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The relationship between auditory brainstem response latencies and behavioral thresholds in normal hearing infants and adults.

The relationship between behavioral thresholds and auditory brainstem response (ABR) latencies for 4 and 8 kHz tone pips were examined in normal-hearing 3-month-olds, 6-month-olds and adults. The latencies of waves I and V and the I-V interval of the ABR were analyzed. A linear latency-intensity function was also fit to each subject's latencies for each wave at several levels. The y-intercept of the latency-intensity function was used as a summary measure of latency to examine behavior-ABR correlations. The pattern of age-related change in behavioral threshold was not closely matched by age-related latency reduction for Wave I, Wave V or the I-V interval. However, 3-month-olds with higher behavioral thresholds had longer Wave V latencies and longer I-V intervals than 3-month-olds with lower behavioral thresholds. There was no significant difference in latency between 6-month-olds or adults with higher thresholds and 6-month-olds or adults with lower thresholds. There was also a significant correlation between the Wave V-Wave I latency-intensity intercept difference and behavioral threshold at both 4 and 8 kHz among 3-month-olds. The correlation was not significant among 6-month-olds or adults. These findings suggest that one of the factors responsible for immature behavioral thresholds at 3 months is related to transmission through the auditory brainstem. Because variability in hearing threshold among normal-hearing adults is low, it is not surprising that behavioral threshold is unrelated to ABR latency in this group. However, the lack of such a relationship among 6-month-olds implies that structures central to the auditory brainstem, either sensory or nonsensory, or both, must be responsible for immature behavioral thresholds after 6 months of age.

Acoustic Stimulation↗

Low-frequency specificity of the auditory brainstem response threshold elicited by clicks masked with 1590-Hz high-pass noise in subjects with sloping cochlear hearing losses.

In this study, the frequency specificity of the ABR threshold to stimulation with a click masked with 1590-Hz high-pass noise was determined in subjects with sloping cochlear hearing losses both high- and low-frequency in character. The results show that the ABR threshold elicited by this stimulus is low-frequency specific. The standard error in estimating the 1,000-Hz pure-tone threshold from the high-pass-noise-masked click-evoked ABR threshold is 10.2 dB which equals that for estimating the 3,000-Hz pure-tone threshold from the routinely used unmasked click ABR threshold. The ABR threshold elicited by a click masked with 1590-Hz high-pass noise can therefore be regarded as an accurate tool to predict the pure-tone hearing loss at 1,000 Hz. However, this method is less suitable for routine clinical testing because of the masking noise needed: the occasional high loudness level adversely affects the response quality and reduces the dynamic range of pure-tone hearing losses to be assessed. A third disadvantage is that determining the masking level electrophysiologically for each ear is time consuming. The search for a method with no or less masking noise should therefore continue.

Acoustic Stimulation↗

Monaural versus binaural auditory brainstem response threshold to clicks masked by high-pass noise in normal-hearing subjects.

Monaural and binaural auditory brainstem response (ABR) thresholds to clicks masked by high-pass noise with a cut-off frequency of 1,590 Hz were measured in normal-hearing subjects. In sleeping normal-hearing subjects, the 1,000-Hz frequency-specific ABR threshold for binaural stimulation amounted to 12 dB nHL and for monaural stimulation to 18 dB nHL. No significant difference in latency was found between monaural and binaural stimulation. Binaural ABR threshold was 5.5 +/- 1.4 dB (mean +/- SEM) lower than the mean monaural ABR threshold. This difference is statistically significant (Student's t test; p less than 0.005).

Acoustic Stimulation↗

[Evaluation of hearing thresholds of 40Hz auditory event related potential and auditory brainstem response].

Recordings of pure tone response, 40 Hz auditory event-related potential (40 Hz AERP) and auditory brainstem response (ABR) were obtained for 74 ears of 42 cases (32 normal ears, 42 injured ears). 40 Hz AERP (0.5-2 kHz) of 20 ears was tested under natural sleep and awake conditions. The results showed that the threshold of 40 Hz AERP was higher than that of tone pip, with the difference of 12.7 +/- 6.4 dBnHL at 0.5 kHz, 14.7 +/- 6.3 dBnHL at 1 kHz, and 15.6 +/- 5.6 dBnHL at 2 kHz respectively. The threshold of 40 Hz AERP increased in natural sleep compared with that in awake state. The threshold of ABR was higher than the behavioral. The data suggests that jointly using several tests get more accurate and objective results in evaluating hearing loss.

Adolescent↗

[The development of hearing sensitivity in altricial birds: the absolute thresholds of the generation of evoked potentials].

