PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Auditory Threshold”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources
PubMed2005

[Universal hearing screening in newborns -- recommendations for organizing and conducting universal hearing screening for congenital hearing loss in Germany].

The Interdisciplinary Consensus Conference for Newborn Hearing Screening (IKKNHS) has worked out joint recommendations for universal hearing screening of newborns. In the consensus paper, 11 professional associations and scientific societies in the fields of gynecology and obstetrics, ENT, pediatrics, and phoniatrics and pedaudiology came to an agreement how to implement newborn hearing screening in Germany. The paper deals with the following topics: goals of universal newborn hearing screening, target group of hearing screening, schedule for screening, personnel involved in the screening program, technologies and framework conditions of hearing screening, documentation, continuous quality control of screening, confirmation diagnostics for conspicuous test subjects, motivation to take part in screening, information on newborn hearing screening, tracking, various infrastructural situations in urban and rural regions, follow-up care, in-patient vs. out-patient screening, cost factors of screening, reporting children with permanent hearing loss to the German Central Registry for hearing loss in children.

Animals↗
PubMed1994

[Clinical presentation and diagnosis of small acoustic neurinomas].

With the invention of magnetic resonance imaging (MRI) and the auditory evoked brain stem responses (AEBR), it has become possible to diagnose acoustic tumours while they are still small. As a result, it has become obvious that the clinical presentation of smaller lesions can be some-what different from what is considered typical of an acoustic neuroma. Likewise, whereas the sensitivity of auditory brain stem responses for larger tumours is good, the sensitivity for smaller tumours has recently been in doubt, particularly if the patient presents early in the course of the disease with only mild otologic complaints. A retrospective study of patients treated for small acoustic neuromas, defined as less than 1 cm extension into the cerebellopontine angle, was conducted to assess ABR results as well as the clinical and audiological presentation in these patients. Of the 70 patients included in the study, auditory brain stem responses were abnormal in 65 (93%), based on wave V latency prolongation and intra-aural latency differences. These would indicate that auditory brain stem responses are a valid screening test for acoustic neuromas, even in the early stages of development. The clinical presentation of patients with small acoustic tumours was similar to the presentation reported for acoustic neuromas in general, but with vertigo occurring more often in patients with smaller tumours. Several atypical patterns of hearing loss were seen in this population.

Adult↗
PubMed2005

Brainstem auditory-evoked responses in full-term newborn infants with temporary low Apgar score.

CONCLUSIONS: No abnormalities, with the exception of maturational changes, in BAER were found during the neonatal period. The results suggest that a temporary low Apgar score is not accompanied by any significant auditory impairment. OBJECTIVE: To examine brainstem auditory function in newborn infants with a temporary low Apgar score but no clinical signs of hypoxic-ischaemic encephalopathy (HIE). MATERIAL AND METHODS: The subjects were 36 full-term infants with Apgar scores of < or =7 at 1 and/or 5 min and > or =8 at 10 min but without HIE. The brainstem auditory-evoked response (BAER) was serially recorded at click rates of 21, 51 and 91/s on Days 1, 3, 5, 7 and 30 after birth. RESULTS: On Day 1 and Days 3-5, the latencies of waves I, III and V tended to increase slightly at all click rates but did not differ significantly from normal control values. Thereafter, all latencies tended to decrease, reaching control values on Day 30. The I-V interval was similar to the control values at all click rates during the first 5 days, tended to decrease from Day 7 and did not differ from the control values on Day 30. There were no significant changes in BAER wave amplitudes at any of the click rates on any day.

Apgar Score↗
PubMed2001

The importance of pre-analysis windowing on auditory brainstem response fast Fourier transform analysis.

Analysis of auditory brainstem response (ABR) frequency content using fast Fourier transform (FFT) analysis has been used to improve ABR sensitivity and specificity as a diagnostic/site of lesion assessment tool, to improve our understanding of ABR components, and to guide ABR stimulus and recording parameter settings. Threatening this success, however, is the literature's poor control of pre-FFT windowing of the ABR prior to ABR FFT analysis. This study examined the significance of using no (NW), vs Blackman (BW), vs modified Blackman (MBW) pre-FFT windows on the FFT analysis of ABRs recorded from normal subjects. Pre-FFT windowing was shown to significantly reduce (p < 0.00005) ABR FFT magnitudes, but not frequencies, with BW causing greater reductions than MBW. The high significance of these results shows that choice of pre-FFT window is critical in any ABR FFT analysis.

