Auditory Brainstem Response Stimuli Research Articles

Diagnostic accuracy of CE Chirp

ObjectiveThere has been an increase in the use of the CE-Chirp stimulus in automated auditory brainstem response (AABR) equipment for neonatal hearing screening. The purpose of this study is to evaluate the diagnostic accuracy of the LS CE-Chirp-evoked auditory brainstem response (ABR) compared to the click-evoked ABR for the identification of different degrees and configurations of sensorineural (SNHL) hearing loss. Method49 ears with mild to moderate SNHL were assessed: 16 ears with rising SNHL and 33 ears with sloping high frequency SNHL. Behavioural pure tone thresholds were obtained at 125–8000 Hz and ABR thresholds were measured using the click and LS CE-Chirp stimuli respectively. Click- and LS CE-Chirp-evoked thresholds were compared with each other and with behavioural pure tone average at 500, 1000, 2000 Hz (PTA), high frequency average at 2000, 4000, 8000 Hz (HFA) and low frequency average at 250, 500, 1000 Hz (LFA). Diagnostic accuracy of the two ABR stimuli was also compared by using ROC curves. ResultsDifferences between click- and LS CE Chirp-evoked ABR, and behavioural thresholds were not statistically significant (p > 0.05). The highest significant correlations for ABR using clicks to behavioural thresholds was found at 2000 and 4000 Hz, whereas, the highest correlation for LS CE-Chirp ABRs to behavioural thresholds was found at 1000, 2000 and 4000 Hz (r > 0.7, p < 0.001). A very strong, positive correlation was found between both click (r = 0.805, p < 0.001) and LS CE-Chirp (r = 0.825, p < 0.001) and the behavioural PTA. LS CE-Chirp ABR thresholds were closer to mid and low frequency thresholds than the click ABR while the click-evoked thresholds were in closer proximity to HFA. Sensitivity and specificity and false negative rates were identical. Diagnostic accuracy of the LS CE-Chirp ABR was equal to or better than click for low (area under the curve (AUC) = 0.83), mid (AUC = 0.89) and high frequency hearing losses (AUC = 0.73). However, scatterplots indicated more frequent underestimation of behavioural pure tone thresholds at mid and high frequencies with the LS CE-Chirp than for the click ABR. ConclusionThe diagnostic accuracy of the LS CE Chirp-evoked ABR is equivalent or better than the click-evoked ABR. The importance of ongoing surveillance and consideration of ABR screening protocols is consequently emphasized.

Auditory brainstem response to chirp stimulus in children with moderate and severe sensorineural hearing loss

BackgroundClick auditory brainstem response (ABR), is abrupt and rapid onset, have broad spectrum nonfrequency-specific response. ABR needs good neural synchrony, the greater number of neurons that fire results in a larger response amplitude. The application of chirp stimuli aims to produce a synchronized response from a large portion of hair cells in the basilar membrane. The chirp was designed to produce simultaneous displacement maxima along the cochlear partition by compensating for frequency-dependent traveling-time differences.ObjectivesThe aim of this study was to correlate between pure-tone audiometry (PTA) threshold and click and chirp-ABR thresholds in children with moderate and severe sensory neural hearing loss.Patients and methodsThis study included two groups: control group (G1), which consisted of 30 children with normal peripheral hearing and study group (G2), which consisted of 60 children with moderately severe sensorineural hearing loss (SNHL).ResultsResults showed that significant correlation between chirp and behavioral PTA and between click and behavioral PTA in normal hearing and hearing-impaired children, except in severe steeping SNHL. In steeping SNHL, there was a reduced correlation between behavioral PTA and click ABR stimuli. In addition, there was a significant correlation between narrow band-chirp at 500, 1000, and 4000 Hz and behavioral PTA in normal hearing and sensory neural hearing loss in children, otherwise in severe steeping SNHL. In this category, there was a reduced the correlation between behavioral PTA and narrow band-chirp-ABR stimuli.

A Comparison of Commercially Available Auditory Brainstem Response Stimuli at a Neurodiagnostic Intensity Level.

iChirp-evoked auditory brainstem responses (ABRs) yield a larger wave V amplitude at low intensity levels than traditional broadband click stimuli, providing a reliable estimation of hearing sensitivity. However, advantages of iChirp stimulation at high intensity levels are unknown. We tested to see if high-intensity (i.e., 85 dBnHL) iChirp stimulation results in larger and more reliable ABR waveforms than click. Using the commercially available Intelligent Hearing System SmartEP platform, we recorded ABRs from 43 normal hearing young adults. We report that absolute peak latencies were more variable for iChirp and were ~3 ms longer: the latter of which is simply due to the temporal duration of the signal. Interpeak latencies were slightly shorter for iChirp and were most evident between waves I-V. Interestingly, click responses were easier to identify and peak-to-trough amplitudes for waves I, III and V were significantly larger than iChirp. These differences were not due to residual noise levels. We speculate that high intensity iChirp stimulation reduces neural synchrony and conclude that for retrocochlear evaluations, click stimuli should be used as the standard for ABR neurodiagnostic testing.