Thresholds of field L auditory evoked potentials EP were studied in 1.5-9-day-old nestlings of pied flycatcher in response to pure tone signals of different frequencies. According to the tendencies of age dynamics of auditory EP thresholds (2-9 days of life) all hearing range was divided into three separate channels: low-frequency (0.3-1.0 kHz), intermediate-(1.5-4.0 kHz) and high-frequency (5.0-8.0 kHz) ones. The widening of the hearing range in its high-frequency part was demonstrated on days 4-5 of life. The development of auditory sensitivity was shown to continue within all three channels in postembryonic period (days 2-9 post-hatching), each of the channels being characterized by its own age dynamics of auditory EP thresholds. Reproduction of tape-recorded species song during days 1-3 post-hatching resulted in significant decrease of auditory EP thresholds.

Acoustic Stimulation↗

Electrodermally differentiated subgroups of anxiety patients and controls. II: Relationships with auditory, somatosensory and pain thresholds, agoraphobic fear, depression and cerebral laterality.

Patients diagnosed (DSM III) with anxiety disorders (agoraphobia, panic syndrome, generalised anxiety syndrome) were classified along with controls as electrodermally stabile or labile on the basis of non-specific electrodermal activity and rate of habituation to tones. While patients showed more evidence of psychopathology than controls on scales of anxiety, neuroticism, depression and agoraphobic fear, patient labiles scored higher than stabiles on agoraphobic fear and were differentiated by higher scores of Beck depression. They were also more sensitive to pain, whereas patient stabiles were less sensitive at absolute somatosensory threshold. Amongst controls agoraphobic fear was associated with lability and stabiles scored higher on autonomy in locus of control. Lateral asymmetries in auditory thresholds were consistent with reciprocal hemispheric influences on electrodermal reactivity and habituation, modifiable by anxiety. Interrelationships between fear, depression, sensitivity to somatosensory stimulation, pain, and superior vigilance performance in patient labiles were consistent with elevated right hemisphere function.

Agoraphobia↗

Comparison between the frequency specificities of auditory brainstem response thresholds to clicks with and without high-pass masking noise.

In this study, the frequency specificity of the auditory brainstem response (ABR) threshold to a click masked with 1590-Hz high-pass masking noise is compared with the frequency specificity of the unmasked click-evoked ABR threshold. The ABR threshold to the high-pass-noise-masked click stimulus is low frequency specific and corresponds with the 1,000-Hz pure-tone threshold. Although the ABR threshold to the unmasked click stimulus corresponds with the '3,000'-Hz pure-tone threshold, the frequency specificity seems much less pronounced than that of the low-frequency-specific stimulus. This study shows, however, that this apparent lack of frequency specificity can be attributed to the selection of pure-tone hearing losses. The ABR threshold evoked by an unmasked click stimulus is, therefore, preeminently useful as a high-frequency point of a two-point audiogram. The possible reasons why the ABR threshold evoked by a broad-band stimulus as the unmasked click corresponds with the higher frequencies of the pure-tone audiogram are discussed.

Acoustic Stimulation↗

Comparison of electrically evoked whole-nerve action potential and electrically evoked auditory brainstem response thresholds in nucleus CI24R cochlear implant recipients.

In this study, differences between electrically evoked whole-nerve action potential (EAP) and electrically evoked auditory brainstem response (EABR) measurements within Nucleus CI24R cochlear implant recipients were evaluated. Precurved modiolus-hugging internal electrode arrays, such as the CI24R, are designed to provide more direct stimulation of neural elements of the modiolus. If the electrode array is closer to the modiolus, electrically evoked and behavioral levels might be lower than were previously recorded for the straight electrode array, the CI24M. EAP and EABR growth functions and behavioral levels were obtained for 10 postlingually deafened adults. Results revealed no significant differences between EAP and EABR threshold levels, and these levels were not significantly lower than those obtained using the CI24M.

Acoustic Stimulation↗

Threshold prediction using the auditory steady-state response and the tone burst auditory brain stem response: a within-subject comparison.

