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At least 289 records · Page 16Linked to original sources
PubMed1992

Electrically evoked auditory brainstem response monitoring of auditory brainstem implant integrity during facial nerve tumor surgery.

Evoked potentials identified as electrically evoked auditory brainstem responses (EABRs) have been recorded from a patient in response to electrical stimulation of the cochlear nucleus via an auditory brainstem implant. Recording such EABRs during surgery for removal of an ipsilateral facial nerve tumor provided a means to monitor the integrity of the implant. The presence of stable EABRs similar to those obtained before surgery indicated that the lead wires had not been severed and that the implanted electrodes had not been dislodged. EABR recording may also be useful for assisting with positioning the stimulating electrodes during initial implantation surgery, by verifying that stimulation can activate the auditory system.

Anesthesia↗
PubMedDate not supplied

Brainstem auditory-evoked potential assessment of auditory function and congenital deafness in llamas (Lama glama) and alpacas (L. pacos).

Auditory function of llamas and alpacas was assessed objectively by means of brainstem auditory-evoked response audiometry (BAER) to establish the normal hearing range and to test the hypothesis of a correlation between blue eyes, white coat, and deafness. Sixty-three camelids were available for the study. Thirteen animals had blue irides; 1 animal had 1 blue and 1 pigmented iris. Wave latencies, amplitudes, and interpeak latencies were measured under general anesthetic. Click stimuli (dB [HL]) were delivered by an insert earphone. Four to five positive peaks could be detected; waves I, II, and V were reproducible; wave II appeared infrequently; and wave IV generally merged with wave V to form a complex. Peak latencies decreased and peak amplitudes increased as stimulus intensity increased. A hearing threshold level of 10-20 dB (HL) was proposed as the normal range in llamas and alpacas. None of the animals with pigmentation of coat and iris showed any degree of hearing impairment. Seven of the 10 blue-eyed, pure-white animals were bilaterally deaf and one of them was unilaterally deaf. However, 2 blue-eyed, white animals exhibited normal hearing ability. Three blue-eyed animals with pigmented coat did not show any hearing impairment. All white animals with normal iris pigmentation had normal auditory function; so did the 1 animal with 1 normal and 1 blue iris. The high frequency (78%) of bilaterally deaf animals with pure white coat and blue iris pigmentation supports the hypothesis of a correlation between pigmentation anomalies and congenital deafness in llamas and alpacas.

Acoustic Stimulation↗
PubMed1992

Effects of auditory imagery on the detection of a pure tone in white noise: experimental evidence of the auditory Perky effect.

The purpose of this study was to examine whether the auditory image of a pure tone facilitates or interferes with the auditory perception of the pure tone. The masked threshold of a pure tone in white noise with and without the image of a pure tone was compared. It was shown that, in contrast to Farah and Smith's (1983) finding of facilitation, imagery interfered with the detection of the pure tone only when the frequency of the imagined tone and the detected tone was the same. This interference was interpreted as showing the assimilation of the signal tone into imagery, i.e., the effect described by Perky in 1910, occurred in the auditory modality. An explanation of the differences between findings of interference and facilitation is offered.

Adult↗
PubMed2002

Correlation between auditory function and internal auditory canal pressure in patients with vestibular schwannomas.

