Tone-burst ABR Research Articles

Clinical Value of Auditory Steady State Response Versus Tone Burst ABR for Evaluation of Severe to Profound Hearing Loss in Children

Clinical Value of Auditory Steady State Response Versus Tone Burst ABR for Evaluation of Severe to Profound Hearing Loss in Children

Tone-burst elicited auditory brainstem responses in full-term and pre-term infants

Objective To investigate the reliability of tone-burst auditory brainstem response (TB-ABR) latencies and thresholds in pre-term and full-term infants. Design TB-ABRs to 500 Hz and 4000 Hz tone-burst stimuli were recorded at two-week intervals over the first six weeks of life in a group of full-term infants (40–46 weeks gestational age [GA]) and over ten weeks (36–46 weeks gestation) in a group of preterm infants. Linear mixed model analyses evaluated within-subject changes and the effects of the subject group, age at assessment, and stimulus frequency on ABR latency and threshold. Study sample Twenty-four infants participated. Nine were full-term (GA: 39–41 weeks) and fifteen were healthy pre-term (GA: 28–34 weeks) at birth. Results TB-ABR wave V latencies at 70 dBnHL decreased throughout the study (p < 0.001) in pre-term babies for both test frequencies by approximately 0.5 ms. There were, however, no group or GA (at birth) effects indicating that response latency normalized in these children by the due date. Similarly, TB-ABR threshold levels in the premature group were elevated (p = 0.001) by approximately 5 dB in pre-term evaluation but were equivalent to those of full-term participants in the post-term assessment period. Conclusions In healthy, pre-term infants, tone-burst ABR testing is reliable from 36 weeks gestation.

Effects of Implantation and Reimplantation of Cochlear Implant Electrodes in an In Vivo Animal Experimental Model (Macaca fascicularis).

The objectives of this study were to evaluate the effect of reimplanting a cochlear implant electrode in animal normal-hearing cochlea to propose measures that may prevent cochlear injury and, given its close phylogenetic proximity to humans, to evaluate the macaque as a model for electroacoustic stimulation. Simultaneous, bilateral surgical procedures in a group of 5 normal-hearing specimens (Macaca fascicularis) took place in a total of 10 ears. Periodic bilateral auditory testing (distortion product otoacoustic emissions and auditory brainstem evoked responses [ABR]) took place during a 6-month follow-up period. Subsequently, unilateral explantation and reimplantation was performed. Auditory follow-up continued up to 12 months, after which animals were sacrificed and both temporal bones extracted for histological analysis. Implantation and reimplantation surgeries were performed without complications in 9 of 10 cases. Full insertion depth was achieved at reimplantation in four of five ears. Auditory evaluation: Statistically significant differences between implanted and reimplanted were observed for the frequencies 2000 and 11,000 Hz, the remaining frequencies showed no differences for distortion product otoacoustic emission. Before the procedure, average thresholds with click-stimuli ABR of the five animals were 40 dB SPL (implanted group) and 40 dB SPL (reimplanted group). One week after first implantation, average thresholds were 55 dB SPL and 60 dB, respectively. After 12 months of follow-up, the average thresholds were 72.5 dB SPL (implanted group) and 65 dB SPL (reimplanted group). Hearing loss appeared during the first weeks after the first implantation and no deterioration was observed thereafter. Differences for ABR under click stimulus were not significant between the two ear groups. Similar results were observed with tone-burst ABR. A 15 dB shift was observed for the implanted group preoperatively versus 1-week post surgery and an additional 17.5 dB shift was seen after 12-month follow-up. For the reimplanted group, a 20 dB shift was observed within the first week post reimplantation surgery and an additional 5 dB after 6 months follow-up. Statistical analysis revealed significant differences between the implanted and reimplanted ear groups for frequencies 4000 Hz (p = 0.034), 12000 Hz (p = 0.031), and 16,000 Hz (p = 0.031). The histological analysis revealed that the electrode insertion was minimally traumatic for the cochlea, mainly indicating rupture of the basilar membrane in the transition area between the basal turn and the first cochlear turn only in Mf1 left ear. With application of minimally traumatic surgical techniques, it is possible to maintain high rates of hearing preservation after implantation and even after reimplantation. Partial impairment of auditory thresholds may occur during the first weeks after surgery, which remains stable. Considering the tonotopic distribution of the cochlea, we found a correlation between the histological lesions sites and the auditory findings, suggesting that a rupture of the basilar membrane may impact hearing levels. The macaque was observed to be a functionally and anatomically an excellent animal model for cochlear implantation.

