Short-latency Auditory Evoked Potentials Research Articles

CHANGES IN STEM EVOKED POTENTIALS IN CHILDREN WITH AUTISM SPECTRUM DISORDERS

Autism spectrum disorders (ASDs) are neurodevelopmental disorders that are becoming more and more common. The steady incidence rate and delayed diagnosis require the expansion and improvement of diagnostic methods for early correction and improvement of patients’ quality of life.
 The purpose of the study is to identify the changes in short-latency auditory evoked potentials (SAEPs) in children at risk for ASD formation, as well as in children with ASDs in order to determine the severity of speech delay and to draw up a corrective plan.
 Materials and Methods. The authors examined 50 children with ASDs: 40 boys and 10 girls. The control group consisted of 23 children of the same age without clinical signs of ASDs and speech delay (15 boys and 8 girls). When registering SAEPs, peak 5 dominant latency was determined. The distribution parameters of the latent period values of SAEP peaks were estimated.
 Results. A slight delay in peak 4 impulse conduction was found in children with ASDs over the age of 5. In the earlier age groups, these changes were considered clinically insignificant. When assessing peak 5, a sharp decrease in the speed of acoustic signals was observed in all age groups compared with the control. The results of SAEP assessment showed a pronounced slowdown in the conduction of auditory information by the brainstem at the mesencephalic level in children with ASDs compared to the control.
 Conclusion. Children with ASDs are characterized by disturbances in the speed and frequency characteristics of brainstem auditory tracts. The revealed decrease in peak 5 velocity is important for diagnosis, including differential diagnosis of speech delay, drawing up a corrective plan and carrying out early corrective measures, and for the prevention of developmental disorders in young children.

Monaural and dichotic forward masking in the dolphin's auditory system.

Short-latency auditory-evoked potentials (AEPs) were recorded non-invasively in the bottlenose dolphin Tursiops truncatus. The stimuli were two sound clicks that were played either monaurally (both clicks to one and the same acoustic window) or dichotically (the leading stimulus (masker) to one acoustic window and the delayed stimulus (test) to the other window). The ratio of the levels of the two stimuli was 0, 10, or 20dB (at 10 and 20dB, the leading stimulus was of a higher level). The inter-stimulus intervals (ISIs) varied from 0.15 to 10ms. The test response magnitude was assessed by correlation analysis as a percentage of the control (non-masked) response. At monaural stimulation, the test response was of a constant magnitude (5-6% of the control) at ISIs of 0.15-0.3ms and recovered at longer ISIs. At dichotic stimulation, the deepest suppression of the test response occurred at ISIs of 0.5-0.7ms. The response was slightly suppressed at short ISIs (0.15-0.3ms) and recovered at ISIs longer than 0.5-0.7ms. The relation of parameters of the forward masking to echolocation in dolphins is discussed.

Correlation between the main parameters SLAEP and rheoencephalography in patients with acoustic trauma

Correlation between the main parameters SLAEP and rheoencephalography in patients with acoustic trauma

MENINGIOMAS OF THE CEREBELLAR TENTORIUM: THE RESULTS OF SURGICAL TREATMENT

Aim of the study was to evaluate the surgeries of tentorial meningiomas in Neurosurgical Department No.1 of the Novosibirsk Institute of Traumatology and Orthopedics. Material and methods. Study includes 64 patients with tentorial meningiomas of different location, treated surgically from 2008 to 2017. Among them 55 (85.9 %) were female patients and 9 were male (14.1 %) with average age of 62.9 years in females and 56.7 years in males. For diagnostic purposes, the patients were performed brain magnetic resonance imaging and/or computed tomography with or without contrast agents. In this series, 83 % of the tumors were of large or giant (with diameter of more than 4 cm). In 63 cases the tumors were typical meningiomas and only 1 case was a malignant anaplastic meningioma. Results . All patients were treated surgically in one or two steps. Overall, there were 70 standard microsurgical resections. Electromyography with Neuropack-2 («NIHON KOHDEN Corp.», Japan) was performed to control brain stem function during the surgery, with short latency auditory evoked potentials (SLAEPs) received. When sinus walls were affected, the tumor matrix was processed with 20W neodymium laser in coherent mode and ablation. In 63 cases, gross-total resection was achieved: Simpson I (76.6 %, n = 49) and Simpson II (21.8 %, n = 14). One patient (1.6 %) was treated with subtotal resection because of complicated surgical approach and massive transverse sinus and sinus confluence bleeding. Post-operative mortality was 3.1 % (2 cases). SLAEP data did not demonstrate any significant irritation or damage to the brain stem with performed surgical approaches. There were no infections of the surgical wound, meninges, brain or CSF leaks after the surgery. Discussion . Tentorial meningiomas are rare brain tumors treated with gross-total tumor resection when possible. Performed surgeries resulted in mild functional decrease in quality of life, but Karnofsky scale for each patient was returning to its original state in 2 weeks. Complications, including neurological disability, presented in 19 % (n = 12) of the patients, and post-operative mortality did not exceed the common literature data. Most of the focal neurological disabilities have disappeared in 2 weeks after the surgery.

