Changes In Cerebral Electrical Activity Research Articles

Early predictors of short term neurodevelopmental outcome in asphyxiated cooled infants. A combined brain amplitude integrated electroencephalography and near infrared spectroscopy study

Background: Brain Cooling (BC) represents the elective treatment in asphyxiated newborns. Amplitude Integrated Electroencephalography (aEEG) and Near Infrared Spectroscopy (NIRS) monitoring may help to evaluate changes in cerebral electrical activity and cerebral hemodynamics during hypothermia. Objectives: To evaluate the prognostic value of aEEG time course and NIRS data in asphyxiated cooled infants. Methods: Twelve term neonates admitted to our NICU with moderate-severe Hypoxic-Ischemic Encephalopathy (HIE) underwent selective BC. aEEG and NIRS monitoring were started as soon as possible and maintained during the whole hypothermic treatment. Follow-up was scheduled at regular intervals; adverse outcome was defined as death, cerebral palsy (CP) or global quotient <88.7 at Griffiths’ Scale. Results: 2/12 Infants died, 2 developed CP, 1 was normal at 6months of age and then lost at follow-up and 7 showed a normal outcome at least at 1year of age. The aEEG background pattern at 24h of life was abnormal in 10 newborns; only 4 of them developed an adverse outcome, whereas the 2 infants with a normal aEEG developed normally. In infants with adverse outcome NIRS showed a higher Tissue Oxygenation Index (TOI) than those with normal outcome (80.0±10.5% vs 66.9±7.0%, p=0.057; 79.7±9.4% vs 67.1±7.9%, p=0.034; 80.2±8.8% vs 71.6±5.9%, p=0.069 at 6, 12 and 24h of life, respectively). Conclusions: The aEEG background pattern at 24h of life loses its positive predictive value after BC implementation; TOI could be useful to predict early on infants that may benefit from other innovative therapies.

Prognostic Value of Amplitude Integrated Electroencephalography (AEEG) and Near Infrared Spectroscopy (NIRS) in Cooled Infants with Hypoxic-Ischemic Encephalopathy (HIE)

Background and aims: Brain cooling (BC) represents the elective treatment in asphyctic newborns. aEEG and NIRS monitoring may help to evaluate changes in cerebral electrical activity and cerebral hemodynamics during hypothermia. Aims: To evaluate the prognostic value of aEEG time course and NIRS data in asphyctic cooled infants. Methods: 12 term neonates admitted to our NICU with a moderate-severe HIE underwent selective BC. aEEG and NIRS monitoring were started as soon as possible and maintained during the whole hypothermic treatment. Follow-up was scheduled at regular intervals; adverse outcome was defined as death, cerebral palsy (CP) or global quotient < 88.7 at Griffiths' Scale. Results: 2/12 infants died, 2 developed CP, 1 was normal at 6 months of age and then lost at follow-up and 7 showed a normal outcome at least at 1 year of age. The aEEG background pattern at 24 hours of life was abnormal in 10 newborns; only 4 of them developed an adverse outcome, whereas the 2 infants with a normal aEEG developed normally. In infants with adverse outcome NIRS showed a higher Tissue Oxygenation Index (TOI) compared with those with normal outcome (80.0±10.5% vs 66.9±7.0%, p=0.057; 79.7±9.4% vs 67.1±7.9%, p=0.034; 80.2±8.8% vs 71.6±5.9%, p=0.069 at 6, 12 and 24 hours of life, respectively). Conclusions: The aEEG background pattern at 24 hours of life loses its positive predictive value after BC implementation; TOI could be useful to early predict non responder infants that may benefit from other innovative therapies.

Hyperventilation Test-Related Changes of EEG in Children: Peculiarities Detected Using Periodometric Analysis

Computer periodometric analysis of EEG recorded from 169 healthy schoolchildren allowed us to calculate the quantitative indices characterizing the direction and intensity of dynamic changes in cerebral electrical activity induced by a hyperventilation test. Three main types of EEG reactions to hyperventilation observed in children of different age groups have been classified. The dependence of the frequency of types of EEG reactions of healthy children to the hyperventilation test on the age of the tested subjects and EEG type in the resting state was demonstrated.

Quantified EEG analysis monitoring in a novel model of general anaesthesia in rats

The aim of this research was to evaluate the safety and reliability of an anaesthetic mixture (Equitensine: pentobarbital, chloral hydrate, dihydroxypropane, ethanol) which, unlike other ‘classic’ anaesthetics, such as ketamine [ The Electroencephalogram in Anaesthesia, Springer, Berlin, 1984], has been demonstrated not to induce alterations in the extracellular concentrations of cerebral excitatory amino acids. Quantified EEG analysis monitoring and behavioural observation were used to quantify the degree and the time course of the changes in cerebral electrical activity, analgesia and sedation induced, in rats, by the compound under investigation. Equitensine (0.33 ml/100 g), administered intraperitoneally, induced analgesia (monitored by the tail flick method) for 60–70 min and a pattern of behavioural sedation (loss of the righting reflex) lasting, on average, 130–150 min. The EEG monitoring revealed a pattern typical of burst suppression which lasted 15–20 min, followed by another, lasting 270–300 min, characterized by slow waves of high amplitude. The quantified EEG analysis demonstrated that the changes in cerebral electrical activity lasted longer than behavioural observation suggested. The compound under examination was found to be safe, reliable and non-invasive to administer and sustain in all the animals, and quantified EEG analysis proved to be a very sensitive method for highlighting the functional changes in the central nervous system.