Estimating audiometric thresholds using simultaneous acquisition of ASSR and ABR from QASSR in patients with sensorineural hearing loss

Objectives: To evaluate the accuracy with which the innovative QASSR method predicts behavioral thresholds in adult patients with sensorineural hearing loss. Design: Subjects were tested at four carrier frequencies (500, 1000, 2000, and 4000 Hz).The resulting QASSR recordings were analyzed for thresholds and magnitude/phase characteristics. Tone-burst ABR was recovered from QASSR signal using CLAD method and analyzed in the time domain. The electrophysiological estimates were compared to hearing thresholds determined behaviorally. Study sample: Sixteen ears of nine volunteer subjects recruited from a clinical population. Results: All mean threshold estimates differed less than 3 dB for QASSR and less than 5 dB for ABR at 1000, 2000 and 4000Hz (carrier or pure-tone test frequencies). The largest differences were observed for both at 500 Hz (5.63 and 11.56 dB respectively).The audiometric configurations of QASSR and ABR estimates followed those of the respective behaviorally determined configurations across ears tested. Conclusions: QASSR method merges two dissimilar stimulation techniques, transient and steady-state, to create a hybrid stimulation-and-analysis paradigm that seems to improve the overall performance of the electrophysiological threshold estimation. The unique feature of the QASSR technique is the additional information afforded by the transient ABR, recovered from the same recording. The QASSR thus holds promise to be a very useful tool for practical clinical applications.

Lessons from LOCHI.

Lessons from LOCHI.

Study on the relationship between tone burst ABR and CE-Chirp ASSR in infants with profound sensorineural hearing loss

To analyse the correlation between tone burst auditory brainstem response (tone burst auditory brainstem response, tb-ABR) and CE-Chirp voice evoked auditory steady-state response (auditory steady-state response, CE-Chirp ASSR) in infants with profound sensorineural hearing loss. A total of 45 infants with profound sensorineural hearing loss underwent threshold tone burst ABR and CE-Chirp ASSR of the frequency response test, response thresholds were recorded in 0.5, 1.0, 2.0 and 4.0 kHz. Whether there was correlation or not existed between two methods were analyzed, SPSS 11.0 statistics software was used. Tone burst ABR and CE-Chirp ASSR could lead to different degrees of threshold in each frequency. Response e elicited threshold percentage mainly concentrated in the 91-100 dBnHL, correlation coefficient between 500-4 000 Hz response threshold elicited rate were: 0.837, 0.913, 0.909, and 0.919, respectively (P < 0.001). The difference of the frequency response threshold test between CE-Chirp ASSR and tone burst ABR were not significant (P > 0.05, Chi square). The tone burst ABR and CE-Chirp ASSR each frequency have different levels of residual hearing in infants with profound sensorineural hearing loss diagnosed by Click ABR, good correlation exists between tone burst ABR and CE-Chirp ASSR.

Air and Bone Conduction Click and Tone-Burst Auditory Brainstem Thresholds Using Kalman Adaptive Processing in Nonsedated Normal-Hearing Infants.

To study normative thresholds and latencies for click and tone-burst auditory brainstem response (TB-ABR) for air and bone conduction in normal infants and those discharged from neonatal intensive care units, who passed newborn hearing screening and follow-up distortion product otoacoustic emission. An evoked potential system (Vivosonic Integrity) that incorporates Bluetooth electrical isolation and Kalman-weighted adaptive processing to improve signal to noise ratios was employed for this study. Results were compared with other published data. One hundred forty-five infants who passed two-stage hearing screening with transient-evoked otoacoustic emission or automated auditory brainstem response were assessed with clicks at 70 dB nHL and threshold TB-ABR. Tone bursts at frequencies between 500 and 4000 Hz were used for air and bone conduction auditory brainstem response testing using a specified staircase threshold search to establish threshold levels and wave V peak latencies. Median air conduction hearing thresholds using TB-ABR ranged from 0 to 20 dB nHL, depending on stimulus frequency. Median bone conduction thresholds were 10 dB nHL across all frequencies, and median air-bone gaps were 0 dB across all frequencies. There was no significant threshold difference between left and right ears and no significant relationship between thresholds and hearing loss risk factors, ethnicity, or gender. Older age was related to decreased latency for air conduction. Compared with previous studies, mean air conduction thresholds were found at slightly lower (better) levels, while bone conduction levels were better at 2000 Hz and higher at 500 Hz. Latency values were longer at 500 Hz than previous studies using other instrumentation. Sleep state did not affect air or bone conduction thresholds. This study demonstrated slightly better wave V thresholds for air conduction than previous infant studies. The differences found in the present study, while statistically significant, were within the test step size of 10 dB. This suggests that threshold responses obtained using the Kalman weighting software were within the range of other published studies using traditional signal averaging, given step-size limitations. Thresholds were not adversely affected by variable sleep states.