The hearing function in the premature children following their treatment with the use of ototoxic antibiotics

The objective of the present study was the evaluation of the state of the auditory function in the premature children during the first year of life who underwent the neonatal treatment with various ototoxic antibiotics. A total of 232 newborn infants were available for the examination by the methods designed for recording distortion product optoacoustic emission (DPOAE) and short-latency auditory evoked potentials (SAEPs). The 'Statgraphics Centurion XV' program was used for the statistical treatment of the data obtained in the study. The results of recording DPOAE and SAEPs in 232 prematurely born children of different gestational age were used to evaluate their auditory function under conditions of treatment with various ototoxic antibiotics during the early neonatal period. It was shown that such treatment is likely to have an impact on the hearing function of premature children throughout the entire first year of life. Such influence can manifest itself as the enhanced threshold of the appearance of SAEPs peak V and the selective distortion of evoked responses recorded with the help of the DPOAE technique at a frequency of 4.6 kHz. It is concluded that all prematurely born children should be under observation of an otorhinolaryngologist-surdologist throughout the entire first year of life and, if appropriate, undergo the rehabilitative treatment at the earliest possible time. Moreover, the children with this condition must remain under the thorough follow-up care during at least 3 years including the yearly audiological evaluation and the comparative analysis of the results of previous observations for the timely identification of possible disturbances in the hearing function.

Assessment of the Velocity of Traveling Waves in the High-Frequency Cochlea of the Dolphin

Short-latency auditory evoked potentials (SLAEP) produced in response to sound impulses with strictly specifi ed 0.5-oct frequency bands, from 11.2–16 to 90–128 kHz, were recorded in bottle-nose dolphins. Using stimuli of constant intensity, SLAEP amplitude depended on the spectral frequency of the stimulus: the higher the frequency, the greater the amplitude. Response shape showed little dependence on spectral band, though the response delay changed with frequency: the higher the frequency, the shorter the delay. The differences in delays between the responses to low-frequency (11.2–16 kHz) and high-frequency (90–128 kHz) stimuli was 0.3 msec. This difference in response delays could be attributed to the propagation time of the traveling wave in the cochlea; the results obtained here were used to calculate the velocity of the traveling wave. These assessments of velocity were from 38.2 oct/msec at the proximal (high-frequency) end of the basilar membrane to 2.8 oct/msec at the distal (low-frequency) end. Comparison of traveling wave velocities in humans and dolphins showed that traveling wave velocity was not linked to the location on the cochlea, but to the characteristic frequency.

Analysis of auditory information in the brains of cetaceans

A characteristic feature of the brains of toothed cetaceans is the exclusive development of the auditory neural centers. The location of the projection sensory zones, including the auditory zones, in the cetacean cortex is significantly different from that in other mammals. The characteristics of evoked potentials demonstrate the existence of several functional subdivisions in the auditory cortex. Physiological studies of the auditory neural centers of cetaceans have been performed predominantly using the evoked potentials method. Of the several types of evoked potentials available for non-invasive recording, the most detailed studies have been performed using short-latency auditory evoked potentials (SLAEP). SLAEP in cetaceans are characterized by exclusively high time resolution, with integration times of about 0.3 msec, which on the frequency scale corresponds to a cut-off frequency of 1700 Hz. This is more than an order of magnitude greater than the time resolution of hearing in terrestrial mammals. The frequency selectivity of hearing in cetaceans has been measured using several versions of the masking method. The acuity of frequency selectivity in cetaceans is several times greater than that in most terrestrial mammals (except bats). The acute frequency selectivity allows the discrimination of very fine spectral patterns of sound signals.

