone.

The identification of the epileptogenic zone (EZ) boundaries is crucial for effective focal epilepsy surgery. We verify the value of a neurophysiological biomarker of focal ictogenesis, characterized by a low-voltage fast-activity ictal pattern (chirp) recorded with intracerebral electrodes during invasive presurgical monitoring (stereoelectroencephalography [SEEG]). The frequency content of SEEG signals was retrospectively analyzed with semiautomatic software in 176 consecutive patients with focal epilepsies that either were cryptogenic or presented with discordant anatomoelectroclinical findings. Fast activity seizure patterns with the spectrographic features of chirps were confirmed by computer-assisted analysis in 95.4% of patients who presented with heterogeneous etiologies and diverse lobar location of the EZ. Statistical analysis demonstrated (1) correlation between seizure outcome and concordance of sublobar regions included in the EZ defined by visual analysis and chirp-generating regions, (2) high concordance in contact-by contact analysis of 68 patients with Engel class Ia outcome, and (3) that discordance between chirp location and the visually outlined EZ correlated with worse seizure outcome. Seizure outcome analysis confirms the fast activity chirp pattern is a reproducible biomarker of the EZ in a heterogeneous group of patients undergoing SEEG.

Rapid hearing threshold assessment with modified auditory brainstem response protocols in dogs.

Introduction: Auditory brainstem response (ABR) is the gold standard for hearing testing in dogs. ABR is commonly used in puppies to diagnose congenital sensorineural deafness. Long test times limit the use for a more comprehensive hearing screening in veterinary practice. This study aimed to establish a super-fast hearing screening protocol in dogs. Methods: Hearing thresholds were routinely measured with a mobile device designed for newborn hearing screening in 90 dogs. We introduced modifications of the ABR protocol, e. g., a binaural test mode, higher stimulus rates, a broadband chirp stimulus, and an algorithm for automatic peak V detection in a stepwise fashion. Hearing thresholds were then measured with fast protocols utilizing either 30 Hz click or 90 Hz broadband chirp stimuli with 80, 60, 40, 30, 20, 10, 0 and -10 dBnHL stimulation intensities. Interrater reliability, agreement between click and chirp hearing thresholds and correlations with clinical characteristics of the dogs were assessed. Results: Using all innovations, the test time for hearing threshold assessment in both ears was reduced to 1.11 min (mean). The chirp stimulus accentuated both, peak V and the subsequent trough, which are essential features for judgement of the hearing threshold, but preceding peaks were less conspicuous. Interrater reliability and agreement between click and chirp hearing threshold was excellent. Dogs >10 years of age and dogs with abnormal hearing score or otitis score had significantly higher hearing thresholds than younger dogs (p ≤ 0.001) or dogs without abnormalities (p < 0.001). Conclusion: The results demonstrate that modifications in ABR protocols speed-up test times significantly while the quality of the recordings for hearing threshold assessment is maintained. Modified ABR protocols enable super-fast hearing threshold assessment in veterinary practice.

Correlation Analysis and Comparison of Adult CE-Chirp ABR Response Threshold and Pure Tone Hearing Threshold.

OBJECTIVES: To study the application of CE-Chirp in the evaluation of hearing impairment in forensic medicine by testing the auditory brainstem response (ABR) in adults using CE-Chirp to analyze the relationship between the V-wave response threshold of CE-Chirp ABR test and the pure tone hearing threshold. METHODS: Subjects (aged 20-77 with a total of 100 ears) who underwent CE-Chirp ABR test in Changzhou De'an Hospital from January 2018 to June 2019 were selected to obtain the V-wave response threshold, and pure tone air conduction hearing threshold tests were conducted at 0.5, 1.0, 2.0 and 4.0 kHz, respectively, to obtain pure tone listening threshold. The differences and statistical differences between the average pure tone hearing threshold and V-wave response threshold were compared in different hearing levels and different age groups. The correlation, differences and statistical differences between the two tests at each frequency were analyzed for all subjects. The linear regression equation for estimating pure tone hearing threshold for all subjects CE-Chirp ABR V-wave response threshold was established, and the feasibility of the equation was tested. RESULTS: There was no statistical significance in the CE-Chirp ABR response threshold and pure tone hearing threshold difference between different hearing level groups and different age groups (P>0.05). There was a good correlation between adult CE-Chirp ABR V-wave response threshold and pure tone hearing threshold with statistical significance (P<0.05), and linear regression analysis showed a significant linear correlation between the two (P<0.05). CONCLUSIONS: The use of CE-Chirp ABR V-wave response threshold can be used to evaluate subjects' pure tone hearing threshold under certain conditions, and can be used as an audiological test method for forensic hearing impairment assessment.