OBJECT: Hearing loss is the most common presenting symptom in patients who harbor a vestibular schwannoma (VS). Although mechanical injury to the cochlear nerve and vascular compromise of the auditory apparatus have been proposed, the exact mechanism of this hearing loss remains unclear. To test whether pressure on the cochlear nerve from tumor growth in the internal auditory canal (IAC) is responsible for this clinical finding, the authors prospectively evaluated intracanalicular pressure (ICaP) in patients with VS and correlated this with preoperative brainstem response. METHODS: In 40 consecutive patients undergoing a retrosigmoid-transmeatal approach for tumor excision, ICaP was measured by inserting a pressure microsensor into the IAC before any tumor manipulation. Pressure recordings were correlated with tumor size and preoperative auditory evoked potential (AEP) recordings. The ICaP, which varied widely among patients (range 0-45 mm Hg), was significantly elevated in most patients (median 16 mm Hg). Although these pressure measurements directly correlated to the extension of tumor into the IAC (p = 0.001), they did not correlate to total tumor size (p = 0.2). In 20 patients in whom baseline AEP recordings were available, the ICaP directly correlated to wave V latency (p = 0.0001), suggesting that pressure from tumor growth in the IAC may be responsible for hearing loss in these patients. CONCLUSIONS: Tumor growth into the IAC results in elevation of ICaP and may play a role in hearing loss in patients with VS. The relevance of these findings to the surgical treatment of these tumors is discussed.

Adult↗
PubMed2000

Brainstem auditory evoked potentials and cochlear microphonics in the HMSN family with auditory neuropathy.

UNLABELLED: The aim of this work was to assess the hearing impairment in patients with hereditary motor and sensory neuropathy (HMSN). Elevation of pure tone thresholds in the presence of preserved inner ear function as suggested by cochlear microphonics (CM), absent or markedly abnormal brainstem auditory evoked potentials (BAEP), and elevation of speech perception out of proportion to the pure tone loss were found in the patients. From 28 members of a Gypsy family, we examined two siblings aged 31 and 30 years and their nephew aged 20 years, all suffering from HMSN that was associated with auditory neuropathy. All three affected members with difficulty of understanding speech had following investigations: pure tone and speech audiograms, BAEP, cochlear microphonics, and nerve conduction studies (NCV). RESULTS: the older two siblings had a flat 80 dB audiogram, whereas the younger one has flat 20 dB audiogram on the Lt. ear and 30 dB audiogram on the Rt. ear. All had no speech comprehension and no BAEP. Two patients had preserved cochlear microphonics on one ear. Peripheral nerves were electrically not elicitable, however, at the beginning of the disease nerve conduction was slow. CONCLUSION: in all three affected members with distinct clinical picture of HMSN their hearing impairment was proved to be due to severe auditory neuropathy in the presence of preserved inner ear function.

Adult↗
PubMed2001

Maximum length sequences-auditory brainstem responses from children with auditory processing disorders.

This study was designed to evaluate maximum length sequences-auditory brainstem responses (MLS-ABR) in children with auditory processing disorders and to compare these results with a normal control group matched for age, intelligence, and gender. Although each waveform was analyzed for the presence of waves I, III, and V, the primary focus was wave V. Although absolute latency measures for wave V were obtained from all subjects, waves I and III were not always identified. Although the results showed latency increases for all waveforms in both groups, the only significant difference noted was an increase in wave V latency for both the left and right ears in the clinical group. These results suggest that the MLS-ABR may be useful in the assessment of auditory processing disorders. Implications for the potential use of the MLS-ABR in management programs are discussed.

Adolescent↗
PubMed1975

Effects of auditory and pictorial-auditory stimulus enrichment on the verbal abstracting abilities of low-SES children.

Sixty-four low-SES Caucasian children, mean age 8.3 years, with high- and lowintellectual ability, were given a verbal similarities task. One-half of the subjects (the control group) received nonenriched items (2 exemplars of each concept on Presentation 1, which were repeated on Presentation 2), and half (the experimental group) received enriched items (2 exemplars of each concept on Presentation 1 and 4 exemplars on Presentation 2). Stimuli were presented in either the auditory or pictorial-auditory mode. The low-ability experimental group achieved abstracting gain scores greater than those of the lol-ability control group and greater than those of the high-ability experimental group. The low-ability experimental group achieved scores equivalent to those of the high-ability group under the pictorial-auditory enriched condition. Implications of these findings were discussed relative to academic performance of EMR children.

Acoustic Stimulation↗
PubMed1992

[Intraoperative monitoring auditory function during surgery of internal auditory canal and C-P angle].