OBJECTIVE: The purpose of this study was to evaluate the accuracy with which auditory steady-state response (ASSR) and tone burst auditory brain stem response (ABR) thresholds predict behavioral thresholds, using a within-subjects design. Because the spectra of the stimuli used to evoke the ABR and the ASSR differ, it was hypothesized that the predictive accuracy also would differ, particularly in subjects with steeply sloping hearing losses. DESIGN: ASSR and ABR thresholds were recorded in a group of 14 adults with normal hearing, 10 adults with flat, sensorineural hearing losses, and 10 adults with steeply sloping, high-frequency, sensorineural hearing losses. Evoked-potential thresholds were recorded at 1, 1.5, and 2 kHz and were compared with behavioral, pure-tone thresholds. The predictive accuracy of two ABR protocols was evaluated: Blackman-gated tone bursts and linear-gated tone bursts presented in a background of notched noise. Two ASSR stimulation protocols also were evaluated: 100% amplitude-modulated (AM) sinusoids and 100% AM plus 25% frequency-modulated (FM) sinusoids. RESULTS: The results suggested there was no difference in the accuracy with which either ABR protocol predicted behavioral threshold, nor was there any difference in the predictive accuracy of the two ASSR protocols. On average, ABR thresholds were recorded 3 dB closer to behavioral threshold than ASSR thresholds. However, in the subjects with the most steeply sloping hearing losses, ABR thresholds were recorded as much as 25 dB below behavioral threshold, whereas ASSR thresholds were never recorded more than 5 dB below behavioral threshold, which may reflect more spread of excitation for the ABR than for the ASSR. In contrast, the ASSR overestimated behavioral threshold in two subjects with normal hearing, where the ABR provided a more accurate prediction of behavioral threshold. CONCLUSIONS: Both the ABR and the ASSR provided reasonably accurate predictions of behavioral threshold across the three subject groups. There was no evidence that the predictive accuracy of the ABR evoked using Blackman-gated tone bursts differed from the predictive accuracy observed when linear-gated tone bursts were presented in conjunction with notched noise. Similarly, there was no evidence that the predictive accuracy of the AM ASSR differed from the AM/FM ASSR. In general, ABR thresholds were recorded at levels closer to behavioral threshold than the ASSR. For certain individuals with steeply sloping hearing losses, the ASSR may be a more accurate predictor of behavioral thresholds; however, the ABR may be a more appropriate choice when predicting behavioral thresholds in a population where the incidence of normal hearing is expected to be high.

Acoustic Stimulation↗

[Objective auditory brainstem response threshold deficits in patients with cerebellopontine angle tumors].

The established criteria of auditory brainstem responses (ABR) such as JV latency, JI-V interpeak latency and interaural differences of latency or amplitude have been found to be sensitive for detecting tumors of the cerebellopontine angle if a response is present. However, the ABR can be absent in cases of acoustic neuromas because of desynchronization, even though pure-one audiometry indicates that responses should be present. This retrospective study compared the ABR and pure-tone thresholds in 234 cases with cerebellopontine angle tumors and a control group of 181 cases with sensory hearing losses in order to quantify threshold discrepancies. The average deficit of the objective ABR threshold (DOABRT) to the subjective pure-tone threshold for those frequencies between 1-6 kHz was 3.6 dB for the control group (ABR and pure tone thresholds very close) and 31.2 dB for the tumor group (ABR threshold much higher than the pure-tone threshold). ABR thresholds 30 dB higher than the high-frequency pure tone thresholds were found in 40.6% of the tumor group and in none of the control group. Thus, deficits of the ABR threshold >30 dB can be considered to be an additional criterion for detecting retrocochlear disease and increases ABR sensitivity for tumor detection even if responses are absent.

Adolescent↗

Computer-aided hearing threshold determination from cortical auditory evoked potentials.

The determination of the hearing threshold from cortical electric responses is usually based on the visual inspection of the recordings by an experienced evaluator. At least two factors are responsible for the limited reliability of such a procedure: first, visual inspection yields the response threshold and not the hearing threshold; and second, the result of a visual evaluation depends on subjective appraisal, which may be influenced by irrational factors. An approach of computer-aided evaluation is presented which simulates the visual inspection in that several typical features of the curves are judged numerically. The result of the classification is a single parameter, Q, whose value increases with better (subjective) perceptibility of the evoked potentials. A statistical analysis explores the relationship between the value of Q and the psychophysical hearing threshold. The results show that a prediction of hearing threshold with an accuracy of +/- 10 dB is possible.

Acoustic Stimulation↗

Variability in genetically induced age-related impairment of auditory brainstem response thresholds.

In genetically induced hearing impairment or deafness, the recessive mode of inheritance is by far the most common, but it has seldom been feasible to document audiological aberrations. In this study, auditory brainstem response (ABR) thresholds were analysed in groups of 10 heterozygote jerker (je/+) mice each, at ages of 3, 6 and 9 months in the frequency range 2-31.5 kHz. The animals were thereafter regularly tested up to a final age of 12 months. Forty age-related CBA/CBA mice were used as controls. The individual ABR thresholds in 3-, 6-, 9- and 12-month-old CBA/CBA mice were very similar, as also were those in 3- and 6-month-old je/+ mice (mean values within the normal range). In contrast, at 9 months--and even more so at 12 months--all je/+ animals showed large individual variations, with ABR thresholds varying randomly from near-normal to profound impairment. The wide individual spread of ABR thresholds in old je/+ animals was interpreted as reflecting the expression of a random influence of recessive jerker vis-à-vis the wild type of gene.

Aging↗

Response threshold determination of the brain stem auditory evoked response: a comparison of the phase versus magnitude derived from the fast Fourier transform.

