A Polyakov

Technion - Israel Institute of Technology, H̱efa, Haifa District, Israel

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Publications (20)21.75 Total impact

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    ABSTRACT: Subjects with brainstem lesions due to either an infarct or multiple sclerosis (MS) underwent two types of binaural testing (lateralization testing and interaural discrimination) for three types of sounds (clicks and high and low frequency narrow-band noise) with two kinds of interaural differences (level and time). Two major types of abnormalities were revealed in the lateralization performances: perception of all stimuli, regardless of interaural differences (time and/or level) in the center of the head (center-oriented), or lateralization of all stimuli to one side or the other of the head (side-oriented). Similar patterns of abnormal lateralization (center-oriented and side-oriented) occurred for MS and stroke patients. A subject's pattern of abnormal lateralization testing was the same regardless of the type of stimulus or type of interaural disparity. Lateralization testing was a more sensitive test than interaural discrimination testing for both types of subjects. Magnetic resonance image (MRI) scanning in three orthogonal planes of the brainstem was used to detect lesions. A semi-automated algorithm superimposed the auditory pathway onto each MRI section. Whenever a lesion overlapped the auditory pathway, some binaural performance was abnormal and vice versa. Given a lateralization test abnormality, whether the pattern was center-oriented or side-oriented was mainly determined by lesion site. Center-oriented performance was principally associated with caudal pontine lesions and side-oriented performance with lesions rostral to the superior olivary complex. For lesions restricted to the lateral lemniscus and/or inferior colliculus, whether unilateral or bilateral, just noticeable differences (JNDs) were nearly always abnormal, but for caudal pontine lesions JNDs could be normal or abnormal. MS subjects were more sensitive to interaural time delays than interaural level differences particularly for caudal pontine lesions, while stroke patients showed no differential sensitivity to the two kinds of interaural differences. These results suggest that neural processing of binaural stimuli is multilevel and begins with independent interaural time and level analyzers in the caudal pons.
    Hearing Research 06/2000; 143(1-2):29-42. · 2.54 Impact Factor
  • H Pratt, A Polyakov
    Electroencephalography and clinical neurophysiology. Supplement 02/1999; 50:235-42.
  • A Polyakov, H Pratt
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    ABSTRACT: The purpose of this study was to determine the contribution of click frequency bands (broad-band, >2000 Hz, <2000 Hz and <1000 Hz) to binaural interaction components (BICs) of the human auditory brainstem evoked potentials (ABEPs). The human BICs were studied by subtracting the potentials to binaural clicks from the algebraic sum of monaurally evoked potentials to either ear. Effective frequency bands were derived using clicks alone or clicks with ipsilateral or binaural masking noise, high- or low-pass filtered at different cut-off frequencies. Analysis included single-channel vertex-cervical spinous process VII derivation of BIC and ABEP, as well as estimating the single, centrally located dipole equivalent of the surface activity from three orthogonally positioned electrode pairs, using the three-channel Lissajous' trajectory (3-CLT) analysis. All BIC 3-CLTs included three major components (labeled BdII, BeI, and BeII) approximately corresponding in latency to IIIn, V and VI ABEP peaks. All apex latencies of BIC 3-CLT, except BeI, were longer in response to <2000 Hz and <1000 Hz (low-frequency) effective clicks. Apex amplitude of components BeI and BeII of BIC 3-CLT were smaller with low-frequency effective clicks than with broad-band or high-frequency (>2000 Hz) clicks. We suggest that binaural interaction component BeI is mainly tuned to high frequencies, showing no frequency effect on latency, and decreasing in amplitude with decreasing click high frequency content. In contrast, BdII and BeII of the human BICs are evoked more synchronously by high-frequency binaural inputs, but are also sensitive to low frequencies, increasing in latency according to the cochleotopic activation pattern. These differences between BIC components may reflect their roles in sound localization.
    Audiology: official organ of the International Society of Audiology 01/1999; 38(6):321-7.