Intraoperative measurement of electrocochleography, auditory brainstem responses and eighth nerve action potentials are utilized to assess the functional integrity of the cochlea and cochlear nerve. All such assessments have only one purpose: for warning the surgeon the possibility of damage the auditory system or its surrounding structure. Eighteen patients with various otoneurological diseases undergoing surgery had intraoperative monitoring of such evoked electrophysiological responses. Hearing was preserved in sixteen patients. However, the CM/N1 in ECochG still keep for a few minutes even after transection of the cochlear nerve and there is another disadvantage of need for signal averaging in BAER. Recording of the response of the the auditory nerve directly from the eighth nerve provides the surgeon with immediate information when an insult has been made to the cochlear and eighth nerve. Therefore, combination of these three measurements are recommended depending on the situation.

Audiometry, Evoked Response↗
PubMed1990

Function of dog's auditory cortex in tests involving auditory location cues and directional instrumental response.

Twenty one dogs, distributed into four groups, were trained pre-operatively in differentiation of auditory location or frequency cues. In each group instrumental responses, reinforced by food consisted in placing by the animal its right paw on the side levers. The first differentiation, go-left, go-right task with two location cues, required the animal to place its paw on the lever opposite to the source of the cue. The second differentiation task with the same location cues required placing the paw on the lever located close to the cue. The third task, involving 700 Hz vs. 1,000 Hz tone, required responding to one lever to the presentation of one tone and responding to the opposite lever to the presentation of the other. The last task was a symmetrically reinforced go, no-go differentiation with, again, auditory location cues: the animals were trained to place the paw on a lever to one location cue and to withhold this response to the other location cue. Bilateral ablation of the primary auditory cortex produced a considerable impairment of the performance of the two go-left, go-right tasks involving location cues. The go-left, go-right task employing frequency cues, and the symmetrically reinforced go, no-go task with location cues, were only slightly disturbed by this lesion.

Animals↗
PubMed1979

Common dimensions of visual and auditory agnosia and an explanation of the auditory recognition deficit in aphasia.

An experimental analysis of auditory recognition disturbances was performed; 81 patients with localized cerebral lesions were examined with a recognition test for meaningful sounds and with a nonverbal intelligence test (Block Design). Sensory stimulation was 5 or 15 sec for each sound. Nonverbal intelligence accounted for a considerable and significant amount of variance in recognition performance. The aphasic group was more impaired in auditory recognition than were both the other groups, i.e., patients with right or left hemispheric lesions without aphasia. The auditory recognition disturbance in the aphasic group depended to a significant extent on stimulus duration, which means a slowing down of the recognition process in aphasia. The analogies to studies on visual agnosia are striking. In both modalities, recognition depends on intellectual functioning, sensory disturbances or reduced sensory input, and the presence of aphasia.

Adult↗
PubMed1977

Development of auditory function in newborn infants revealed by auditory brainstem potentials.

Auditory brainstem potentials were recorded from scalp electrodes in 42 infants ranging in gestational age from 25 to 44 weeks. The latencies of the various potential components decreased with maturation. Wave V, evoked by 65-dB sensation level clicks, changed in latency from 9.9 msec at 26 weeks of gestation of 6.9 msec at 40 weeks of gestation. Central conduction times in the auditory pathway also decreased with maturation from 7.2 msec at 26 weeks to 5.2 msec at 40 weeks. The effects of brainstem and cochlear disorders on auditory brainstem potentials were noted in several abnormal infants. The application of all of these techniques could permit an objective definition of both normal and abnormal sensory processes in newborn infants.

Action Potentials↗
PubMedDate not supplied

[Relationship between auditory disability and auditory threshold in acute acoustic trauma: pilot study].

The aim of this study was to determine the relationship existing between auditory disability, according to WHO 1980, and pure tone audiometry threshold in noise induced hearing loss. Disability was evaluated on the basis of a questionnaire submitted to 286 subjects with acoustic trauma. Answers obtained were considered reliable on the basis of statistical analysis. Results showed that subjects with disability have an higher pure tone threshold than subjects without auditory disability. However it appears difficult to determine a precise threshold level ever which auditory disability may be considered present. The Authors suggest that this limit could be determined on the basis of pure tone threshold at the 10th centile of the group of subjects with disability or at the 90th centile of subjects without disability.