Accuracy of auditory steady state and auditory brainstem responses to detect the preventive effect of polyphenols on age-related hearing loss in Sprague-Dawley rats.

Aging causes histological, electrophysiological and molecular changes in the cochlea. The free radical theory of aging, has obtained consensus, and the mitochondrion is reported to play a key role in aging as a major source of reactive oxygen species. In the last years, there has been a significant increase in the interest in polyphenols because of the antioxidant properties and their role in the prevention of various diseases associated with oxidative stress, including aging. The aim of this study was to evaluate the preventive effect of different polyphenols on ARHL with auditory-evoked potentials. 100 Healthy female Sprague-Dawley (SD) rats were used for this study. Five groups were created based on the age of the rats, in months: 3, 6, 12, 18 and 24 months old. Two additional groups were created based on the treatment received. In the control group, 50 animals were assigned to no treatment. In the treated group, 50 animals were given a vehicle mixture of polyphenols for the half of the life before euthanization. Nine frequencies were tested (0.5-16 kHz) with ASSR and tone-burst ABR, performed on all of the rats prior to sacrifice. 100-μs auditory clicks ABRs were also recorded. A significant decrease in the audition was detected with ABR and ASSR in both treated and non-treated groups, as the different groups became older. This deterioration was more accurately measured at acute frequencies. Significantly lower thresholds were observed in the treated rats in the 6, 12 and 18-month-old group in the treated rats compared with the control group. All of the thresholds elicited using the ASSR technique were lower than the thresholds obtained using the ABR, regardless of the stimulus type. The present study demonstrated the benefits of the polyphenols, which generated a significant protection against ARHL, with significantly improved ASSR and tone-burst ABR auditory thresholds in rats receiving treatment with polyphenols.

Binaural interaction in the auditory brainstem response: A normative study

ObjectiveBinaural interaction can be investigated using auditory evoked potentials. A binaural interaction component can be derived from the auditory brainstem response (ABR–BIC) and is considered evidence for binaural interaction at the level of the brainstem. Although click ABR–BIC has been investigated thoroughly, data on 500Hz tone-burst (TB) ABR–BICs are scarce. In this study, characteristics of click and 500Hz TB ABR–BICs are described. Furthermore, reliability of both click and 500Hz TB ABR–BIC are investigated. MethodsEighteen normal hearing young adults (eight women, ten men) were included. ABRs were recorded in response to clicks and 500Hz TBs. ABR–BICs were derived by subtracting the binaural response from the sum of the monaural responses measured in opposite ears. ResultsGood inter-rater reliability is obtained for both click and 500Hz TB ABR–BICs. The most reliable peak in click ABR–BIC occurs at a mean latency of 6.06ms (SD 0.354ms). Reliable 500Hz TB ABR–BIC are obtained with a mean latency of 9.47ms (SD 0.678ms). Amplitudes are larger for 500Hz TB ABR–BIC than for clicks. ConclusionThe most reliable peak in click ABR–BIC occurs at the downslope of wave V. Five hundred Hertz TB ABR–BIC is characterized by a broad positivity occurring at the level of wave V. SignificanceThe ABR–BIC is a useful technique to investigate binaural interaction in certain populations. Examples are bilateral hearing aid users, bilateral cochlear implant users and bimodal listeners. The latter refers to the combination of unilateral cochlear implantation and contralateral residual hearing. The majority of these patients have residual hearing in the low frequencies. The current study suggests that 500Hz TB ABR–BIC may be a suitable technique to assess binaural interaction in this specific population of cochlear implant users.

Tone burst stimulus for auditory brainstem responses: Prediction of hearing threshold at 1kHz

To assess differences in hearing threshold estimation of four different ABR tone-bursts at 1kHz. Twenty-one (21) ears from 11 subjects were tested with pure-tone audiometry (PTA): 5 ears (24%) were normal hearing, 5 (24%) affected by mild hearing loss, 7 (33%) showed moderate hearing loss and 4 (19%) severe hearing loss. After PTA each subject underwent tone-burst ABR test at 1kHz using a linear gated (L_ABR) or Blackman windowed (B_ABR) stimuli with (nn_ABR) and without ipsilateral notched noise. Stimulation rate and filters settings were unchanged. Overall correlation between PTA and all ABRs thresholds was high, ranging from 0.84 to 0.94. In normal hearing ears none of the differences was significant, except for those measured with B_nn_ABR, which showed a mean 16dB overestimation of the pure-tone threshold (p<0.05). In mild hearing loss group none of the differences between thresholds were significant. In moderate and severe hearing loss groups significant differences were measured with L_nn_ABR (p<0.05) with a mean 7.5dB underestimation of PTA. Although very similar, some significant differences were found when considering specific group of patients with different degrees of hearing loss.

