Three-dimensional planar and vector analysis of brainstem auditory evoked potentials as a function of intensity in guinea pig.

Brainstem auditory evoked potentials (BAEPs) have been studied in guinea pigs as a function of intensity by means of the Three-channel Lissajous' trajectory (3-CLT) method. Data were quantified in terms of duration, orientation of planar segments and orientation of equivalent dipoles. The auditory stimulus was a click varying from 48 dB pSPL to 108 dB pSPL by steps of 10 dB pSPL.

[Comparative study by computerized EEG of dementia of the ALzheimer type and Parkinson's disease with dementia].

A computerized EEG (cEEG) study was performed in two groups of patients with dementia of the Alzheimer type (DAT) and with Parkinson's disease with dementia (PDD). Compared to control subjects suffering from Parkinson's disease without dementia, both groups demonstrated similar slowing down of background activity. However, there were more low frequency components, defined as between 2.

Wave III of brain-stem auditory evoked potentials analysed both with 3-channel Lissajous' trajectory and dipole localization method.

Wave III of the BAEP was analysed both with 3-channel Lissajous' trajectory (3-CLT) and a dipole localization method. The experiments were performed on 5 normally hearing subjects. The dipole analysis used an iterative algorithm assuming a spherical head model and homogeneous media.

Same location of the source of P1 of BAEPs and N1 of CAP in guinea pig.

The purpose of this study was to point out the location of N1 and N2 of the compound action potential (CAP) and the first waves of the brainstem auditory evoked potentials (BAEPs) by the mean of the section of the eighth nerve at the porus acousticus in guinea pigs. Our results agree with most of the studies in the literature. In the absence of lesion of the internal auditory artery, the section of the cochlear nerve induced the persistence, alone, of the P1 of BAEPs in which latency was similar to initial P1 before section, and the subsequent waves disappeared.

Microcomputer analysis of three-channel Lissajous' trajectory of auditory brainstem evoked potentials.

A software package for the IBM PC computer is presented to facilitate the analysis of three-channel Lissajous' trajectories (3CLT) of auditory brainstem potentials. The program deals with 4-channel numeric or ASCII files, including three orthogonal X, Y, Z channels and standard vertex-mastoid on the stimulated side. The 3CLT analysis program implements standard measurements of peak latencies, voltage amplitude and curvature plots computed from the three orthogonal channels, interactive three-dimensional rotations of the trajectory and planar segment analysis.

[Auditory evoked potentials of the brain stem in brain death].

Brainstem auditory evoked responses were recorded in a neurosurgical intensive care unit in 38 patients who had all the clinical criteria for brain death. Of the brain-dead patients, 65.8% never showed a response.

Effects of electrolytic lesions of the superior olivary complex and trapezoid body on brainstem auditory-evoked potentials in the guinea pig. II. Three-channel Lissajous' trajectory analysis.

Brainstem auditory-evoked potentials (BAEP) were studied both with vertex (positive) - tragus (negative) derivation and three-channel Lissajous' trajectory (3-CLT) planar analysis in guinea pigs (GP) after destruction of the ipsilateral superior olivary complex (SOC) (6 GP), contralateral SOC (8 GP) referred to the stimulation side, and trapezoid body (TB) in the sagittal line (8 GP). The size of the lesion was evaluated on histological examination. The right ear was locally destroyed with aminoside instillation.

[Characteristics of 3-dimensional representations of brain stem auditory evoked potentials].

The three dimensional Lissajous curves (3 CLT) of orthogonal derivation (vertex Z+; throat Z-) (left mastoïd Y+; right mastoïd Y-) (nasion X+; neck X-) were calculated and recorded by a computer. 3-D curves were computed with an apparent rotation around the vertical axis Z. Through successive exhibition of the "virtual" plots, the observer will remark a spatial representation of the 3-D curve.

Digitization of electrophysiological documents.

The mechanism presented in this paper is devoted to the transfer of paper documents as electrophysiological records into 'electronic documents' for direct storage and analysis by a computer.

Three-dimensional curves: main parameters of brainstem auditory-evoked responses in the normal subject.

Brainstem evoked potentials (BER) have been studied in three dimensions (3D). It was necessary to record simultaneously three orthogonal derivations in the three spatial axes. The 3D curves obtained were formed by successive uncompletely locked loops which correspond with the first five waves of BER.

[Sodium gamma-hydroxybutyrate. Effects on visual flash-evoked potentials].

Na gamma hydroxybutyrate being recognized as a mean of brain protection, the effect of Na gamma hydroxybutyrate on visual evoked potentials is studied in ten neurosurgical patients. Recordings are made in the same intensive care unit and with the same equipment. Latencies of the three principal peaks (III, IV, V) are analysed.

Impairment of memorization by high doses of pyridoxine in man.

Two controlled trials were performed successively to evaluate the effect of high doses of oral pyridoxine on brain performance in man. In trial I, medical students volunteered to take 100 mg, 500 mg of pyridoxine a day or placebo for 10 days. A digit coding test was performed before, and at the end of the treatment period and a third 15 days later.

[A method for recording auditory evoked brain stem responses for use with objective audiometry and in neurology (author's transl)].

After defining the auditory evoked brain stem responses, the authors discuss the importance of the recording conditions and their influence on the recorded response. The choice of leads, frequency of stimulus repetition and strength of stimulus are all modifying factors. In objective audiometry it seemed preeferable to choose the technical conditions which would highlight wave V, which is identifiable even with stimuli close to threshold.