  • A Polyakov, H Pratt, Y Shi
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    ABSTRACT: Auditory brain-stem evoked potentials (ABEPs) were recorded from 10 normal hearing subjects in response to rarefaction clicks, presented at a rate of 11/s. Stimuli were binaurally symmetrical and isochronic at 75 dB peSPL or with interaural time disparities (ITDs) of +/-0.4 ms, or intensity disparities (IIDs) of +/-10 dB. Potentials were recorded from vertex-neck, as well as from 3 orthonormally positioned differential derivations. The amplified potentials were averaged over 8000 repetitions using a dwell time of 20 micros/address/channel. The effects of contralateral stimulation on neural responses of the peripheral auditory system were obtained by subtracting the binaural response from the algebraic sum of responses to left and right monaural stimuli. From the 3 orthonormal derivations, 3-channel Lissajous' trajectories (3-CLTs) to the various stimulus conditions and difference waveforms were derived. The results corroborated earlier studies on binaural interaction components (BICs), which include 3 major components corresponding in latency to the vertex-mastoid peaks IV-VI of ABEP. In addition, the binaural difference waveforms included 3 earlier, low-amplitude components. Latency correspondence and comparison of difference waveform and ABEP 3-CLTs indicated that the first and third early difference waveform components corresponded to the negative peaks following I and III, respectively, of the vertex-neck ABEP to binaural clicks. These results indicate that early ABEP peaks, generated peripheral to binaural convergence, may be affected by contralateral stimulation. These contralateral effects were in a pattern compatible with suppression. most probably by efferents of the olivo-cochlear bundle.
    Electroencephalography and Clinical Neurophysiology 12/1998; 108(6):543-53.
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    ABSTRACT: Four sets of measurements were obtained from 11 patients (44-80 years old) with small, localized pontine lesions due to vascular disease: (1) Monaural auditory brain-stem evoked potentials (ABEPs; peaks I to VI); (2) Binaural ABEPs processed for their binaural interaction components (BICs) in the latency range of peaks IV to VI; (3) magnetic resonance imaging (MRI) of the brain-stem; and (4) psychoacoustics of interaural time disparity measures of binaural localization. ABEPs and BICs were analyzed for peak latencies and interpeak latency differences. Three-channel Lissajous' trajectories (3-CLTs) were derived for ABEPs and BICs and the latencies and orientations of the equivalent dipoles of ABEP and BICs were inferred from them. Intercomponent latency measures of monaurally evoked ABEPs were abnormal in only 3 of the 11 patients. Consistent correlations between sites of lesion and neurophysiological abnormality were obtained in 9 of the 11 patients using 3-CLT measures of BICs. Six of the 11 patients had absence of one or more BIC components. Seven of the 11 had BICs orientation abnormality and 3 had latency abnormalities. Trapezoid body (TB) lesions (6 patients) were associated with an absent (two patients with ventral-caudal lesions) or abnormal (one patient with ventral-rostral lesions) dipole orientation of the first component (at the time of ABEPs IV), and sparing of this component with midline ventral TB lesions (two patients). A deviant orientation of the second BICs component (at the time of ABEPs V) was observed with ventral TB lesions. Psychoacoustic lateralization in these patients was biased toward the center. Rostral lateral lemniscus (LL) lesions (3 patients) were associated with absent (one patient) or abnormal (two patients) orientation of the third BICs component (at the time of ABEPs VI); and a side-biased lateralization with behavioral testing. These results indicate that: (1) the BICs component occurring at the time of ABEPs peak IV is dependent on ventral-caudal TB integrity; (2) the ventral TB contributes to the BICs component at the time of ABEPs peak V; and (3) the rostral LL is a contributing generator of the BICs component occurring at the time of ABEP peak VI.
    Electroencephalography and Clinical Neurophysiology 10/1998; 108(5):511-20.
  • A Polyakov, H Pratt
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    ABSTRACT: The purpose of this study was to compare the effects of monaural and binaural broadband masking noise on binaural interaction components (BICs) of the human auditory brain stem evoked potentials (ABEPs). The BICs of the human ABEPs were studied by subtracting the potentials to binaural clicks from the algebraic sum of monaurally evoked potentials to clicks alone or to clicks with ipsilateral monaural or binaural broadband masking noise. Alternating polarity, 11/sec clicks were presented at 65 dB nHL, and noise was presented at 45 dB nHL. Analysis included peak-to-prestimulus baseline amplitudes and latencies of BICs' peaks and troughs from the vertex-mastoid (A) and vertex-neck (Z) channels. In addition, 3-channel Lissajous' trajectory (3-CLT) analysis, estimating the single, centrally located dipole equivalent of surface activity, was performed on data recorded from three orthogonally positioned electrode pairs. 3-CLT measures included apex latency, amplitude, and orientation, as well as planar segment duration, size, shape, and orientation. All BICs 3-CLTs included five main components (labeled BdI, BdII, BdIII, BeI, and BeII). In general, apex latencies were longer with masking noise. However, BdII and BeI apex latencies were shorter with binaural than with ipsilateral monaural masking noise. Apex amplitude and planar segment size of component BeI, as well as P1 peak amplitude in BICs of the Z-channel records, were larger with binaural than with monaural noise. No significant difference between the monaural and binaural noise conditions was found in durations, shapes, and orientations of planar segments of BICs 3-CLT, nor in peak latency of BICs in the A- and Z-channel records. We suggest that these effects on the latency and amplitude of BICs reflect binaural processing in the human brain stem. In particular, the larger amplitudes and shorter latencies of P1 and BeI with binaural than with ipsilateral monaural masking may be associated with the psychophysical effect of binaural masking level difference.
