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PubMed1986

P3b peak latency dependency on the point of information delivery within a stimulus.

An acoustic matching experiment was conducted consisting of three quasirandom conditions in which the sequence of tones comprising the second stimulus was changed at the beginning, at the end, or not at all. Latency of maximum positivity (P3b) was measured for each subject between Pz and the averaged mastoids. Evaluation of mismatch conditions demonstrated that peak latency depended on the point of information delivery within the stimulus. Further, peak latency within both mismatch conditions, when adjusted for the timing of tone sequence change, was approximately equally delayed in comparison to match. The implications of the results for information processing models of attention are discussed.

Acoustic Stimulation↗
PubMed1995

The topography of event-related potentials in passive and active conditions of a 3-tone auditory oddball test.

Normalized event-related potential (ERP) data were analysed for topographical differences of ERP amplitude or latency in two conditions of a 3-tone oddball paradigm. The aim was to compare perception-related features relating to tone-type (passive non-task condition) with focussed attention-related features (active discrimination of target from non-target) in 5 ERP components from 23 young healthy subjects. The tones used were a common standard (70%, 0.8 KHz), a deviant standard (15%, 2 KHz) and a 1.4 KHz tone (15%, t) also used as the target (T). A site x tone interaction was obtained for P1 amplitude (augmenting with pitch anterior to posterior). The opposite tendency was seen for P2 to the right of midline maxima. No interaction was obtained for N1 amplitude. Condition became relevant for the N2-P3 complex. Frontal N2 amplitude increased after rare tones in the active condition. Posterior P3 peak size distinguished between tone (more widespread response to the common tone) and condition (more right-sided in the passive condition). The common tone elicited more widespread shift to the right than the rare tones. Latency was affected by condition from the P2 onwards and confirmed many of the amplitude interactions. This report extends and qualifies well-known main effects of tone and condition through main site effects to lateral sites. It supports claims of multiple sources of ERP components, except for N1 and P2. The contributions of these sources are influenced by tone-features (from P1) and the presence or absence of focussed attention (from the N2-P3 complex).

Adult↗
PubMed1998

Anomalous screening outcomes from click-evoked otoacoustic emissions and auditory brainstem response tests.

Transiently evoked otoacoustic emissions (TEOAE) and auditory brainstem response (ABR) tests were used in parallel to screen 862 neonates with risk factors for hearing loss. Seven neonates (0.81%) passed on TEOAE screen yet failed on ABR in one ear (six neonates) or both ears (one neonate). This combination of results has been termed 'anomalous'. Examination of audiometric results obtained on follow-up shows that in one ear of one neonate the result was consistent with the later confirmed audiogram shape. The explanation for the anomalous results in the remaining ears is unclear although neural maturation and the effects of hyperbilirubinaemia are possibilities. There were no instances of progressive or retrocochlear hearing loss identified. None of the seven neonates had better ear hearing loss of > or = 40 dB on long term follow-up.

Acoustic Stimulation↗
PubMed1993

Auditory brainstem responses recorded at fast stimulation rates using maximum length sequences.

There are now commercially available systems which can provide maximum length sequence averaging techniques. This study examines the effects on auditory brainstem response amplitude and latency of using such a system and stimulating at rates from 9 to 1000 clicks/s. As expected there is considerable adaptation of the response such that at 1000 clicks/s wave V amplitude is only approximately 8% of its low stimulation rate value. As the stimulation rate is increased so the test time taken to obtain a response of the same signal-to-noise ratio as a conventional recording decreases. This process continues up to a maximum click rate of about 200 clicks/s. Thereafter, the response adapts so rapidly that further increases of rate lead to a worsening of performance. Thus, the optimum stimulation rate appears to be of the order of 200 clicks/s and this can give a speed improvement by a factor of approximately 2.8 over conventional recordings taken at 9 or 10 clicks/s.

Adaptation, Physiological↗
PubMed1999

Communicative ability in an audiological perspective. Theory and application to post-secondary school students.

The underlying assumption in the present study is that the individual's speech and hearing communicative ability is composed of three components, each corresponding to different functional systems of the brain: afferent functions (A) represent the auditory activity and sound perception largely corresponding to activity in the ascending auditory pathways. The central functions (C) include cortical auditory and language abilities controlled in parts of the left temporal lobe and subcortical centres. The efferent functions (E) consist of speech motor processes and articulation. A test battery of 20 tests measuring several aspects of afferent, central and efferent functions was applied to 11 hearing-impaired post-secondary school students and several control groups. All data were normalized with the normal materials as references. Individual communicative profiles were obtained from these primary data, which consisted of audiometric tests (tone and speech audiometry, impedance tests, brainstem response audiometry and phase audiometry), sound environmental tests with hearing aids (directional speech-in-noise, word localization, sound environment identification test), and language tests (reading tests, prosody, auditory memory and recall, phonology and articulation). Since the central functions cannot truly and directly be determined in hearing-imparied subjects, they were assessed under optimal listening conditions. Furthermore, central functions were estimated according to three different models: distributive, parallel model (model 1), multiplicative, serial model (model 2) and compensatory model (model 3). On the basis of these models, a three-component description of the communicative ability consisting of A,C and E functions was obtained. It was found that C and E functions were largely independent of the adult afferent functions, but C functions were negatively correctly to hearing in childhood. A preliminary comparison between the tests and a comparison between the models was performed by predicting benefit of hearing aid. Model 3 gave the best prediction. Beyond the three-component A,C, and E characterization of the students, a total communicative ability score could be calculated giving values from 37% to 79% of the normal mean. On the basis of the conceptual and statistical analyses, the test battery could be reduced to include tone 0-12 years, tone adults, word localization test (afferent); word chain, lecture test (central), articulatory test (efferent) and audiovisual test. The simple algorithm of adding the normalized loss of afferent (peripheral) function to the normalized results of the acoustic central tests seems to be promising for isolation for the central auditory capacity even in cases with peripheral impairment. It is concluded that a wider perspective is desirable in the diagnostic evaluation of the hearing-impaired individual in order to understand his communicative abilities and form a cornerstone in the planning of rehabilitation in conjunction with social and psychological factors.