Potenciales evocados auditivos en pacientes que rechazan o no la amplificacion binaural

Se realizó un estudio descriptivo comparativo para determinar las diferencias significativas de los Potenciales Evocados Auditivos de Latencia Corta que podría, a través del análisis de diversas variables, determinar la razón por la cual los pacientes mayores de 65 años, con pérdida auditiva neurosensorial promedio hasta 70 – 80 dB rechazan la amplificación binaural en el Instituto Para Niños Ciegos y Sordos en la ciudad de Cali, en el 2005. Se tomó una muestra intencional de 40 pacientes con adaptación binaural de mínimo tres meses, de los cuales 20 rechazaban los audífonos y 20 no. El estudio permitió detectar que en los resultados de la latencia de las Onda I, III y V, las latencias interpicos I – III , III – V, I – V y la diferencia interaural de la onda V, utilizando un estímulo click, variando la velocidad del estímulo de 11 p/seg y 77 p/seg, y la polaridad del estímulo en Rarefacción y Condensación en cada uno de los oídos presentaron valores que no se desvían de lo normal, para la población objeto de estudio; igualmente esto sucedió en la funcionalidad auditiva en los dos grupos de pacientes en diferentes situaciones diarias presentadas en el cuestionario HHIE modificado. El estudio mostró que no existen diferencias significativas entre los dos grupos de estudio, lo cual se comprobó utilizando la prueba U de Mann-Whitney, es decir que la prueba electrofisiológica del BERA, no aporta información que permita determinar si un paciente mayor de 65 años con pérdida auditiva neurosensorial entre 70 y 80 dB se adaptará a la amplificación binaural.

Electrophysiological evidence for a defect in the processing of temporal sound patterns in multiple sclerosis

Objectives: To assess the processing of spectrotemporal sound patterns in multiple sclerosis by using auditory evoked potentials (AEPs) to complex harmonic tones. Methods: 22 patients with definite multiple sclerosis but...

Spectral Characteristics of Short-Latency Auditory Evoked Potentials in Neurological Diseases

A comparative study of the power spectra of short-latency auditory evoked potentials (SLAEPs) was made in norm and pathological states (neurinoma of the acoustic nerve, concussion of the brain, and epilepsy). Rather specific pattern of changes in the power of the medium- and high-frequency components along with the appearance of subcomponents was revealed. It is supposed that spectral analysis of SLAEP is highly informative and may be useful for neurophysiological clinical diagnostics.

Short-latency auditory evoked potentials during change in the physical parameter of a sound stimulus

The amplitude-temporal and spectral characteristics of the short-latency auditory evoked potentials (SLAEP) recorded under conditions of monoaural stimulation with sound clicks with initial phase of rarefaction followed by compression and alteration, with the intensity of 60 dB and frequency of 11.1 Hz, were studied in ipsi- and contralateral derivations. Substantial changes in SLAEP morphology in response to polarity inversion of the acoustic stimulus were found. Waves II, IV, VI, and VII changed to the greatest extent. The spectral analysis detected three main SLAEP components: low- (LF), medium- (MF), and high-frequency (HF) components as well as the respective frequency bands. Change in the click phase from rarefaction to compression resulted in bilateral redistribution of power between the MF and HF components. This was expressed as a decrease in the HF peak power and simultaneous rise of MF power. Selective effects of the polarity inversion of the sound stimulus on the MF and HF components support the finding that the activity of SLAEP-generating structures are mainly reflected in the mentioned components. It is suggested that two populations of phase-sensitive units are represented in the auditory analyzer. These populations determine the characteristic changes in SLAEP morphology and spectral characteristics.

Spectral characteristics of short latency auditory evoked potentials

Evoked potentials (EP) containing 15 components were recorded from the scalp surface in response to auditory stimulation. Short latency auditory evoked potentials (SLEP) represented seven early components occuring during 10-12 ms after the stimulation. Numerous electrophysiological studies of SLEP [2-1 !] have been carried out since the 1970s when Jevett [1] first described this type of evoked responses. However, many questions concerning the generation and propagation of particular SLEP components remained unanswered up until now. One of them concerns the frequency characteristics of SLEP. A study of this problem is quite important since spectral analysis of SLEP may yield knowledge about the new and more subtle parameters of this EP-type behavior under the change in experimental variables such as the polarity and intensity of the stimulus, the rate of its repetition, location of leads, and so on. Moreover, such studies might create prerequisites for extending the notions about EP generation mechanisms. It should be noted that just this aspect was practically neglected in the literature if not to speak about the two studies [12, 13], which did not fully use adequate spectral analysis technique with limited spectral power resolution and low accuracy of measuring the parameters of SLEP such as the range and peak values of the main frequency components.