    Ear and Hearing 07/1998; 19(3):232-9. · 3.26 Impact Factor
  • H Pratt, Y Shi, A Polyakov
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    ABSTRACT: Contralaterally evoked transient otoacoustic emissions (CETOAEs) were recorded from 10 normal-hearing young adults (20 ears) in response to monaural, 11/s, 65 dB pe SPL clicks to the ear contralateral to the microphone probe. A burst of CETOAEs was observed 12-22 ms (average peak at 18.5 ms) after the contralateral click, and its mean level was -7.3 dB pe SPL, 4 dB above the averaged noise level. The frequency content of CETOAEs included a prominence around 1 kHz. In 40% of the ears examined CETOAEs were 3 dB or more above noise level in both replications of records from the same ear. To explain these results CETOAEs are suggested to reflect mechanical events induced by the crossed efferent system in the cochlea that was contralateral to the stimulated ear. The latency of the contralateral responses suggests that they may be related to the contralateral suppression effect observed with binaural stimulation. The latency of the response, coupled with the anatomical origin of the crossed efferent system at the superior olivary complex, suggest its involvement in the contralateral CETOAEs reported here.
    Hearing Research 02/1998; 115(1-2):39-44. · 2.54 Impact Factor
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    A Polyakov, H Pratt
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    ABSTRACT: The binaural interaction components (BIC) of the human auditory brainstem responses have been associated with sound lateralization which involves analyzing correlated inputs from the two ears. To test the hypothesis that BIC generators are specifically sensitive to binaural, correlated sounds, the effects of monaural and binaural correlated and uncorrelated masking on BIC to clicks were compared. Analysis included peak-to-prestimulus baseline amplitudes and latencies of BIC peaks from the vertex-mastoid ('A') and vertex-neck ('Z') channels, as well as the three-channel Lissajous trajectory (3-CLT) measures. Trajectory amplitudes of BIC BdIII, BeI and BeII were significantly suppressed by correlated (but not by uncorrelated) binaural noise, when compared with the unmasked condition. Moreover, component BdIII was more affected by masking with correlated than with uncorrelated binaural noise. Overall, binaural noise was more effective in suppressing BIC then monaural noise, and interaurally correlated binaural noise was more effective than uncorrelated binaural noise. These results are compatible with BIC generation by a binaurally activated subset of central auditory neurones which is sensitive to interaurally correlated sounds. Such a subset has been associated with the superior olivary complex and is assumed to be involved in sound lateralization.
    Audiology: official organ of the International Society of Audiology 01/1998; 37(1):17-26.
  • Y Shi, A Polyakov, H Pratt
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    ABSTRACT: Monaural and binaural 11/s, 65 dB pe SPL clicks with interaural time and intensity disparities known to affect central auditory processing were used to study contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in 10 subjects (20 ears). Psychophysical assessment of sound lateralization induced by the same stimuli was also conducted. TEOAEs were recorded to monaural (ipsilateral to the OAE recording probe) and to binaural clicks when clicks to the contralateral ear were synchronous and symmetrical in intensity, or, in the binaural intensity disparity conditions, synchronous but 10 dB higher or 10 dB lower in the ear contralateral to the OAE recording probe. When interaural time disparities were studied, the clicks to the contralateral ear were of the same intensity throughout, but 400 micros earlier or 400 micros later than to the ear with the probe. The TEOAE components at 13-15.8 ms showed suppression, relative to monaural responses, under all binaural conditions. This contralateral suppression did not correlate with the psychophysical findings. Suppression effects were more pronounced with binaural disparity than with binaurally symmetrical clicks. Thus, although contralateral click intensity was the same with time disparities, suppression was paradoxically enhanced compared to the binaurally symmetrical stimulation. To explain these results we propose that two factors are involved in TEOAE suppression with binaural clicks: (1) contralateral intensity and (2) interaural disparity (time or intensity). The latency of the suppressions observed, the effect of interaural disparity on these suppressions, coupled with the anatomical origin of the crossed efferent fibers and the disparity sensitivity of the superior olivary complex (SOC), all suggest SOC involvement in these TEOAE suppressions.