Adolescent↗
PubMed2000

Effect of age on sensory gating of the sleep state-dependent P1/P50 midlatency auditory evoked potential.

The P1/P50 midlatency auditory evoked potential is a sleep state-dependent waveform present during waking and rapid eye movement (REM) sleep and absent during slow-wave sleep. The P50 potential was studied in normal male and female subjects of various ages including post-pubertal adolescents (12-19 yrs), young adults (24-39 yrs), middle-aged adults (40-55 yrs) and older adults (55-78 yrs). There were no statistically significant differences in the mean peak amplitude or mean peak latency of the P50 potential between males and females or between age groups. Using a paired stimulus paradigm, the degree of sensory gating of the P50 potential was tested at three different interstimulus intervals (ISIs), 250, 500 and 1000 msec. There were no statistically significant differences in the sensory gating of the P50 potential between males and females. However, there was a significant decrease in sensory gating of the P50 potential in the adolescent group compared to each of the other age groups at the 250 msec ISI, but not at the 500 or 1000 msec ISI. These results suggest the presence of decreased sensory gating in normal adolescents compared to normal, older age groups.

Adolescent↗
PubMed2002

[Sensitivity of the neurons in the auditory inferior colliculus of mice to the direction of the shift of broadband spectral notch noise].

Series of a notch noise with regular shifts of the notch center frequency: one--from low frequencies to high frequencies and the other--from high frequencies to the low, were synthesized. The notch noise series imitated sound source vertical moving. Single neuron's responses of inferior colliculus of the house mouse (Mus musculus) to the notch-noises altered with notch central frequency varying through excitatory and inhibitory frequency response areas in neurones' receptive fields. The neural responses alteration to the notch noise varying depended on the bandwidth of notch. Disinhibition in inhibitory side band could be higher if the notch overlying the inhibitory areas followed the notch overlying the excitatory areas. The data obtained make it possible to consider the excitatory and inhibitory interaction as a mechanism of neural sensitivity to the notch moving direction. Neurones' response set could provide information about sound source moving over auditory space.

Acoustic Stimulation↗
PubMed2000

Gingko biloba (Rökan) therapy in tinnitus patients and measurable interactions between tinnitus and vestibular disturbances.

Tinnitus is one of the most important symptoms in neurootology after vertigo, nausea, and hearing loss. In most cases, the origin of the tinnitus remains inexplicable. Well-known, however, is that tinnitus may arise in any part of the hearing pathway (i.e., both within the cochlea receptor and in the temporal lobe and projections). Tinnitus also is associated frequently with vertigo, nausea and hearing loss. An age predominance exists, with tinnitus more common among those older than 40 years. From this starting point, a great demand exists today for new ideas and developments in the diagnosis and treatment of tinnitus.

Audiometry↗
PubMed1991

Treatment of noise induced hearing loss.

In most textbooks, it is stated that noise-induced hearing loss (NIHL) is an irreversible impairment of hearing. This is certainly true for the slowly, over time acquired NIHL. Working for years in a very noisy environment is causing a gradual killing of hair cells in the inner ear, with no hope for recovery. The other way of acquiring NIHL is by means of exposure to impact noise, and may cause various degree of impairment of the hair cell cilia, depending on the energy in the impulsive noise. If the cilia are completely broken, the chance for recovery is probably zero. In many instances, the result of exposure to impulsive noise, for instance from rifle shooting, may mainly be a disarrangement of the cilia. It will be shown an example of recovery from grade III NIHL to grade I after treatment of the exposed person with a stay in silence, i.e. in environmental noise below 70 dB(A), for three weeks.

Adult↗
PubMed1990

[Possibilities of studying the auditory evoked potentials in patients with various forms of extrapyramidal pathology].

As many as 47 patients with different extrapyramidal hyperkinesias were examined. In addition to the methods commonly accepted in otoneurology, use was made of the method of recording short-wave auditory evoked potentials (SAEP). The parameters of SAEP were correlated to the degree of auditory and vestibular function impairment. The data obtained indicate that the majority of patients with hyperkinesias manifest a well-defined reduction of the amplitude and an increase of the latent period of the late waves of SAEP, which attests to the interest of the cerebral structures.

Acoustic Stimulation↗
PubMed1993

Sudden hearing loss in multiple sclerosis: case report.

This case illustrates the occurrence of a sudden hearing sensitivity loss that, in all likelihood, was the result of brainstem disorder resulting from multiple sclerosis (MS). Subject LD is a young woman who developed a sudden hearing loss while hospitalized for exacerbation of symptoms related to multiple sclerosis. By her own report, she had normal hearing in her left ear at the time of hospitalization. Four days after admission, she developed a hearing loss in her left ear, accompanied by roaring tinnitus and fullness. An audiologic evaluation revealed a substantial high-frequency sensitivity loss in the left ear. The combination of absent acoustic reflexes, depressed speech understanding, abnormal Bekesy audiometry, and an abnormal auditory brainstem response (ABR) was consistent with brainstem site of disorder. Over the next 2 weeks, hearing sensitivity recovered to within normal limits. This change in hearing sensitivity coincided with the recovery of acoustic reflexes, improvement in speech understanding, and partial recovery of the ABR.

Adult↗