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Results for “Brain Mapping”

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PubMed1993

Findings of electroencephalographic brain mapping in mild to moderate dementia of the Alzheimer type during resting, motor, and music-perception conditions.

Sixteen-channel electroencephalographic (EEG) brain mapping studies were carried out under resting conditions in 41 patients with mild to moderate dementia of the Alzheimer type, diagnosed according to DSM-III-R criteria. The patients showed diffuse patterns of EEG slowing, as known from the literature. They showed increases of theta power in large bilateral brain areas and bitemporal increases of delta power as compared with both age-matched and younger control subjects. In addition, the patients had increased beta activity in comparison with the younger control group, but not with the age-matched control subjects. Functional brain mapping revealed decreases of EEG power during manual-motor and music-perception tasks in delta frequencies for patients, which was not seen in either of the two control groups. All frequency bands revealed major gender-related differences in EEG activity, which should receive more attention in future research.

Aged↗

PubMed1992

[Brain mapping in atonic epileptic attacks with consciousness disorders at school age].

The paper presents the results of the analysis of atonic epileptic seizures with application of brain mapping eeg. The views to date on the pathogenesis of atonic seizures could be based on the assumptions of centrencephalic epilepsy voiced by Penfield and Jasper. The present investigations and electrophysiological-clinical observations support, however, contrary to the concept of Penfield and Jasper, the cortical origin of these seizures. The discussion on the clinical forms of atonic seizures in epilepsy, confirmed by analysis of brain mapping in the domain of frequencies and amplitude distribution, in the form of brain topograms, allows for the concept of cortical origin of these seizures with the probability of localisation of the epileptic focus, as in here presented case, in the anterior right paramedial frontal region of the brain.

Adolescent↗

PubMed1983

The development and evaluation of a low-cost microdensitometer for use with the 2-deoxy-D-glucose method of functional brain mapping.

The conversion of a standard laboratory compound microscope into a microdensitometer for use in the 2-deoxy-D-glucose autoradiographic method of functional mapping in the brain is described. A solid-state detector was attached to the camera port of a Zeiss Universal Microscope and minor modifications to the microscope optics were made to produce a microdensitometer with a field of view 0.15 mm in diameter. Details are presented showing the modifications to the microscope which do not permanently destroy its functional ability to perform as a viewing microscope. A simple electronic circuit is presented to digitally display the output of the photo detector. Calibration of the instrument in terms of optical density or 2-deoxy-D-glucose activity is also described. The primary design goal was the construction of a simple, reliable, inexpensive microdensitometer that could be assembled by laboratory personnel. This densitometer should allow laboratories on modest budgets to have access to quantitative methods for the study of brain functional activity at a cost considerably less than the price of a commercial microdensitometer.

Animals↗

PubMed1992

Toward a brain map of auditory hallucinations.

OBJECTIVE: This study asks whether auditory hallucinations are reflected in a distinctive metabolic map of the brain. METHOD: Regional brain metabolism was measured by positron emission tomography with [18F]-fluorodeoxyglucose in 12 DSM-III schizophrenic patients who experienced auditory hallucinations during glucose uptake and 10 who did not. All patients were free of neuroleptics and 19 had never been treated with neuroleptics. Nine patients were reexamined after 1 year to assess effects of neuroleptic treatment. RESULTS: Compared with the patients who did not experience hallucinations, the patients who did experience hallucinations had significantly lower relative metabolism in auditory and Wernicke's regions and a trend toward higher metabolism in the right hemisphere homologue of Broca's region. Hallucination scores correlated positively and significantly with relative metabolism in the striatum and anterior cingulate regions. Neuroleptic treatment resulted in a significant increase in striatal metabolism and a reduced frontal-parietal ratio, which was significantly correlated with a decrease in hallucination scores. CONCLUSIONS: Auditory hallucinations involve language regions of the cortex in a pattern similar to that seen in normal subjects listening to their own voices but different in that left prefrontal regions are not activated. The striatum plays a critical role in auditory hallucinations.

Adult↗

PubMed1989

Topographic EEG brain mapping in cerebrovascular disease and dementia.

1. The results of brain mapping had been studied in 27 patients with different stages of ischemic stroke and in 20 patients with dementia, ten of SDAT and ten of vascular type. 2. It has been shown that in ischemic stroke the mapping correlates better with the severity of clinical symptoms than with anatomical and hemodynamic imaging methods. For the differentiation of SDAT and VD the mapping showed a clear cut possibility of differentiation.

Aged↗

PubMed1992

Functional brain mapping using magnetic resonance imaging. Signal changes accompanying visual stimulation.