    Hearing Research 09/1997; 110(1-2):259-65. · 2.54 Impact Factor
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    H Pratt, A Polyakov, L Kontorovich
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    ABSTRACT: Sound lateralization can be induced by interaural intensity disparities (IIDs) or by interaural temporal disparities (ITDs). The purpose of this study was to indicate whether IIDs and ITDs are processed by the same central units that detect interaural disparity in timing of afferent activity. If sound lateralization to intensity and time cues was determined by the same afferent latency disparity detectors in the brainstem, lateralization would be the same, regardless of whether latency disparity was induced by IIDs or ITDs. Moreover, the disparity detectors, and thus their dipole equivalents, would be the same for equal lateralizations, whether induced by IIDs or ITDs. Auditory brainstem evoked potentials (ABEPs) were recorded in response to monaural and binaural clicks, with a variety of IIDs and ITDs. Peak II (proximal auditory nerve activity), peak III (input to the superior olivary complex), and binaural interaction components (BICs) BeI and BeII (binaurally activated upper pons) were identified and their latencies measured. The psychophysical lateralization of the clicks (in cm from vertex) was also measured in response to the same binaural stimuli. The correlations between interaural afferent latency disparities (difference in corresponding peak latencies originating in each ear) and psychophysical click lateralization were calculated. Similarly, the correlations with click lateralization of the BICs equivalent dipole latency as well as orientation change (relative to symmetrical clicks) were determined. A strong correlation with lateralization was found for peaks II and III latency disparities, with steeper slopes for IIDs than for ITDs. Moreover, binaural activity across the same lateralizations differed between IIDs and ITDs. These results, therefore, indicate that interaural time and intensity cues are processed by separate systems in the brainstem, both at the afferent convergence level and after interaural disparities are determined.
    Hearing Research 07/1997; 108(1-2):1-8. · 2.54 Impact Factor
  • A Polyakov, H Pratt
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    ABSTRACT: Three-channel Lissajous' trajectories (3-CLT) of the binaural interaction (BI) in auditory brainstem evoked potentials (ABEP) were derived from 13 normally and symmetrically hearing adults by subtracting the response to binaural clicks from the algebraic sum of monaural responses. ABEPs were recorded from four channels, three of them orthonormal to each other, in response to alternating polarity clicks, presented at a rate of 11/s with interaural time differences (ITD) of 0.2, 0.4 and 1.0 ms and an intensity of 65 dB nHL, or isochronic to both ears with interaural intensity differences (IIDs) of 5, 10 and 15 dB (65 dB nHL +/- 2.5, 5.0 and 7.5 dB, respectively). All 3-CLTs included 6 planar segments (labeled BdI, BdII, BdIII, BeI, BeII and Bf). Amplitudes of 3-CLT BI components were not significantly affected by increasing ITDs and IIDs, but latencies of all components increased significantly. The most remarkable finding was a significant change in apex orientations of BeI and BeII of the BI 3-CLT across stimulus conditions. The changes in BeI and BeII apex orientations, across stimulus conditions, may reflect differences in the anatomical representation of activity evoked by differently lateralized sounds. We suggest that this may indicate spatio-topic organization in the human brainstem.
    Hearing Research 06/1996; 94(1-2):107-15. · 2.54 Impact Factor
  • H Pratt, A Polyakov
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    ABSTRACT: The binaural interaction components of auditory brainstem evoked potentials reflect electrical changes which are specific to binaural stimuli. Analysis of these components indicated that different click lateralizations result in spatially distinct distributions of activity in the pons, but not at more peripheral levels. The effects of ipsilateral and binaural masking on evoked activity indicated distinct binaurally- and monaurally-activated neural subsets in the human brainstem. These results on the effects of noise and the distinct distributions of pontine activity to different lateralizations provide the first electrophysiological evidence that the auditory system in the humans pons includes a subset which is specific to binaurally presented sounds and which is anatomically distributed according to the lateralization of the sound. These results suggest auditory spatial mapping, similar to other sensory systems. In contrast to other systems, in which mapping is according to receptor distribution in the periphery, auditory spatial mapping is achieved computationally at central levels of the pathway.