Supra-Threshold LS CE-Chirp Auditory Brainstem Response in the Elderly.

INTRODUCTION: Aging deteriorates peripheral and central auditory structures and functions. In elders, for an accurate audiological evaluation, it is important to explore beyond the cochlear receptor. Audiograms provide an estimation of hearing thresholds, while the amplitudes and latencies of supra-threshold auditory brainstem response (ABR) can offer noninvasive measures of the auditory pathways functioning. Regarding ABR, in young populations, level-specific chirp (LS CE-chirp) stimulus has been proposed as an alternative synchronizing method to obtain larger ABR responses than those evoked by clicks. However, the supra-threshold characteristics of chirp evoked ABR, and their association to hearing thresholds is relatively unknown in the elderly. The aim of this study was to evaluate supra-threshold LS CE-chirp ABRs in an aged population by comparing their features with click ABRs, and evaluating their relationship with audiometric hearing thresholds. METHODS: We carried out a cross-sectional study to characterize the hearing of 125 adults aged over 65 years. We determined the audiometric hearing thresholds and supra-threshold ABRs elicited by LS CE-chirp and click stimuli at 80 dB nHL. We evaluated associations by means of partial correlations and covariate adjustment. We performed specific frequencies' analysis and subgroup analysis per hearing level. RESULTS: Wave V responses had significantly shorter latencies and larger amplitudes when elicited by LS CE-chirp as compared to click-evoked responses. Audiometric hearing thresholds correlated with age, but ABR characteristics did not. We found mild correlations between hearing thresholds and ABR characteristics, predominantly at higher frequencies and with chirp. We found scarce evidence of correlation between ABR characteristics and the average of behavioral hearing thresholds between 0.5 to 4 kHz (0.5-4 kHz PTA). After subgroup analysis according to the hearing level, no stronger or more significant correlations were found between ABR characteristics and 0.5-4 kHz PTA. DISCUSSION: In this study, we found that supra-threshold LS CE-chirp ABR presented some of the previously described similitudes and differences with supra-threshold click ABR in younger populations. Although, the average amplitude and latency of wave V evoked by LS CE-chirp were larger and faster than those evoked by clicks, these results should be taken with caution at the individual level, and further studies are required to state that LS CE-chirp ABRs are better than click ABRs in elders for clinical evaluations. We did not find consistent associations between hearing thresholds and supra-threshold wave V features, suggesting that these measures should be considered independently in the elderly.

A high-resolution time-frequency analysis technique based on bi-directional squeezing and its application in fault diagnosis of rotating machinery.

Most of the signals in the field of industrial engineering are nonstationary signals, and the accurate description of the time-frequency (TF) characteristics of nonstationary signals is important for the advancement of industrial engineering. Instantaneous frequency (IF) and group delay (GD) are common TF features used to describe nonstationary signals. Time-reassigned synchrosqueezing transform and synchrosqueezing transform are two TF analysis tools that can accurately characterize the GD and IF of nonstationary signals by squeezing the TF coefficients in the time direction and frequency direction, respectively. However, it is difficult for such two techniques to accurately characterize IF and GD simultaneously. A novel method called time-frequency squeezing transform is introduced in this paper to conquer this drawback. The technique first uses the short-time Fourier transform to calculate the time-frequency representation (TFR) of a signal, and then divides the TFR into two parts according to a chirp rate estimator. The subdivided TFR parts are then squeezed in the frequency and time directions to accurately characterize the IF and GD, respectively, and the two squeezed results are added to form a high-resolution result. The effectiveness of the proposed technique is demonstrated with numerical and experimental signals.

Research on High Performance Methane Gas Concentration Sensor Based on Pyramid Beam Splitter Matrix.