Easily detectable (5%-20%) transient increases in the intensity of water proton magnetic resonance (MR) signals in human primary visual cortex were observed during visual stimulation in gradient echo images at 4-T field strength. The signal intensity increases were predominantly restricted to areas containing gray matter and were used to produce high-spatial-resolution human functional brain maps. Time dependence of the functional brain maps also was monitored during visual stimulation using images acquired every approximately 5 seconds; these images with high spatial and temporal resolution demonstrated that photic stimulation first resulted in signal increases in a large area of the visual cortex followed by a reduction in the size of the area, and that signal intensity increases in the gray matter were time dependent. Reducing the image acquisition echo times reduced the amplitude of the fractional signal change, suggesting that it is produced by a change in T2 or T2*. The amplitude, sign, and echo time dependence of these intrinsic signal changes are consistent with the idea that neural activation increases regional cerebral with the idea that neural activation increases regional cerebral blood flow (rCBF) with a concomitant increase in venous blood oxygenation.

Brain Mapping↗

PubMed1987

Topographic brain mapping of EEG in neuropsychopharmacology--Part I. Methodological aspects.

Topographic brain mapping of the electroencephalogram (EEG) is a promising new method in neuropsychiatry and neuropsychopharmacology. Rapid advances in computer technology allow on-line analysis by means of micro-computers. This paper describes an acquisition and signal analysis system for studying neurophysiological and neuropsychopharmacological aspects of human brain function. It consists of a server micro-computer functioning as an acquisition unit which is connected to a workstation micro-computer for statistical analysis and subsequent documentation of data on a printer and color plotter. According to the recommendations for standardization of data acquisition and signal analysis in pharmaco-electroencephalography, the paper mediates detailed information concerning recording and analysis equipment with special emphasis on the treatment of artifacts. Since up to now there is no normative consensus on the choice of reference conventions and interpolation algorithms, the system is designed for high flexibility to enable empirical comparisons between different methods.

Brain↗

PubMed1992

Study of the P300 event-related potential through brain mapping in phonological dyslexics.

The auditory P300 was studied through brain mapping in 10 phonological dyslexics (7 M and 3 F), who were found to differ significantly from normals in presenting a longer P300 latency and smaller amplitude on the N2-P3 wave. Interesting too was the asymmetry of the P300 distribution between the two hemispheres, with less amplitude on the right. These findings confirm the hypothesis of reduced right hemisphere functioning during the process of information analysis in phonological dyslexics.

Attention↗

PubMed2000

Reconstruction of electroncephalogram brain maps by incorporating the blind source separation concept.

Electroencephalogram (EEG) brain maps provide useful and reliable neurodiagnostic information. Accurate reconstruction of the data requires an efficient separation of the electrode signals. Although autoregressive (AR) spectrum estimation highly refines the signals, it cannot remove the effect of adjacent electrode signals. This report describes an efficient blind signal separation (BSS) method. The algorithm identifies the coefficients of an adaptive FIR filter by minimization of a cost function in terms of the corresponding fourth-order cumulants. Applying this method, the quality of the results is far superior to the traditional methods.

Algorithms↗

PubMed1992

Pharmacodynamics of venlafaxine evaluated by EEG brain mapping, psychometry and psychophysiology.

1. In a double-blind, placebo-controlled study the effects of venlafaxine--a novel nontricyclic compound inhibiting neuronal uptake of serotonin, noradrenaline and to a lesser extent dopamine--were investigated utilizing EEG brain mapping, psychometric and psychophysiological measures. 2. Sixteen healthy volunteers (eight males, eight females) aged 21-36 years received randomized and at weekly intervals single oral doses of placebo, 12.5 mg, 25 mg and 50 mg venlafaxine. EEG recordings, psychometric and psychophysiological tests, and evaluation of pulse, blood pressure and side-effects were carried out at 0, 2, 4, 6, and 8 h. 3. EEG brain mapping demonstrated that venlafaxine exerted a significant action on human brain function as compared with placebo at all three doses, characterized mostly by attenuation of absolute power, increase of relative delta/theta and beta, and decrease of alpha power, as well as by an acceleration of the total centroid fronto-temporally and by its slowing centrally and parietally. These findings are similar to antidepressants such as imipramine. Topographically, drug-induced alterations were most pronounced over both fronto-temporal and the right temporal to temporo-occipital regions. 4. Psychometric and psychophysiological investigations demonstrated significant dose-dependent psychotropic properties of the drug. Multivariate statistics exhibited an improvement of both the noopsyche (e.g. attention, concentration, attention variability, memory, fine motor activity, reaction time performance) and thymopsyche (e.g. drive, wakefulness)) but also significant psychophysiological activation (e.g. in c.f.f., pupillary and skin conductance measures). 5. Time-efficiency calculations showed significant central effects from the 2nd hour onwards, with increasing differences between placebo and treatment up to the 8th hour. Nausea was the most frequent complaint and appeared dose dependent.