Thresholds for Short-Latency Auditory-Evoked Potentials to Tones in Notched Noise in Normal-Hearing and Hearing-Impaired Subjects

The thresholds for the short-latency auditory evoked potentials (SLAEPs) to short-duration tones presented in notched-noise masking were evaluated in 20 normal-hearing and 20 hearing-impaired subjects. The differences (dB) between these thresholds (dB nHL) and the pure-tone behavioral thresholds (dB HL) across all 40 subjects were 11.6, 6.1, 6.3 and 0.8 dB for 500, 1,000, 2,000 and 4,000 Hz, respectively. These differences were significantly smaller for the hearing-impaired subjects than for the normal-hearing subjects. Ninety-eight percent of the SLAEP threshold estimations were within 30 dB of the subjects' pure-tone behavioral thresholds and 91% were within 20 dB.

Short-latency auditory evoked potentials in the monkey. I. Wave shape and surface topography

The components and topography of the short-latency auditory evoked potentials (SLAEPs) in the monkey were analyzed using a combination of surface and epidural electrodes. Nine positive peaks, and a slow negativity following wave 7, are identified in the SLAEP recorded at the vertex referred to the mastoid ipsilateral to a monaural stimulus. Subcomponents of waves 1 and 3 are consistently observed, and other waves are probably compound as well. Barbiturate anesthesia results in latency prolongations which are cumulative across components but does not alter the component sequence. With binaural stimulation there is simple summation of the monaural responses for the components preceding wave 7, but a binaural interaction for wave 7. The polarity and clarity of the various components depend on the recording configuration selected. No single configuration is optimal for the demonstration of all components, and the use of montages with multiple electrodes may increase the information gained from clinical SLAEP recordings in man. The monkey SLAEP components can be grouped based on similarities of their surface topographies, which suggest similar anatomic orientations of their underlying generators. Probable homologues between the components of the simian and human SLAEP, based on temporal sequence, topography, and the effects of variation of the stimulus parameters, are: Jewett's waves I through VII correspond to monkey waves 1, 3, and 5 through 9. Due to differences in the size and shape of the heads, the monkey waves 2 and 4 correspond to negativities in the human SLAEP, labeled IN and IIN after the components which they follow. Another peak, with latency between waves 7 and 8 in the monkey and V and VI in man, is only clearly seen in the mastoid-to-mastoid linkage, contralateral negative.

Short-latency auditory evoked potentials in the monkey. II. Intracranial generators

The generators of the short-latency auditory evoked potentials (SLAEPS) in the monkey have been defined by intracranial mapping from cochlea to auditory cortex. SLAEP components other than 1a and the slow negatively (SN) following wave 7 derive from compound action potentials propagated in subcortical auditory pathways. The component generators are complex due to the presence of two bursts of activity in the eighth nerve, to the fact that the ascending auditory fibers both synapse on and bypass specific relay nuclei, and to the differences in orientation of segments of the auditory pathways. Most SLAEP components recorded at the surface reflect the summation of activity from multiple generators. However, much of the activity seen within subcortical structures cannot be traced to the surface of the brain. Component 1a is identified with the cochlea summating potential, while 1b reflects the initial afferent volley in the distal portion of the eighth nerve. Component 2 represents the initial depolarization of the eighth nerve terminals within the ipsilateral cochlear nucleus. Component 3h reflects the second volley of activity in the distal portion of the eighth nerve and the outflow of the cochlear nucleus which decussates in the trapezoid body. Component 3v represents the initial cochlear nucleus outflow volley ascending the lateral lemniscus. Component 4 principally reflects the second volley activity within the eighth nerve terminals, and outflow from the ipsilateral superior olivary complex ascending in thet lateral lemniscus, with a possible contribution from activity in the contralateral CNC. Component 5 represents the outflow of the contralateral superior olivary complex ascending in that lateral lemniscus. Component 6 reflects another volley from the ipsilateral superior olivary complex ascending in that lateral lemniscus, as well as outflow from both inferior colliculi propagating in their brachii. The generators of components 7 are the most complex encountered, representing volleys in both lateral lemnisci, activity of the contralateral inferior colliculus, and activity in both auditory radiations. A component that follows wave 7, seen best in mastoid-to-mastoid recording linkage, represents outflow from both inferior colliculi propagating in their brachia. Components 8 and 9 principally reflect propagated action potentials in the auditory radiations bilaterally, with an additional contribution from activity of both inferior colliculi. The SN mainly represents volume-conducted postsynaptic potentials from both inferior colliculi and cochlear nuclei.