Methane gas concentration detection faces the challenges of increasing accuracy and sensitivity, as well as high reliability in harsh environments. The special design of the optical path structure of the sensitive element provides an opportunity to improve methane gas concentration detection. In this study, the optical path structure of the sensitive element was newly designed based on the Pyramidal beam splitter matrix. The infrared light source was modulated by multi-frequency point-signal superimposed modulation technology. At the same time, concentration detection results and confidence levels were calculated using the four-channel methane gas concentration detection algorithm based on spectral refinement. Through the experiment, it was found that the sensor enables the full-range measurement of CH4; at the lower explosive limit (LEL, CH4 LEL of 5%), the reliability level is 0.01 parts-per-million (PPM), and the limit of detection is 0.5 ppm. The sensor is still capable of achieving PPM-level detections under extreme conditions in which the sensor's optical window is covered by two-thirds and humidity is 85% or dust concentration is 100 mg/m3. Those improve the sensitivity, robustness, reliability, and accuracy of the sensor.

Exploration and bioinformatic prediction for profile of mRNA bound to circular RNA BTBD7_hsa_circ_0000563 in coronary artery disease.

BACKGROUND: As a novel circRNA, BTBD7_hsa_circ_0000563 has not been fully investigated in coronary artery disease (CAD). Our aim is to reveal the possible functional role and regulatory pathway of BTBD7_hsa_circ_0000563 in CAD via exploring genes combined with BTBD7_hsa_circ_0000563. METHODS: A total of 45 peripheral blood mononuclear cell (PBMC) samples of CAD patients were enrolled. The ChIRP-RNAseq assay was performed to directly explore genes bound to BTBD7_hsa_circ_0000563. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were conducted to reveal possible functions of these genes. The interaction network was constructed by the STRING database and the Cytoscape software. The Cytoscape software were used again to identify clusters and hub genes of genes bound to BTBD7_hsa_circ_0000563. The target miRNAs of hub genes were predicted via online databases. RESULTS: In this study, a total of 221 mRNAs directly bound to BTBD7_hsa_circ_0000563 were identified in PBMCs of CAD patients via ChIRP-RNAseq. The functional enrichment analysis revealed that these mRNAs may participate in translation and necroptosis. Moreover, the interaction network showed that there may be a close relationship between these mRNAs. Eight clusters can be further subdivided from the interaction network. RPS3 and RPSA were identified as hub genes and hsa-miR-493-5p was predicted to be the target miRNA of RPS3. CONCLUSIONS: BTBD7_hsa_circ_0000563 and mRNAs directly bound to it may influence the initiation and progression of CAD, among which RPS3 and RPSA may be hub genes. These findings may provide innovative ideas for further research on CAD.

Comparison of ASSR and frequency specificity ABR induced by NB CE-Chirp for prediction of behavioral hearing thresholds in children with conductive hearing loss.

BACKGROUND: Electrophysiological tests are often used to evaluate hearing loss in infants and young children with conductive hearing loss, no matter to quantify or characterize. However, there are advantages and disadvantages associated with the various electrophysiological tests that are currently available. Therefore, there is no gold standard test. This study aimed to compare the value of narrow-band (NB) CE-Chirp-induced auditory steady-state response (ASSR) and auditory brainstem response (ABR) for assessing hearing thresholds in children with conductive hearing loss. We hope to identify an effective electrophysiological testing method to evaluate conductive hearing loss and provide a reference for clinical hearing assessment of infants with conductive hearing loss. SUBJECTS: and Methods: We selected 27 children (41 ears) aged 3-6 years with otitis media with effusion (OME). Within 1 day, they underwent behavioral audiometry and NB CE-Chirp-induced ASSR and ABR tests in sequence. Pearson's correlation analysis was performed to compare behavioral audiometry thresholds and ASSR and ABR response thresholds at 500, 1000, 2000, and 4000 Hz. RESULTS: The behavioral audiometry thresholds of all children were strongly correlated with the response thresholds of the two electrophysiological tests, with correlation coefficients of 0.659, 0.605, 0.723, and 0.857 for ASSR, and 0.587, 0.684, 0.753, and 0.802 for ABR. The proportion of children with a difference of ≤10 dB between ASSR and behavioral audiometry thresholds or between ABR and behavioral audiometry thresholds was not high, especially in the low frequencies. ABR results were superior to ASSR results in terms of predicting actual hearing levels. At 0.5, 1, 2, and 4 kHz, the average differences between the behavioral hearing thresholds and ASSR thresholds in the 41 ears were 5.6, 5.7, 2, and 5.6 dB, respectively. The average differences between behavioral hearing thresholds and ABR thresholds was -5.6, -1.4, -6.8, and 3.2 dB, respectively. The hearing loss configuration of the ASSR exhibited a peaked pattern, similar to behavioral audiometry, whereas the ABR exhibited an ascending pattern. The time to perform the single-ear ASSR test was 5.9 min, whereas the ABR test took 17.0 min. CONCLUSION: ASSR and ABR induced by the NB CE-Chirp correlated well with behavioral audiometry in children with conductive hearing loss. The NB CE-Chirp ASSR has advantages in terms of testing time and hearing configuration evaluation, whereas ABR has better reliability than ASSR. However, the stability of ASSR and ABR induced by the NB CE-Chirp is poor, and the thresholds obtained cannot replace behavioral audiometry in evaluating the true hearing of children with conductive hearing loss. However, ASSR and ABR can be used as auxiliary tests for cross-validation.