Adult↗

PubMed1991

Evolution of technetium-99m-HMPAO SPECT and brain mapping in a patient presenting with echolalia and palilalia.

A 78-yr-old woman presented with transient echolalia and palilalia. She had suffered from Parkinson's disease for 2 yr. Routine laboratory examination showed hypotonic hyponatremia, but was otherwise unremarkable. Brain mapping revealed a bifrontal delta focus, more pronounced on the right. Single photon emission computed tomography (SPECT) of the brain with technetium-99m labeled d,l hexamethylpropylene-amine oxime (99mTc-HMPAO), performed during the acute episode showed relative frontoparietal hypoactivity. Brain mapping performed after disappearance of the echolalia and palilalia, which persisted only for 1 day, was normal. By contrast, SPECT findings persisted for more than 3 wk. Features of particular interest in the presented patient are the extensive defects seen on brain SPECT despite the absence of morphologic lesions, the congruent electrophysiologic changes and their temporal relationship with the clinical evolution.

Aged↗

PubMed1999

Stroke recovery. Lessons from functional MR imaging and other methods of human brain mapping.

The mechanisms underlying patient recovery after stroke remain incompletely understood. Human brain mapping methods such as functional MR imaging provide insights into stroke recovery mechanisms. After a unilateral brain insult, lasting changes take place in both hemispheres and along the rim of a cortical infarct. Such information may be of value in the design of therapies targeting stroke recovery.

Brain Mapping↗

PubMed1988

Topographic brain mapping of EEG before and after open-heart surgery.

The brain function of 60 patients undergoing open-heart surgery (36 patients receiving coronary artery bypass, 21 patients valve replacements, 3 both) was investigated before and 10 days after the operation utilizing topographic brain mapping of the electroencephalogram (EEG). The postoperative EEG changes were characterized by a slight delta-theta increase, an alpha decrease [especially in the fast alpha (10.5-13 Hz) band] and a beta increase in the relative power. The total power and the absolute power of the delta-theta, alpha and beta showed a decrease, the dominant frequency a significant slowing from 9.7 to 9.3 Hz. The centroid of alpha and beta activity decreased as well. These results are similar to findings obtained in patients with organic brain syndrome. The EEG changes were prominent over the left hemisphere, which may be of particular clinical relevance.

Adult↗

PubMed1992

[Brain mapping for discriminating age related changes from dementia].

BM-EEG (Brain Mapping) and BM-P300 was studied for age related changes in 63 healthy controls (17.1-87.9 years). Additionally the discriminative power of both functional measures was tested in 21 patients with the clinical diagnosis (NINCDS-ADRDA) of probable dementia of Alzheimer type (DAT) of mild to moderate degree (Global Deterioration Scale, 4.2 +/- 2.6). For global and regional absolute and relative power values in the 4 frequency bands alpha, beta, theta and delta, the alpha-peak, P300 latency and amplitudes, quantitative and topographical aspects were analysed. Despite a broad variation of normal values both tests revealed age related changes. For separation between DAT and normal controls BM-EEG was superior to BM-P300. Relative global and regional theta power was the most sensitive parameter to discriminate both groups. BM data are compared with reported findings of traditional EEG and cognitive evoked potentials.

Adolescent↗

PubMed1991

[Demonstration of the central effects of D,L-kawain with EEG brain mapping].

In a double-blind, placebo-controlled EEG-brain-mapping study Saletu et al. demonstrated the encephalotropic effects of single doses of 200, 400 and 600 mg D,L-kawain in healthy volunteers. The substance induced a dose-dependent increase in delta, theta and alpha 1 power, as well as a decrease in alpha 2 and beta power. The shift towards low frequences indicated a sedative effect of higher doses of D,L-kawain. Changes were most pronounced in the frontal regions. The pharmacodynamic peak was reached in the 1st hour; a 2nd peak was seen in the 8th hour. D,L-kawain at a dose of 200 mg had an initial activating effect, followed at a later stage by a mild sedative effect. Self-rating scales suggested activation after 200 mg, but mild sedation after 600 mg. Psychometric performance improved after all D,L-kawain doses; there were no adverse reactions.

Anti-Anxiety Agents↗

PubMedDate not supplied

EEG brain mapping and psychometry in age-associated memory impairment after acute and 2-week infusions with the hemoderivative Actovegin: double-blind, placebo-controlled trials.