    Journal of basic and clinical physiology and pharmacology 02/1996; 7(3):235-44.
  • A. Polyakov, H. Pratt
    Electroencephalography and Clinical Neurophysiology 01/1996; 99(2).
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    ABSTRACT: The role of the auditory brainstem in tinnitus is questionable. This study aimed comprehensively to assess auditory brainstem responses (ABRs) in patients suffering from noise-induced tinnitus (NIT). ABRs were recorded from 13 chronic NIT patients (21 ears) and 11 (21 ears) age and hearing matched control subjects without tinnitus. ABRs were recorded with scalp electrodes placed ipsilateral and contralateral to the stimulated ear, and in three orthonormal differential configurations. The ABRs were analyzed as a function of time, frequency and voltage space. A significantly enhanced ipsilaterally recorded, time domain wave III amplitude was observed for the tinnitus patients. This finding was not confirmed by any of the other ABR measures, which were indistinguishable between subject groups. Although this may be a spurious result, it nonetheless may point to an alteration in the functioning of the putative wave III auditory brainstem generator, which deserves further study.
    Audiology: official organ of the International Society of Audiology 01/1996; 35(5):259-70.
  • Polyakov A, Pratt H
    Electroencephalography and Clinical Neurophysiology 08/1995; 95(3):77P-77P.
  • A Polyakov, H Pratt
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    ABSTRACT: Three-channel Lissajous' trajectories (3-CLTs) of the binaural interaction component (BI) of auditory middle latency evoked potentials (AMLEPs) were derived from 14 normally hearing adults by subtracting the response to binaural clicks from the algebraic sum of monaural responses. AMLEPs were recorded in response to 65 dB nHL, rarefaction clicks, presented at a rate of 3.3/s. A normative set of BI 3-CLT measures was calculated and compared with the corresponding measures of simultaneously recorded, single-channel vertex-left mastoid and vertex-neck derivations of BI and of AMLEP to binaural stimulation (B). 3-CLT measures included: apex latency, amplitude and orientation, as well as planar segment duration, orientation, size and shape. The results showed seven main apices and associated planar segments ('Be', 'Bf', 'Bg', 'Bh', 'Bi1', 'Bi2' and 'Bj') in the 3-CLT of BI. Apex latencies of the BI 3-CLT were comparable to peak latencies of the vertex-left mastoid and vertex-neck AMLEP and BI records, both in their absolute values and in intersubject variability. Durations of BI planar segments were approximately 5.0 ms. Apex amplitudes of BI 3-CLT were larger than the respective peak amplitudes of the vertex-mastoid and vertex-neck BI records, while their intersubject variabilities were comparable. The lateralization of BI components may indicate asymmetric processing of binaural auditory input, or may be connected with anatomical asymmetry such as skull thickness. Preliminary analyses did not reveal a clear correlation between the lateralization of the BI component 'Bi2' and the handedness of the subject. We suggest that BI components of AMLEP may be associated with the primary auditory cortex and subcortical ascending structures.
    Hearing Research 03/1995; 82(2):205-15. · 2.54 Impact Factor
  • A Polyakov, H Pratt
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    ABSTRACT: Three-channel Lissajous trajectories (3-CLTs) of binaural interaction components (BI) of auditory brainstem potentials (ABEPs) were derived from 13 normally hearing adults by subtracting the response to binaural clicks from the algebraic sum of monaurally evoked responses to clicks. ABEPs were recorded in response to 65 dB nHL, alternating-polarity clicks, presented at a rate of 11/s. The procedure was repeated with clicks alone as well as with clicks with broad-band masking noise. Noise was presented at 25 and 45 dB nHL, producing a signal-to-noise ratio of +40 and +20 dB, respectively. All BI 3-CLTs included 6 planar segments (labeled BdI, BdII, BdIII, BeI, BeII and Bf) whose apex latencies, except Bf, increased with increasing noise level above 25 dB nHL, and whose durations, sizes, shapes and orientations did not change across noise levels. There were also significant increases in peak latencies of the BI from single channels vertex-mastoid and vertex-neck with increasing noise level. No significant change was found in the trajectory amplitude of apices, with the exception of apices BdIII and Bf whose amplitudes increased with increasing noise level. We suggest that the paradoxical increase in BI amplitude with masking noise may reflect a binaural enhancement of the effect of noise. The effects observed indicate that, whereas the response to clicks displays occlusion, the response to noise displays spatial facilitation at the brainstem level.