Furosemide Administered before Noise Exposure can Protect the Ear

We assessed the effect of furosemide administration on noise-induced hearing loss. This drug reversibly elevates the auditory threshold by inducing a temporary reduction of the endocochlear potential and thereby suppresses the cochlear amplifier and active cochlear mechanics. Mice were given a single injection of furosemide 30 minutes before exposure to 113 dB sound pressure level broadband noise. Control animals received saline solution. Furosemide was administered in other mice after the noise exposure. Auditory threshold shifts were assessed by recording auditory nerve brain stem evoked response (ABR) thresholds to broadband clicks. The mean ABR threshold in the group injected with furosemide and exposed to temporary threshold shift (TTS)-producing noise was elevated by 20.4 +/- 12.3 dB, and that in the saline control group was elevated by 35.4 +/- 18.3 dB (p < 0.02). The mean threshold elevations in the group injected with furosemide and exposed to permanent threshold shift (PTS)-producing noise and in the PTS saline control group were 15.0 +/- 10.3 dB and 27.0 +/- 12.7 dB, respectively (p < 0.01). Similar results were obtained when the PTS was assessed with an 8-kHz tone burst ABR. There was no significant difference in the PTS between mice given a single injection of furosemide and those given saline solution after the noise; this finding shows that furosemide is not acting as an antioxidant. It appears that reversible hearing threshold elevation as a result of furosemide administration before noise exposure can reduce the TTS and PTS. This finding provides insight into the mechanism of noise-induced hearing loss.

Tone-evoked brainstem responses and auditory steady state responses to 40hz and 80hz amplitude modulated stimuli with different frequencies — a comparative study

Tone burst evoked auditory brainstem responses and auditory steady state responses with 40 or > 80 Hz modulation can be used to determine frequency specific threshold. The present study was taken up to check for the efficacy of estimating hearing thresholds by tone burst ABR and ASSR. The frequency effect (low, mid and high) on estimating the threshold was also focused upon. 20 normal hearing adults (40 ears) in the age range of 16 to 30 years participated in the study. The pure tone audiometry and immittance was initially done. Subsequently, tone-burst ABR, 80Hz ASSR and 40Hz ASSR to estimate the threshold with three frequencies 500Hz (low), 2000Hz (mid) and 4000Hz (high) was done. The data was analyzed statistically using pair sample t-test. ASSR threshold for 80Hz and 40Hz was almost comparable. ASSR was superior to estimate the threshold than tone-burst ABR. For the low frequency the discrepancy between the behavioral threshold and frequency-specific evoked audiometry was more when compared to mid and high frequency. Present study showed that steady-state responses were efficient means of threshold detection than visual detection of ABR wave-V. In awake adult subjects, 40Hz and 80Hz amplitude modulated produced similar results. For the threshold estimation ASSR was better than tone-burst ABR.

Frequency-specific objective audiometry: Tone-evoked brainstem responses and steady-state responses to 40 Hz and 90 Hz amplitude modulated stimuli

Tone-evoked Auditory Brainstem Responses (tone-burst ABRs) and Auditory Steady-State Responses (ASSRs) with 40 or 90 Hz amplitude modulation (AM) were compared, using the same equipment and recording parameters, to determine which of these three methods most accurately approached the behavioural hearing thresholds in response to 500 Hz and 2000 Hz stimuli in eleven awake adults with normal hearing.Estimates of the thresholds obtained with the three methods were 10, 18, and 26 dB SL at 500 Hz; and 10, 12, and 22 dB SL at 2000 Hz; using 40 Hz ASSR, 90 Hz ASSR, and tone-burst ABR, respectively. ASSRs with 40 Hz AM stimuli produced significantly better results (lowest thresholds with SD = 0), whereas the wave-V analysis on the tone-burst ABR produced the poorest results. In the averaged ABRs, a robust steady-state potential was also visible. Analysis of those steady-state responses showed estimated thresholds of 13 and 14 dB SL (at 500 and 2000 Hz, respectively), thus considerably better than the estimated thresholds from the wave-V analysis.It is concluded that the 40 Hz ASSR showed superior results, especially at 500 Hz.SumarioUtilizando el mismo equipo y los mismos parámetros de prueba, se compararon las respuestas auditivas de tallo cerebral evocadas por tonos ABR de burst tonales y las respuestas auditivas de estado estable (ASSR) con 40 o 90 Hz de modulación de amplitud (AM), para determinar cual de estos tres métodos se aproximaba con mayor exactitud a los umbrales auditivos comportamentales en 500 y 2000 Hz, en 11 adultos normoyentes despiertos.La estimación de los umbrales obtenidos con los tres métodos fueron 10, 18 y 26 dBSL a 500 Hz y 10, 12 y 22 dBSL a 2000 Hz con 40 Hz ASSR, 90 Hz ASSR y ABR de pips tonales, respectivamente. Las ASSR con estímulo de 40 Hz AM produjeron resultados significativamente mejores (umbral menor con SD = 0), mientras que el análisis de la onda V en los ABR con burst tonales generó los resultados más pobres. En los ABR promediados, se pudo observar un potencial de estado estable robusto. El análisis de las respuestas de estado estable mostró umbrales estimados de 13 y 14 dBSL (500 y 2000 Hz, respectivamente), que son considerablemente mejores que los umbrales del análisis de la onda V. Se concluye que las ASSR de 40 Hz muestran resultados superiores, especialmente a 500 Hz.