An ensemble of 10 groups of brain stem evoked responses (BAERs), each consisting of 200 sweeps, was collected for different intensity levels and for a no-stimulus condition. A fast Fourier transform was calculated for the separate groups, which permitted a phase variance to be derived. The phase variance was compared to the magnitude value for selected frequency components making up the BAER. It was found that the phase variance was a better predictor of signal than magnitude. The superiority of prediction by phase results from intersubject variation being smaller for phase compared to magnitude.

Acoustic Stimulation↗

Prenatal exposure to cigarette smoking is associated with a decrease in arousal in infants.

OBJECTIVE: Sudden infant death syndrome has been related to both exposure to prenatal cigarette smoke and impaired arousability from sleep. We evaluated whether healthy infants born to mothers who smoked during pregnancy had higher auditory arousal thresholds than those born to mothers who did not smoke and whether the effects of smoking occurred before birth. STUDY DESIGN: Twenty-six newborns were studied with polygraphic recordings for 1 night: 13 were born to mothers who did not smoke, and 13 were born to mothers who smoked (>9 cigarettes per day). Other infants with a median postnatal age of 12 weeks were also studied, 21 born to nonsmoking mothers and 21 born to smoking mothers. White noise of increasing intensity was administered during rapid eye movement sleep to evaluate arousal and awakening thresholds. RESULTS: More intense auditory stimuli were needed to induce arousals in newborns (P =.002) and infants (P =. 044) of smokers than in infants of nonsmokers. Behavioral awakening occurred significantly less frequently in the newborns of smokers (P =.002) than of nonsmokers. CONCLUSIONS: Newborns and infants born to smoking mothers had higher arousal thresholds to auditory challenges than those born to nonsmoking mothers. The impact of exposure to cigarette smoke occurred before birth.

Arousal↗

[Evaluation of the effect of auditory fatigue on the human ear by auditory brain stem responses (ABR). I. Effect of auditory fatigue on temporary threshold shifts of ABR].

The effects of auditory fatigue on auditory brainstem responses (ABR) were investigated in 23 normal-hearing subjects. ABR was recorded before and after exposure to fatiguing noise. Behaviourally, the auditory fatigue was tested using a temporary threshold shifts (TTS) paradigm. The latency of waves I, III, V and interwave intervals I-III, III-V, I-V were analysed as functions of stimulus intensity. In post-exposure recordings a threshold elevation, significant increase of all waves latency, increase of interwave-interval III-V at 40,50,60 dB nHL and unaltered intervals I-III, I-V were observed.

Adult↗

Interlaminar differences of spike activation threshold in the auditory cortex of the rat.

The neural circuits of the auditory cortex are a substrate for the dual purpose of representing and storing the auditory signal on one hand, and sending its relevant features to other cortical and subcortical areas on the other hand. The ability to process and transform the signal crucially depends on achievement of the neuronal spike threshold following spatiotemporal summation of the synaptic signals. We used patch-clamp recording in a thin slice preparation to compare neuronal responses to current injection of layer II/III and layer V neurons. We found that while the two classes of neurons do not differ in passive neuronal properties, layer II/III neurons possess a lower firing threshold relative to layer V neurons (-44.8 +/- 2.4 mV vs. -34.3 +/- 4.0 mV). We speculate that a lower spiking threshold in layer II/III neurons might favor local intracolumnar activation for representation and storage of the auditory information whereas a more positive spiking threshold for layer V neurons may prevent unnecessary cortical spread of a scarcely processed signal.

Action Potentials↗

The effect of auditory feedback on phonation threshold pressure measurement.

The effect of auditory feedback on phonation threshold pressure (Pth) measurement was investigated in 14 females with normal, untrained voices. Two measurement systems (Glottal Enterprises MS 100--circumferentially vented mask and Kay Elemetrics Aerophone II--non-circumferentially vented mask) were examined under three conditions: (1) masked, (2) no mask, and (3) masked with enhanced auditory feedback-acoustic signal placed at ears through headphones. Masked with enhanced auditory feedback, in addition to subject training, significantly lowered Pth values regardless of mask design. The amount of auditory feedback provided by different mask designs was investigated and revealed a significant difference. Clinical significance of different auditory feedback levels provided by the two mask designs was investigated. Direct comparison of the mean values between systems was not possible because of each system's design and calibration. Comparisons were accomplished by subtracting means of select-paired conditions (masked/no mask; masked/masked plus masked with enhanced auditory feedback) within each system and then comparing these difference scores from the same paired conditions between each system. No clinical significance in difference scores was revealed because of varying amounts of auditory feedback provided by the masks. Results support the use of enhanced auditory feedback, in addition to subject training, when measuring Pth.

Adult↗