Adult↗
PubMed2005

Neural response correlates of detection of monaurally and binaurally created pitches in humans.

Recent magnetoencephalography (MEG) and functional magnetic resonance imaging studies of human auditory cortex are pointing to brain areas on lateral Heschl's gyrus as the 'pitch-processing center'. Here we describe results of a combined MEG-psychophysical study designed to investigate the timing of the formation of the percept of pitch and the generality of the hypothesized 'pitch-center'. We compared the cortical and behavioral responses to Huggins pitch (HP), a stimulus requiring binaural processing to elicit a pitch percept, with responses to tones embedded in noise (TN)-perceptually similar but physically very different signals. The stimuli were crafted to separate the electrophysiological responses to onset of the pitch percept from the onset of the initial stimulus. Our results demonstrate that responses to monaural pitch stimuli are affected by cross-correlational processes in the binaural pathway. Additionally, we show that MEG illuminates processes not simply observable in behavior. Crucially, the MEG data show that, although physically disparate, both HP and TN are mapped onto similar representations by 150 ms post-onset, and provide critical new evidence that the 'pitch onset response' reflects central pitch mechanisms, in agreement with models postulating a single, central pitch extractor.

Adult↗
PubMed2006

Sequential auditory scene analysis is preserved in normal aging adults.

Normal aging is accompanied by speech perception difficulties, especially in adverse listening situations such as a cocktail party. To assess whether such difficulties might be related to impairments in sequential auditory scene analysis, event-related brain potentials were recorded from normal-hearing young, middle-aged, and older adults during presentation of low (A) tones, high (B) tones, and silences (--) in repeating 3 tone triplets (ABA--). The likelihood of reporting hearing 2 streams increased as a function of the frequency difference between A and B tones (Delta f) to the same extent for all 3 age groups and was paralleled by enhanced sensory-evoked responses over the frontocentral scalp regions. In all 3 age groups, there was also a progressive buildup in brain activity from the beginning to the end of the sequence of triplets, which was characterized by an enhanced positivity that peaked at about 200 ms after the onset of each ABA--triplet. Similar Delta f- and buildup-related activity also occurred over the right temporal cortex, but only for young adults. We conclude that age-related difficulties in separating competing speakers are unlikely to arise from deficits in streaming and might instead reflect less efficient concurrent sound segregation.

Acoustic Stimulation↗
PubMed2003

Early postnatal development of sensory gating.

Sensory gating represents the nervous system's ability to inhibit responding to irrelevant environmental stimuli. In order to characterize the early development of acoustic sensory gating, suppression of auditory evoked potential component P1 (i.e. P50) in response to paired clicks was measured during REM sleep in healthy infants (1-4 months) that were without genetic risk for disrupted sensory gating function (i.e. having a relative with schizophrenia). As a group, the subjects exhibited significant response suppression. A correlation between increasing age and stronger response suppression was uncovered, even within this restricted age range. Parallel changes in sleep physiology could not be ruled out as the explanation for this change. Nevertheless, these results demonstrate that the neural circuits underlying sensory gating are functional very early in postnatal development.

Acoustic Stimulation↗
PubMed2005

Averaged and single-trial brain responses in the assessment of human sound detection.

We investigated sound detection in humans with magnetoencephalography and behavioural measurements. Sounds with intensity increasing smoothly over 125-1000 ms elicited a transient response in auditory cortex with a peak latency in the 200-600 ms range. Importantly, peak latency accurately predicted behavioural reaction time and was unaffected by attentional engagement. Peak amplitude was augmented when the study participants attended to the stimuli and when stimulus duration was decreased. For investigating the cause of these amplitude variations in the averaged response we designed a wavelet-based method for analysing single-trial responses. We found that attention affects the amplitude of the single-trial responses whereas the intensity slope of the stimulus modifies their latency distribution. The transient response reported here holds promise for rapid, objective hearing assessment not requiring a behavioural task.

Attention↗
PubMedDate not supplied

Influence of contralateral masking on bone-conduction thresholds.