Correlation Analysis and Comparison of Adult CE-Chirp ABR Response Threshold and Pure Tone Hearing Threshold / 法医学杂志

Objective To study the application of CE-Chirp in the evaluation of hearing impairment in forensic medicine by testing the auditory brainstem response(ABR)in adults using CE-Chirp to ana-lyze the relationship between the V-wave response threshold of CE-Chirp ABR test and the pure tone hearing threshold.Methods Subjects(aged 20-77 with a total of 100 ears)who underwent CE-Chirp ABR test in Changzhou De'an Hospital from January 2018 to June 2019 were selected to obtain the V-wave response threshold,and pure tone air conduction hearing threshold tests were conducted at 0.5,1.0,2.0 and 4.0 kHz,respectively,to obtain pure tone listening threshold.The differences and statistical differences between the average pure tone hearing threshold and V-wave response threshold were compared in different hearing levels and different age groups.The correlation,differences and statistical differences between the two tests at each frequency were analyzed for all subjects.The lin-ear regression equation for estimating pure tone hearing threshold for all subjects CE-Chirp ABR V-wave response threshold was established,and the feasibility of the equation was tested.Results There was no statistical significance in the CE-Chirp ABR response threshold and pure tone hearing threshold dif-ference between different hearing level groups and different age groups(P>0.05).There was a good correlation between adult CE-Chirp ABR V-wave response threshold and pure tone hearing threshold with statistical significance(P<0.05),and linear regression analysis showed a significant linear correla-tion between the two(P<0.05).Conclusion The use of CE-Chirp ABR V-wave response threshold can be used to evaluate subjects'pure tone hearing threshold under certain conditions,and can be used as an audiological test method for forensic hearing impairment assessment.

Respuestas evocadas auditivas obtenidas mediante un estímulo chirp de banda ancha / Auditory evoked responses obtained by a broad-band chirp stimulus

Introducción: La estimación de la audición con Potenciales Evocados Auditivos de Tallo Cerebral obtenidos mediante estímulos tipo chirp constituye una alternativa de reciente aplicación. Varios autores han demostrado que, este tipo de estimulación compensa el retardo de la onda sonora en la codificación de frecuencias, generándose Potenciales Evocados Auditivos de Tallo Cerebral con componentes de amplitudes mayores. Objetivos: Diseñar y generar un estímulo chirp (banda ancha) para implementar en el sistema AUDIX (La Habana, Neuronic SA) y, realizar una serie de controles para evaluar su viabilidad en el registro de Potenciales Evocados Auditivos de Tallo Cerebral en sujetos con audición normal. Métodos: Las formulaciones que se utilizaron en la generación del estímulo fueron implementadas como una función en Matlab®, y luego, insertada en el sistema AUDIX con las siguientes especificaciones técnicas, frecuencia de muestreo: 48 kHz, composición de frecuencias (ascendente): 350-11300 Hz, y duración total: 4,95 ms. Se obtuvieron registros de PEATC mediante estímulos chirp y click a un nivel de intensidad fija (60 dB nHL) en 9 sujetos adultos (18 oídos) con audición normal. Resultados: El estímulo chirp diseñado tuvo un comportamiento funcional similar a lo reportado en la literatura. Cuando se compara con los Potenciales Evocados Auditivos de Tallo Cerebral -click, la onda V de Potenciales Evocados Auditivos de Tallo Cerebral -chirp mostró valores de amplitud significativamente mayores (relación de amplitud chirp/click: 1,62), con una ganancia promedio de 54 por ciento (p< 0,001, n= 18, prueba de rangos de Wilcoxon). Conclusiones: El estímulo chirp (banda ancha) diseñado resulta más eficiente que el estímulo click para obtener registros de Potenciales Evocados Auditivos de Tallo Cerebral. Con respecto a la amplitud de la onda V, el sistema muestra un funcionamiento lineal (mejor sincronía neural). Este tipo de estimulación pudiera resultar de mucha utilidad en programas de pesquisa auditiva neonatal pues la obtención de una onda V de mayor amplitud permitiría su fácil y rápida detección, y posible automatización(AU)