Diagnosis and Follow-up of Hearing Loss in Infants

Diagnosis and Follow-up of Hearing Loss in Infants

Predicting Pure-Tone Thresholds with Dichotic Multiple Frequency Auditory Steady State Responses

The accuracy of dichotic multiple frequency auditory steady state in predicting pure-tone thresholds at 0.5, 1, 2, and 4.0 kHz compared to an ABR protocol (click and tone burst at 0.5 kHz) were explored in a group of 25 hearing-impaired subjects across the degree and configuration spectrum. Mean steady state thresholds were within 14, 18, 15, and 14 dB of the pure tones at 0.5, 1, 2, and 4 kHz, compared to the tone-burst ABR at 0.5 kHz pure-tone difference of 24 dB, and a click-evoked pure-tone (2-4 kHz) difference of 9 dB. Recording time for the steady state protocol was 28 minutes (+/- 11) compared to 24 minutes (+/- 9) of the ABR protocol. Degree of loss had a significant effect on steady state; configuration of hearing loss had a limited effect. Mf ASSR predicted thresholds with relative accuracy although some configurations showed discrepancies for low-frequency estimates.

ABR thresholds to tonebursts gated with Blackman and linear windows in adults with high-frequency sensorineural hearing loss.

The goal of this study was to determine whether tonebursts gated on and off using a nonlinear, exact-Blackman-gating function would be a more frequency-specific stimulus for auditory brain stem response audiometry than the more traditional 2-1-2 cycle linearly gated toneburst. Toneburst ABRs were recorded in 10 adults with normal hearing and in 18 adults with sloping high-frequency sensorineural hearing loss. It was hypothesized that any advantage of the Blackman stimuli for frequency-specific threshold assessment should be evident in hearing-impaired subjects with hearing loss confined to the 2000 to 4000 Hz frequency region since spectral splatter in the toneburst stimuli could lead to an underestimation of hearing loss based on the ABR thresholds. ABR stimuli consisted of 2000- and 4000-Hz 2-1-2 (rise-plateau-fall) cycle linearly gated tonebursts and 1-0-1 msec exact-Blackman-gated tonebursts. An additional 0.5-0-0.5 msec 4000-Hz Blackman-gated toneburst was used to investigate whether the difference in rise/fall characteristics of the linearly and Blackman-gated tonebursts could account for any differences in ABR results at 4000 Hz. The ABR toneburst stimuli were calibrated behaviorally in 15 adults with normal hearing. In the normal-hearing listeners toneburst-ABR thresholds generally exceeded behavioral thresholds by 10 to 13 dB for all stimuli. Correlations of 0.85 to 0.96 were obtained between 2000 and 4000 Hz toneburst ABR thresholds and pure-tone audiometric thresholds in the hearing-impaired listeners. Results were similar for Blackman- and linearly gated stimuli. There were no clear differences between Blackman- and linearly gated tonebursts in terms of how well ABR thresholds predicted pure-tone thresholds at 2000 and 4000 Hz. In general audiometric thresholds were predicted with good accuracy (+/-15 dB) by the toneburst ABR thresholds. The 4000-Hz audiometric threshold was underestimated in one subject with a very steeply sloping hearing loss by both Blackman- and linearly gated toneburst ABR thresholds, indicating that ipsilateral masking such as notched noise would be needed to ensure frequency specificity in this and similar cases.

Partial labyrinthectomy with hearing preservation: Frequency-specific data using tone-burst ABR

Partial labyrinthectomy with hearing preservation: Frequency-specific data using tone-burst ABR