Two studies were conducted using normal-hearing listeners. In study 1, bone-conduction (BC) thresholds were obtained with contralateral masking at an effective level (EL) of 30 and 35 dB. In study 2, the EL of the contralateral masking equaled the magnitude of the occlusion effect (OE) plus a safety factor of 10 and 20 dB. Within each study, BC threshold shifts were evident at the higher compared with the lower ELs. Between studies, the highest BC thresholds were always obtained in the presence of the highest SPL of the masker which occurred in the 35 dB EL condition, whereas the lowest BC thresholds were always obtained in the presence of the lowest SPL of the masker which occurred in the OE + 10 dB condition. Even though the BC thresholds were influenced by the amount of contralateral masking, the BC thresholds obtained in each study were in good agreement with the new ANSI S3.26-1981 BC reference thresholds.

Adult↗
PubMed1991

The timing of the processes underlying lateralization: psychophysical and evoked potential measures.

This article describes a technique to measure binaural integration time. A binaural noise with an interaural time difference of 0.8 msec was presented in three conditions: alone, with intervening noise that was identical between the two ears, or with uncorrelated intervening noise. Both behavioral responses and evoked potentials were recorded. When the stimulus was presented in a quiet background, it was accurately detected and lateralized with durations as short as 2 msec. The N1 peak of the evoked potential occurred at approximately 90 msec. When the stimulus occurred as a brief change in an ongoing correlated binaural noise, a duration of 10 msec was necessary before the sound could be accurately lateralized or an evoked potential elicited. The N1 peak occurred at approximately 120 msec. When the stimulus occurred as a change in an ongoing uncorrelated binaural noise, a duration of 60 msec was necessary for the subject to lateralize the stimulus and for an evoked potential to be elicited. The N1 peak occurred at about 130 msec. These results suggest that a period of approximately 60 msec is required to detect the correlation of an ongoing binaural noise and that a somewhat shorter period is necessary to track changes in a sound source that has already been lateralized. The simplicity of this technique makes it an attractive tool for assessing central auditory function.

Acoustic Stimulation↗
PubMed1992

The effects of stimulus rate on detectability of the auditory brain stem response in infants.

This study was undertaken to determine the feasibility of using a fast stimulus rate for auditory brain stem response (ABR) hearing screening in infants. Eighty-four neonates and infants with postconceptional ages (PCA) from 30 to 78 weeks with clear ABRs to click rate of 40/sec at 30 dB HL were retested at 90/sec. Ninety-two percent of infants with PCA > 42 weeks had a clearly identifiable ABR at the 90/sec rate. In contrast, 71% of the infants with PCA between 37 and 42 weeks, and only 50% of the infants with PCA < 37 weeks, had clearly identifiable ABRs at 90/sec. Thus, a 90/sec stimulus rate was not practical on infants < 43 weeks PCA. Accordingly, ABR detectability was assessed to 40 dB clicks at 70/sec compared to the 40/sec rate on 20 infants between 33 and 42 weeks PCA. ABRs were detectable on 85% of this group, which suggests that these parameters may be more reasonable, but further data are needed. ABR measures for hearing screening on infants > 42 weeks and children can be satisfactorily performed at stimulus rates up to 90/sec; however, infants who fail the screening when using a fast stimulus rate should have a repeated measurement at a slower rate to rule out a false positive result.

Acoustic Stimulation↗
PubMed1993

The effect of forward masker duration, rise/fall time, and integrated pressure on auditory brain stem evoked responses in human newborns and adults.

The effects of duration, rise/fall time, integrated pressure, and intensity of a forward masker on the auditory brain stem evoked response (ABR) were examined in three studies. Keeping peak masker intensity constant, integrated masker pressure was a better predictor of ABR latency prolongation than masker duration or rise/fall time in human newborns. Masker effects varied as a function of masker intensity. Greater ABR latency prolongation was observed for more intense maskers. Furthermore, latency prolongation was observed with increasing masker duration for high-intensity, but not low-intensity maskers. Forward masking had a greater effect on newborn wave V latencies than adult wave V latencies; however, increasing masker duration had similar effects on newborn and adult wave V latencies.

Acoustic Stimulation↗
PubMed2003

Middle fossa versus retrosigmoid-transmeatal approach in vestibular schwannoma surgery: a prospective study.