Adult↗
PubMed1998

Auditory and auditory-visual recognition of clear and conversational speech by older adults.

Research has shown that speech articulated in a clear manner is easier to understand than conversationally spoken speech in both the auditory-only (A-only) and auditory-visual (AV) domains. Because this research has been conducted using younger adults, it is unknown whether age-related changes in auditory and/or visual processing affect older adults' ability to benefit when a talker speaks clearly. The present study examined how speaking mode (clear vs conversational) and presentation mode (A-only vs AV) influenced nonsense sentence recognition by older listeners. Results showed that neither age nor hearing loss limited the amount of benefit that older adults obtained from a talker speaking clearly. However, age was inversely correlated with identification of AV (but not A-only) conversational speech, even when pure-tone thresholds were controlled statistically.

Aged↗
PubMed2002

Comparison between local field potentials and unit cluster activity in primary auditory cortex and anterior auditory field in the cat.

Multi-unit (MU) activity and local field potentials (LFP) were simultaneously recorded from 161 sites in the middle cortical layers of the primary auditory cortex (AI) and the anterior auditory field (AAF) in 51 cats. Responses were obtained for frequencies between 625 Hz and 40 kHz, at intensities from 75 dB SPL to threshold. We compared the response properties of MU activity and LFP triggers, in terms of characteristic frequency (CF), threshold at CF, minimum latency and frequency tuning-curve bandwidth 20 dB above threshold. On average, thresholds at CF were significantly lower for LFP events than those for MU spikes (4.6 dB for AI, and 3 dB for AAF). Minimum latencies were significantly shorter for LFP events than for MU spikes (1.5 ms in AI, and 1.7 ms in AAF). Frequency tuning curves were significantly broader for LFP events than those for MU spikes (1.0 octave in AI, and 1.3 octaves in AAF). In contrast, the CF was not significantly different between LFP events and MU spikes. The LFP results indicate that cortical neurons receive convergent sub-cortical inputs from a broad frequency range. The sharper tuning curves for MU activity compared to those of LFP events are likely the result of intracortical inhibitory processes.

Acoustic Stimulation↗
PubMed2004

Establishing normal hearing with the dichotic multiple-frequency auditory steady-state response compared to an auditory brainstem response protocol.

OBJECTIVE: To determine the clinical usefulness of the dichotic multiple-frequency (MF) auditory steady-state response (ASSR) technique for estimating normal hearing compared to a 0.5-kHz tone burst and broadband click auditory brainstem response (ABR) protocol in a sample of adults. MATERIAL AND METHODS: A comparative experimental research design was selected in order to compare estimations of normal hearing obtained with the dichotic ASSR technique at 0.5, 1, 2 and 4 kHz with a 0.5-kHz tone burst and broadband click ABR protocol. The recording times required for each procedure were also compared. Normal-hearing subjects (n = 28) were selected according to immittance values within normal limits and pure-tone behavioural thresholds of < 25 dB HL across frequencies. RESULTS: The dichotic MF ASSR estimated normal hearing to be, on average, 30-34 dB HL across the range 0.5-4 kHz. The mean estimate of normal hearing for 0.5 kHz using tone burst ABRs was 30 dB nHL and the mean click ABR threshold was 16 dB nHL, i.e. 14-18 dB better than the ASSR thresholds. The dichotic MFASSR technique recorded 8 thresholds (4 in each ear) in a mean time of 23 min. The ABR protocol recorded 4 thresholds (2 in each ear) in a mean time of 25 min. CONCLUSION: Both the dichotic MF ASSR and ABR protocols provided a time-efficient estimation of normal hearing. There was no significant difference between the tone burst ABR and MF ASSR techniques in terms of estimation of normal hearing at 0.5 kHz. The dichotic MF ASSR technique proved more time-efficient by determining more thresholds in a shorter time compared to the ABR protocol.