Auditory brainstem response to chirp stimulus in children with moderate and severe sensorineural hearing loss

Introduction Click auditory brainstem response (ABR) is abrupt, has a rapid onset, and has a broad spectrum nonfrequency-specific response. ABR needs good neural synchrony, i.e., the greater number of neurons that fire results in a larger response amplitude. Recently, it has been suggested that a chirp stimulus may produce a synchronous response from a large portion of basilar membrane. The chirp was designed to produce simultaneous displacement maxima along the cochlear partition by compensating for frequency-dependent traveling time differences. Material and methods In this study, we attempt to find a correlation between pure tone threshold (PTA) and each of the click and chirp ABR thresholds in children with moderate and severe sensory neural hearing loss (SNHL). Results and conclusions Results show that there is a significant correlation between chirp and behavioral PTA and between click and behavioral PTA in children with normal hearing and hearing impaired but not in those with severe steeping SNHL. In steeping SNHL, there was reduced correlation between behavioral PTA and click ABR stimuli. In addition, there was a significant correlation between narrow band-chirp at 500, 1000 Hz, and 4000 Hz and behavioral PTA in children with normal hearing loss and SNHL but not in those with severe steeping SNHL. In this category, there was a reduction in correlation between behavioral PTA and narrow band-chirp ABR stimuli.

Effects of noise exposure on young adults with normal audiograms I: Electrophysiology

Noise-induced cochlear synaptopathy has been demonstrated in numerous rodent studies. In these animal models, the disorder is characterized by a reduction in amplitude of wave I of the auditory brainstem response (ABR) to high-level stimuli, whereas the response at threshold is unaffected. The aim of the present study was to determine if this disorder is prevalent in young adult humans with normal audiometric hearing. One hundred and twenty six participants (75 females) aged 18–36 were tested. Participants had a wide range of lifetime noise exposures as estimated by a structured interview. Audiometric thresholds did not differ across noise exposures up to 8 kHz, although 16-kHz audiometric thresholds were elevated with increasing noise exposure for females but not for males. ABRs were measured in response to high-pass (1.5 kHz) filtered clicks of 80 and 100 dB peSPL. Frequency-following responses (FFRs) were measured to 80 dB SPL pure tones from 240 to 285 Hz, and to 80 dB SPL 4 kHz pure tones amplitude modulated at frequencies from 240 to 285 Hz (transposed tones). The bandwidth of the ABR stimuli and the carrier frequency of the transposed tones were chosen to target the 3–6 kHz characteristic frequency region which is usually associated with noise damage in humans. The results indicate no relation between noise exposure and the amplitude of the ABR. In particular, wave I of the ABR did not decrease with increasing noise exposure as predicted. ABR wave V latency increased with increasing noise exposure for the 80 dB peSPL click. High carrier-frequency (envelope) FFR signal-to-noise ratios decreased as a function of noise exposure in males but not females. However, these correlations were not significant after the effects of age were controlled. The results suggest either that noise-induced cochlear synaptopathy is not a significant problem in young, audiometrically normal adults, or that the ABR and FFR are relatively insensitive to this disorder in young humans, although it is possible that the effects become more pronounced with age.

Electrophysiological Measures of Auditory Processing in Patients with Multiple Sclerosis

Previous studies demonstrated that patients with multiple sclerosis (MS) experience more hearing loss than age-matched control subjects. Patients with MS also exhibit deficits processing auditory stimuli, including speech in a background of noise. These findings suggest that auditory deficits in the MS population can result from damage to central neural pathways in addition to peripheral hearing structures. To assess auditory processing functions in patients with MS, this study used auditory event-related potentials (AERPs)—specifically, the auditory brain stem response (ABR) and long-latency AERPs including the P300. AERPs recorded from 20 patients with MS were compared to AERPs from 20 healthy control subjects. When ABR stimuli (clicks) were presented monaurally, there were no significant differences between groups in component latencies or amplitudes for waves I through V. However, binaural presentation of the same stimuli elicited wave V ABR components significantly greater in amplitude for the control group compared with the MS group. Long-latency AERP results showed no significant differences between groups for N100 latency and amplitude or for P300 latency. P300 component amplitude was significantly greater for control subjects compared with patients with MS. It is probable that neural degeneration and impaired neural transmission within the MS group contributed to these AERP results. AERPs are useful tools that can be used to assess peripheral and central auditory functions as well as cognitive processing abilities in patients with MS. AERPs could be used to evaluate neural integrity, disease progression, and treatment efficacy in this population.

Noise levels required to mask stimuli used in auditory brainstem response testing

The levels of noise necessary to effectively mask the stimuli commonly used in auditory brainstem response (ABR) tests were determined. The relative masking level (RLM) of twenty normally-hearing volunteers was measured behaviourally using ipsilaterally presented unfiltered noise in the presence of ABR stimuli. The upper limit for RLM was found to be typically 30 dB above the stimulus level when the stimulus was calibrated in dBnHL to ISO 389-6 (2007) and the noise was measured in dBSPL. This value is recommended when calculating the level of noise necessary to prevent cross-hearing during ABR testing.SumarioSe determinaron los niveles de ruido necesarios para enmascarar efectivamente los estímulos comúnmente utilizados en las pruebas de respuestas auditivas del tallo cerebral (ABR). Se midió en forma conductual el nivel de enmascaramiento relativo (RLM) de veinte voluntarios con audición normal, usando ruido no filtrado presentado ipsilateralmente en presencia de estímulos para ABR. Se encontró que el límite superior del RLM típicamente era de 30 dB por encima de nivel del estímulo cuando el estímulo estaba calibrado en dB nHL para ISO 389-6 (2007) y el ruido era medido en dB SPL. Este valor es recomendado cuando se calcula el nivel de ruido necesario para prevenir audición cruzada durante la evaluación con ABR.