OBJECTIVE: To compare the advantages, disadvantages, and results obtained with the middle fossa and retrosigmoid-transmeatal approaches during pure intracanalar vestibular schwannoma surgery in an attempt to preserve hearing. STUDY DESIGN: Prospective study of patients treated from 1998 to 2001. SETTING: Tertiary care referral center. PATIENTS: Patients with intracanalar vestibular schwannoma (size ranging from 4 to 12 mm), 25 operated on with the retrosigmoid-transmeatal technique and 25 via the middle fossa route. MAIN OUTCOME MEASURES: Facial nerve and auditory function were examined at 1 year with both techniques. Auditory results were also evaluated as a function of tumor size, distance from the internal auditory canal fundus, and internal auditory canal enlargement. RESULTS: The results indicated no significant difference in facial nerve and auditory function results between the two techniques. The retrosigmoid-transmeatal approach, however, yielded better facial nerve function results at discharge. Postoperative hearing was better when the distance from the fundus was greater than 3 mm, when the size of the vestibular schwannoma was equal to or less than 7 mm, and when the internal auditory canal enlargement was less than 3 mm. CONCLUSIONS: The middle fossa approach does not afford any particular advantages over the retrosigmoid-transmeatal approach in terms of auditory results. Facial nerve function is less satisfactory in the short term, when the middle fossa route is used, but can be improved by decompression and gentle displacement of the facial nerve in its labyrinthine portion.

Auditory Perception↗
PubMed2006

Small acoustic neuromas: surgical outcomes versus observation or radiation.

OBJECTIVE: Evaluate factors affecting outcomes of small acoustic neuroma (AN) removal via a middle cranial fossa (MCF) approach, and compare results to published data on observation and radiation therapy. STUDY DESIGN: Retrospective chart review. SETTING: Academic tertiary referral center. METHODS: 162 consecutive patients (ages 19-70) with unilateral AN (0.2-2.5 cm in largest dimension) removed through a MCF approach were reviewed focusing on preservation of hearing, facial nerve function and complications. One hundred thirteen patients had pre-operative word recognition scores (WRS)>70%. RESULTS: Both tumor size and pre-operative WRS were related to post-operative WRS (p<0.01). Overall, at least some hearing was preserved in 94 (60%) of the 156 patients who had hearing before surgery. If the WRS was also >70% (N=113), 56 (50%) maintained WRS>70%. Importantly, WRS for 12 others improved to >70% after surgery. When the patients were stratified by tumor size, the patients with small tumors (2-10 mm) faired better than the overall group. At least some hearing was preserved in 65 (72%) of the 90 patients. If the WRS was also >70% (N=66), 39 (59%) maintained WRS>70%. WRS for eight others improved to >70% after surgery. When the tumor was 1.1-1.4 cm (N=34), the chance of preserving some hearing decreased to 42% (14/33). If the WRS was also >70% (N=23), 9 (39%) maintained WRS>70%. WRS for three others improved to >70% after surgery. When the tumor reached 1.5-2.5 cm (N=35), the hearing preservation rate was 43%. If the WRS was also >70% (N=24), only eight (33%) maintained WRS of 70%, and one other improved to >70%. The addition of intra-operative whole eighth nerve near field monitoring improved results during small tumor ( 70% WRS in 76% (22/29) of those with >70% pre-operative WRS. Good facial nerve function (HB I-II) was achieved in 97% (86% HB I). When tumor size was <or=1.0 cm (N=93), however, good facial nerve function was obtained in 100% (94% HB I). Complications included CSF leak: 9 (5.5%); seizure: 2 (1.2%); and recurrence: 1 (0.6%). CONCLUSION: Our results suggest that removal of unilateral AN through an MCF approach when the tumor is small and hearing is good provides the best opportunity for hearing preservation and normal facial nerve function. Observation historically results in tumor growth in young and middle-age patients with subsequent hearing loss. Radiation may prevent most tumors from growing, and more data are needed to determine long-term tumor control and hearing preservation rates.

Action Potentials↗
PubMed2006

Optimizing the stimuli to evoke the amplitude modulation following response (AMFR) in neonates.