In a double-blind, placebo-controlled study the encephalotropic and psychotropic effects of Actovegin--a protein-free metabolically active hemoderivative improving oxygen and glucose utilization--were investigated in age-associated memory impairment (AAMI) patients, utilizing EEG brain mapping, psychometric and psychophysiological analyses. Each patient had a treatment of 2 weeks with 250 ml 20% Actovegin and 250 ml placebo daily with an interval of 3 weeks in between (the order of drugs sequence was randomized). Pharmacodynamic evaluations were carried out 0, 2, 4, 6 and 8 h after the administration of one single infusion on day 1 (acute effect), at 0 h on day 15 (subacute effect) as well as 2, 4, 6 and 8 h after one additional superimposed infusion on day 15 (superimposed effect). EEG brain mapping demonstrated that Actovegin exerted a significant action on the human brain function as compared with placebo characterized by a decrease of delta and theta, an increase of alpha-adjacent slow beta, a decrease of fast beta, an acceleration of the centroid of the delta/theta and alpha activity, a slowing of the beta centroid and an increase of the centroid of the total activity. Topographically the encephalotropic effects were mostly pronounced in the parietal, frontocentral and temporooccipital regions. These changes are indicative of an improvement of vigilance which was proven also by psychometric investigations at the behavioral level. Actovegin improved the noopsyche mostly in regard to attention, memory and rigidity/perseveration measures. In regard to the thymopsyche an improvement was noted in mood, affectivity, well-being and sedation. Psychophysiological evaluations demonstrated an increase in CFF, skin conductance, pupillary diameter and shortening of the latency and augmentation of the amplitude of the pupillary response. Time-efficacy calculations exhibited more effect after subacute than acute administration with the pharmacodynamic maximum in the 4th h after the superimposed dose. Evaluations of pulse, blood pressure and side effects demonstrated a very good tolerability of the drug. Our present neurophysiological, psychometric and psychophysiological findings confirm earlier results obtained in elderlies with similar methodology.

Aged↗

PubMed1997

Characterization of dynamic 3-D PET imaging for functional brain mapping.

Methods for optimizing the acquisition, reconstruction and analysis of positron emission tomography (PET) images for functional brain mapping have been investigated. The scatter fraction and noise-equivalent count rate characteristics were measured for the ECAT 951/31R PET scanner operating in septa-extended two-dimensional (2-D) and septa-retracted three-dimensional (3-D) modes. The 3-D mode is shown to provide higher signal-to-noise images than the 2-D mode at specific activities less than 30 kBq/ml. To enable increased temporal resolution in dynamic 3-D PET activation studies, a parallel version of the 3-D reconstruction algorithm was developed. Implementation of the reprojection algorithm on an 88 processor 1860 supercomputer resulted in a more than tenfold increase in reconstruction speed compared to a single 1860 processor system. An investigation of the optimal duration for imaging brain activations was undertaken in 12 normal subjects using repeated H2(15)O slow infusions and a visually presented lexical decision task. The significance of change in regional cerebral blood flow (CBF) was determined using statistical parametric maps for images acquired during stimulation, immediately after stimulation, and commencing 1 min after cessation of the stimulus. Regions of CBF change were detected in all three images. Dynamic 3-D, or four-dimensional (4-D), PET activation scanning is shown to be practical and likely to further improve the sensitivity of PET for detection of subtle regional CBF changes in functional brain mapping research.

Adult↗

PubMed1989

Discrimination of mode of action of anxiolytics using an integrated computer data bank and Dynamic Brain Mapping (CNS effects of diazepam and lorazepam).

In a double-blind, placebo-controlled, crossover study, the CNS effects of intravenously administered diazepam and lorazepam were investigated in anxious subjects through the quantitative pharmaco-EEG (QPEEG) method. For up to 4 1/2 hours following administration the effects of each substance on brain function were measured using computer analyzed EEG recordings (CEEG) and a new technique called Dynamic Brain Mapping. The following observations were made: 1. Both active drugs produce statistically significant CNS effects as measured by CEEG changes. These changes were observed earlier with diazepam than with lorazepam. 2. Although both compounds are classified as anxiolytic by the routine computer EEG data base, the detailed brain mapping technology indicated that the CNS effects of diazepam and lorazepam were quantitatively and qualitatively different. 3. Clinical CNS side-effects (sedation) were seen more frequently with lorazepam than with diazepam. This was consistent with the EEG slowing producing properties of lorazepam. The EEG fast activity which is characteristic for all anxiolytics was established more with diazepam than lorazepam.

Adult↗