Adolescent↗
PubMed2006

A comparison of 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) thresholds in awake adult subjects.

Evoked potential thresholds using the 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) were recorded at 500 Hz and 4000 Hz test frequencies in 36 subjects with normal acuity, and 30 subjects with sensorineural hearing loss. ASSR threshold sensation levels (SLs) were lower in ears with greater degrees of hearing loss, and for the 500 Hz stimulus. Mean SLs (maximum duration of a single recording: 89 seconds) were as follows at 500 Hz and 4000 Hz respectively: normal hearing group, 16.9+/-10.3 dB and 42.4+/-14.4 dB; mild-moderate group, 10.6+/-8.8 dB and 23.8+/-8.1 dB; severe-profound group, 10.0+/-13.2 dB and 21.5+/-18.9 dB. CAEP SLs showed no change with hearing level and CAEP/behavioural differences were similar at each test frequency. Mean SLs for CAEP threshold (single recording duration: 84 seconds) at 500 Hz and 4000 Hz respectively were: normal hearing group, 10.3+/-6.4 dB and 11.5+/-3.8 dB; mild-moderate group, 8.4+/-7.4 dB and 13.2+/-12.4 dB; severe-profound group, 11.0+/-6.6 dB and 15.9+/-16.4 dB. The results of this study suggest that while both 40 Hz ASSR and CAEP can reflect the behavioural audiogram, CAEPs may provide a more reliable estimate of hearing in awake adults.

Acoustic Stimulation↗
PubMed1986

The central auditory conduction at term date and three months after birth. IV. Auditory cortical responses.

Auditory cortical responses (ACRs) were recorded in 25 healthy mature newborns with a follow-up at 3 months. The waveform, latencies and amplitudes for the ACRs for this time period are studied. Topographic differences between the central and central-temporal derivations and changes between term and 3 months are found with respect to latencies and amplitudes for different peaks and troughs. The ACRs, obtained as a part of a protocol covering the entire auditory afference, offer consistent parameters, which can be used to study developmental neurophysiological properties of audition and which are potential diagnostic tools for the detection of deviant sensory or mental development.

Auditory Cortex↗
PubMed1987

The maturation of the central auditory conduction in preterm infants until three months post term. II. The auditory brainstem responses (ABRs).

Auditory evoked brainstem responses (ABRs) were recorded in 65 preterm infants (serially in 55 of them), divided into 5 groups, according to their gestational age (GA). The recording sessions were performed at 8 conceptional age levels (CA = GA + chronological age), of which the last two were about 40 and 52 weeks CA. The number of recording sessions varied from one to seven. A full set of ABR latency and amplitude parameters was analyzed including peaks I, II, IIN, III, V and IIc, IIINc and Vc as well as some interpeak latency differences (IPLDs), and the amplitude ratios. The detectability of the different components in the ABR tests at 70 dB reached 80-100% at about 32 weeks CA. The side of stimulation nor the state of vigilance influences the detectability. The degree of prematurity in the 5 GA groups did not influence the development of the parameters. Neither the side of stimulation nor generally the state of vigilance give rise to different parameter values. The thresholds show an age dependent decrease, which is also determined by central maturation. The differential development of the latency decrease of the ABR parameters with increasing conceptional age can be associated with morphological maturational processes and may add weight to the arguments in the delineation of the sources of the ABR. The ipsi- and contralateral central conduction V-II and Vc-IIc do not show latency differences at any CA level. The components IIc and Vc, however, lagged behind in absolute latency compared with II and V. It is concluded that the ABR is a powerful instrument for the study of the maturation of the human auditory pathway in the brainstem. In view of the variability, the detectability and the complex changes within the ABR during the preterm period, its application for clinical purposes during this period has a limited value.

Analysis of Variance↗