Introduction: Estimation of audition through brainstem auditory evoked potentials obtained by chirp stimuli is an alternative of recent application. It has been shown by several authors that this type of stimulation compensates for retardation of the sound wave in the coding of frequencies, generating auditory evoked responses with components of higher amplitudes. Objectives: Design and develop a broad-band chirp stimulus to be implemented in the AUDIX system and conduct a control series evaluation of its viability to register brainstem auditory evoked potentials in normal-hearing subjects. Methods: The formulations used to generate the stimulus were implemented as a function on Matlab® and then incorporated into the AUDIX system with the following technical specifications: sampling frequency: 48 kHz, frequency composition (rising): 350-11 300 Hz, and total duration: 4.95 ms. BAEP registries were obtained with chirp and click stimuli at a fixed intensity level (60 dB nHL) in nine normal-hearing adult subjects (18 ears). Results: The chirp stimulus designed had a functional behavior similar to the one reported in the literature. When compared with the click-BAEP, the V wave of chirp-BAEP displayed significantly higher amplitude values (chirp/click amplitude ratio: 1.62), with an average gain of 54 percent (p< 0.001, n= 18, Wilcoxon rank test). Conclusions: The broad band chirp stimulus designed proved to be more efficient than the click stimulus to obtain registries of Brainstem Auditory Evoked Potentials. Regarding V wave amplitude, the system was found to function linearly (better neural synchrony). This type of stimulation could be very useful in neonatal hearing screening programs, since a higher amplitude V wave could facilitate its fast and easy detection and possible automation(AU)

Combination of High Performance Liquid Chromatographywith Nano-electrospray ionization Chirp Z TransformIon Mobility Spectrometry / 分析化学

By combining frequency modulation Chirp Z transform ion mobility spectrometers (IMS) and multi nozzle electrospray array ionization source, a method of NanoESI-Chirp Z transform ion mobility spectrometry-high performance liquid chromatography was developed for the determination of n-alkyl ammonium bromide compounds.The parameters of NanoESI-Chirp Z transform IMS such as electric field intensity, solvent composition, and solution flow rate were investigated and optimized.Subsequently, four kinds of n-alkyl ammonium bromide compounds were respectively detected by this developed Chirp Z transform method and Fourier transform method, and the obtained results were compared.The result indicated that the optimum conditions were electric field intensity of 4.5 kV, and ESI solution flow rate of 8 μL/min.Then a test mixture containing tetrabutylammonium bromide, tetrapentylammoniumbromide, tetrahexylammonium bromide, tetraheptylammonium bromide, tetranoctylammoniumbromideandtetrakis(decyl) ammonium bromide was successfully separated and determined by the HPLC-nanoESI-Chirp Z IMS method.Chirp Z transform method provided higher signal to noise ratio compared to conventional signal averaging method, and was superior to FT method in the determination of drift time.

Relationship between Evoked Auditory Steady-state Responses and Pure Tone Audiometry in Children with Different Levels of Hearing Loss / 听力学及言语疾病杂志

Objective To study the clinical significance of Chirp-ASSR and the characteristics of hearing loss patients by ASSR(auditory steady-state responses) under Chirp stimulation.Methods A total of 136 hearing loss children (5～10 years old) with 272 ears were distributed into four groups based on 500 Hz,1 000 Hz,2 000 Hz and 4 000 Hz auditory threshold arithmetic average:20～dB HL,40～dB HL,60～dB HL,and≥80 dB HL groups.To compare the correlation of the PTA and Chirp-ASSR in different frequencies domain through SPSS statistics 19.0 software,the data were used T-test and Pearson analysis.Results ①The group(≥80 dB HL) achieved a statistically significant higher reaction threshold than pure tone threshold.②The correlation index γ'of PTA and Chirp-ASSR showed a decline along with the hearing loss increase;It increased along with the test frequency,there was a significant difference between 500 Hz and 4 000 Hz(P＜0.05).Conclusion Chirp-ASSR is a frequency-specific electrophysiological test method,it could reflect the truthful listening ability,especially in mild,moderate,and severe hearing loss children.