    Audiology: official organ of the International Society of Audiology 01/1995; 34(1):36-46.
  • A Polyakov, H Pratt
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    ABSTRACT: We provide the normative values for middle latency auditory evoked potentials (MLAEPs) measures (three-channel Lissajous' trajectories or 3-CLT) in response to clicks and tone pips, which are the stimuli most widely used in MLAEP clinical testing. The relationship of 3-CLT measures to the more widely used latency and amplitude characteristics of the single-channel MLAEP of the same subjects was also evaluated. We further relate the 3-CLT findings to the question of MLAEP generators. 3-CLT of MLAEPs were derived from 12 humans (24 ears) in response to 65 dB nHL, rarefaction clicks as well as tone pips (1000 Hz), presented at a rate of 3.3/sec. A normative set of 3-CLT measures was calculated and compared with the corresponding measures of simultaneously recorded, single-channel vertex-left mastoid and vertex-neck derivation of MLAEP. Apex latencies of 3-CLT were comparable to peak latencies of the vertex-neck record, both in absolute values and in intersubject variability. Durations of planar segments were approximately 5.0 msec. Size and shape measures of planar segments were variable across subjects, making their clinical use, in their present form, questionable. The results showed two apices and associated planar segments (i1 and i2) in the 3-CLT of MLAEP which corresponded to the vertex-neck component Pa. These results and earlier studies that indicated a dual set of generators for Pa are compatible with a primary auditory cortex generator for i1 and ascending subcortical generators for i2.
    Ear and Hearing 11/1994; 15(5):390-9. · 3.26 Impact Factor
  • A Polyakov, H Pratt
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    ABSTRACT: The 3-channel Lissajous' trajectory (3-CLT) of the binaural interaction components (BI) in auditory brain-stem evoked potentials (ABEPs) was derived from 17 normally hearing adults by subtracting the response to binaural clicks (B) from the algebraic sum of monaural responses (L + R). ABEPs were recorded in response to 65 dB nHL, alternating polarity clicks, presented at a rate of 11/sec. A normative set of BI 3-CLT measures was calculated and compared with the corresponding measures of simultaneously recorded, single-channel vertex-left mastoid and vertex-neck derivations of BI and of ABEP L + R and B. 3-CLT measures included: apex latency, amplitude and orientation, as well as planar segment duration and orientation. The results showed 3 apices and associated planar segments ("BdII," "Be" and "Bf") in the 3-CLT of BI which corresponded in latency to the vertex-mastoid and vertex-neck peaks IIIn, V and VI of ABEP L + R and B. These apices corresponded in latency and orientation to apices of the 3-CLT of ABEP L + R and ABEP B. This correspondence suggests generators of the BI components between the trapezoid body and the inferior colliculus output. Durations of BI planar segments were approximately 1.0 msec. Apex amplitudes of BI 3-CLT were larger than the respective peak amplitudes of the vertex-mastoid and vertex-neck recorded BI, while their intersubject variabilities were comparable.
    Electroencephalography and Clinical Neurophysiology 10/1994; 92(5):396-404.
  • A Polyakov, H Pratt
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    ABSTRACT: Three-channel Lissajous trajectories (3-CLTs) of the binaural interaction components of the auditory brainstem-evoked potentials were recorded from 17 adult subjects in response to rarefaction, condensation and alternating polarity clicks. All 3-CLTs included 3 planar segments (named Bd, Be and Bf) whose latencies, amplitudes, orientations, sizes and shapes were not affected by click polarity. A significant increase was found in the duration of planar segment Be to alternating polarity clicks. This effect may be explained by limitations of spatiotemporal resolution of the method, which did not allow distinction of contributions from temporally overlapping generators participating in binaural processing.
    Audiology: official organ of the International Society of Audiology 01/1994; 33(5):264-73.