OBJECTIVE: The goal was to identify stimulus features that enhance the detection of the amplitude modulation following response (AMFR) in neonates. The features explored were (1) envelope type, sinusoidal versus a half-wave rectified sinusoid (transposed); (2) best modulation frequency; and (3) spectral content, i.e., tone versus band-pass noise. DESIGN: Results are based on recordings from 149 babies (80 babies in the neonatal intensive care unit and 69 newborn infants). All had passed hearing screening based on the click-evoked ABR. Babies were not sedated. We used carrier frequencies of approximately 500, 1000, 2000, and 4000 Hz and modulation frequencies between approximately 25 and 98 Hz. For the noise stimuli, we used band-pass noise at center frequencies of 500, 1000, 2000, and 4000 Hz. All stimuli were presented through insert earphones delivered simultaneously to both ears, at intensities ranging from 20 to 70 dB SPL. Magnitude squared coherence, phase coherence, and spectral criteria were used to detect criterion AMFRs. We analyzed four measures: (1) percent of satisfied runs; (2) the amplitude of criterion AMFR; (3) time to detect a criterion AMFR; and (4) response strength (e.g., the value of the magnitude squared coherence when it reached criterion minus the critical value it had to exceed for that number of averages all divided by the critical value). RESULTS: (1) The AMFRs evoked by transposed tones were larger and detected faster than those to sinusoidal amplitude modulated tones. Consequently, remaining protocols all used the transposed envelopes. (2) The range of effective modulation frequencies was broad (41 to 88 Hz) across carrier frequencies. (3) The AMFRs evoked by transposed noise were faster and more efficient than those to transposed tones. CONCLUSIONS: In neonates, transposed tones are more effective than sinusoidal amplitude modulated tones in evoking the AMFR, modulation frequencies between 41 to 88 Hz are almost equally effective in evoking the AMFR, and band-pass noises are more effective in evoking the AMFR than tones. These three stimulus factors all add incrementally to the efficiency of evoking the AMFR. The short detection times indicate that the AMFR could be an effective tool for hearing screening.

Acoustic Stimulation↗
PubMed2006

Neural representation of amplified speech sounds.

OBJECTIVE: To determine if (1) evoked potentials elicited by amplified speech sounds (/si/ and /[symbol: see text]/) can be recorded reliably in individuals, (2) amplification alters neural response patterns, and (3) different amplified speech sounds evoke different neural patterns. DESIGN: Cortical evoked potentials were recorded in sound field from seven normal-hearing young adults in response to naturally produced speech tokens /si/ and /[symbol: see text]/ from the Nonsense Syllable Test. With the use of a repeated-measures design, subjects were tested and then retested within an 8-day period in both aided and unaided conditions. RESULTS: (1) Speech-evoked cortical potentials can be recorded reliably in individuals in both aided and unaided conditions. (2) Hearing aids that provide a mild high-frequency gain only subtly enhance peak amplitudes relative to unaided cortical recordings. (3) If the consonant-vowel boundary is preserved by the hearing aid, it can also be detected neurally, resulting in different neural response patterns for /si/ and /[symbol: see text]/. CONCLUSIONS: Speech-evoked cortical potentials can be recorded reliably in individuals during hearing aid use. A better understanding of how amplification (and device settings) affects neural response patterns is still needed.

Acoustic Stimulation↗
PubMed2005

The dependence of the auditory evoked N1m decrement on the bandwidth of preceding notch-filtered noise.

The auditory evoked response is known to be changed by a preceding sound. In this study we investigated by means of magnetoencephalography how a preceding notch-filtered noise (NFN) with different bandwidths influences the human auditory evoked response elicited by the following test stimulus. We prepared white noise (WN) and four NFNs which were derived from WN by suppressing frequency regions around 1 kHz with 1/8-, 1/4-, 1/2- and 1-octave bandwidths. Stimulation for 3 s with this set of noises resulted in differences in responsiveness to a 1-kHz test tone presented 500 ms after the offset of the noises. The N1m response to the 1-kHz test tone stimulus was at a minimum when the preceding NFN had 1/4-octave stop-band frequencies as compared with 1/8-, 1/2- and 1-octave NFN and WN. This N1m decrement is explained by the imbalanced neural activities caused by habituation and lateral inhibition in the auditory system. The results contribute to understanding of the inhibitory system in the human auditory cortex.

Acoustic Stimulation↗