Comparación de las amplitudes y latencias de la onda V del potencial evocado auditivo de tronco cerebral obtenidas a través de estímulos clic y CE-Chirp® / Comparison of brainstem auditory evoked potential wave V amplitudes and latencies obtained through click and CE-Chirp® stimuli

Introducción: El potencial evocado auditivo de tronco cerebral (PEATC) se ha convertido en un procedimiento estándar dentro de la evaluación audiológica. Durante décadas, el estímulo más utilizado ha sido el clic, sin embargo, últimamente se ha propuesto la utilización de estímulos de frecuencia modulada (chirp) para obtener resultados más eficientes. Objetivo: Comparar las amplitudes y las latencias de la onda V del PEATC obtenidas a través de estímulos clic y CE-Chirp® a distintas intensidades. Material y método: Se realizó un estudio de tipo cuantitativo, no experimental, transversal y descriptivo en 17 sujetos a los que se evaluó con un PEATC utilizando estímulos clic y CE-Chirp®. Resultados: Se obtuvieron mayores amplitudes de onda Vpara estímulos CE-Chirp® que para clic, en todas las intensidades evaluadas (80, 60, 40,30 y 20 dBnHL). Se obtuvieron menores latencias en la onda Vpara estímulos CE-Chirp® solo a 80 y 60 dBnHL, mientras que en el resto de las intensidades se obtuvo menores latencias con estímulos clic. Conclusiones: Existen diferencias significativas entre las latencias y amplitudes de la onda V obtenidas con estímulos clic y CE-Chirp®. Mientras los estímulos CE-Chirp® aportan en rapidez en el examen y en la búsqueda del umbral electrofisiológico más preciso, los estímulos clic serían los adecuados al momento de realizar un estudio de topodiagnóstico.

Introduction: The auditory brainstem response (ABR) has become a standard procedure in the audiological evaluation. For decades the most widely used stimulus was the click, but recently the use of chirp stimulus has been proposed for obtain more efficient results. Aim: To compare the amplitudes and latencies of wave V of ABR obtained through click and CE-Chirp® stimuli at different intensities. Material and method: A quantitative, not experimental, transversal and descriptive study was conducted with 17 subjects who were evaluated with ABR using click and CE-Chirp® stimuli. Results: Wave V larger amplitudes were verified for stimulus CE-Chirp®, in all the evaluated intensities (80, 60, 40, 30 and 20 dBnHL). Shorter latencies of wave V were obtained for CE-Chirp® stimuli only at 80 and 60 dBnHL, while it was found that the remaining intensities showed lower latencies with click stimuli. Conclusions: There are significant differences between latencies and amplitudes of the wave V obtained with CE-Chirp® and click stimuli. While the CE-Chirp® stimuli provides faster results for most accurate electrophysiological threshold, click stimuli would be appropriate to conduct site of the lesion testing.

CIinicaI Features Comparison of Auditory Brainstem Response by Chirp and CIick StimuIi in NormaI Hearing ChiIdren / 听力学及言语疾病杂志

Objective To study the characteristics of auditory brainstem response by chirp and click stimuli in normal hearing children.Methods A total of 97 children (194 ears)with normal hearing were recruited,including 50 male (100 ears),and 47 female (94 ears).The CE-chirp and the click acoustic stimulation were used to,and the ABR waveforms and latencies were obtained.ResuIts The chirp-ABR Ⅰ wave recognition rate (36%)was significantly lower than that of click-ABR (100%).At 80 dB nHL,chirp-ABR V wave latency was shorter than click-ABR,the difference was statistically significant (P0.05).At 80 dB nHL,no statistical significance of two kinds of a-coustic stimulation of ABR V wave amplitude difference (P>0.05).At 50 dB nHL,chirp-ABR significantly in-creased than click-ABR V wave amplitude with statistically significant differences (P0.05 ).ConcIusion The chirp acoustic stimulation produced the larger response amplitude,and was faster,demonstrating the noticeable advantages to tes-ting children.