The psychophysiological investigation of multiple personality disorder: review and update.

In 1984 Putnam reviewed the literature on the psychophysiological investigation of multiple personality disorder (MPD). Since his review, a large number of studies have been conducted and reported in the literature and at professional conferences. Currently, psychophysiologic differences reported in the literature include changes in cerebral electrical activity, cerebral blood flow, galvanic skin response, skin temperature, event-related potentials, neuroendocrine profiles, thyroid function, response to medication, perception, visual functioning, visual evoked potentials, and in voice, posture, and motor behavior. We review the new research on the psychophysiological investigation of MPD from published, unpublished, and ongoing studies, and we attempt to place current findings into a conceptual framework. We have noted findings from unpublished and ongoing studies, and, perhaps unfortunately, they represent a large amount of the data presently available. We conclude with a critical analysis of current research methodology and suggestions for future research.

Acute toxicity of a nuclear magnetic resonance cerebral blood flow indicator in cats.

We studied trifluoromethane as a potential gaseous indicator in nuclear magnetic resonance measurements of cerebral blood flow. We considered the effects of trifluoromethane on cerebral blood flow in 17 cats and on the electroencephalogram and electrocardiogram in nine cats and compared these with the effects of the more toxic compound chlorodifluoromethane in five cats. Inhaled at 60%, trifluoromethane had no effect on cerebral blood flow, the cerebral metabolic rate for oxygen, or oxyhemoglobin content. At 70%, trifluoromethane sensitized the cats' hearts to epinephrine, but to a much lesser degree than 40% chlorodifluoromethane, and produced only moderate changes in cerebral electrical activity as measured by the electroencephalogram. We found trifluoromethane to be suitable for use in animals, but its toxicity needs to be studied further before it can be used in humans for the measurement of cerebral blood flow.

Dynamics of brain electrical activity.

In addition to providing important theoretical insights into chaotic deterministic systems, dynamical systems theory has provided techniques for analyzing experimental data. These methods have been applied to a variety of physical and chemical systems. More recently, biological applications have become important. In this paper, we report applications of one of these techniques, estimation of a signal's correlation dimension, to the characterization of human electroencephalographic (EEG) signals and event-related brain potentials (ERPs). These calculations demonstrate that the magnitude of the technical difficulties encountered when attempting to estimate dimensions from noisy biological signals are substantial. However, these results also suggest that this procedure can provide a partial characterization of changes in cerebral electrical activity associated with changes in cognitive behavior that complements classical analytic procedures.

Significance of Changes in Cerebral Electrical Activity at Onset of Cardiopulmonary Bypass

A study of 100 patients requiring open-heart surgery has been undertaken to ascertain whether prophylactic measures designed to minimise cerebral damage have influenced the incidence or severity of changes in cerebral electrical activity recorded at the onset of cardiopulmonary bypass. The incidence of change in cerebral electrical activity remains high but the severity of the disturbances has diminished as compared with a series investigated before prophylactic measures were introduced. Changes suggestive of cerebral depression were particularly notable in children under 10 years of age. The significance of these findings is discussed in the context of factors which might influence cerebral electrical activity at the onset of bypass.

Significance of changes in cerebral electrical activity at onset of cardiopulmonary bypass.

A study of 100 patients requiring open-heart surgery has been undertaken to ascertain whether prophylactic measures designed to minimise cerebral damage have influenced the incidence or severity of changes in cerebral electrical activity recorded at the onset of cardiopulmonary bypass. The incidence of change in cerebral electrical activity remains high but the severity of the disturbances has diminished as compared with a series investigated before prophylactic measures were introduced. Changes suggestive of cerebral depression were particularly notable in children under 10 years of age. The significance of these findings is discussed in the context of factors which might influence cerebral electrical activity at the onset of bypass.

The effect of extracellular potassium concentration on protein synthesis in guinea-pig hippocampal slices.

Abstract— We have measured the effect of small variations in extracellular potassium concentrations ([K+]) upon the incorporation of radioactively labelled amino acid into the protein of the isolated guinea‐pig hippocampal slice. The slice is super‐perfused with glucose fortified buffer and maintains an ATP concentration of 33–36 nmol/mg protein and incorporates lysine into protein at a rate of 0.82 pmol/(ig protein/h. Within the range of extracellular K+ from 1.3 to 8.1 mil the change in the rate of lysine incorporation into protein is proportional to the logarithm of the extracellular K+ concentration. Incorporation increases by about 100% over this range. Measurements of the specific activity of the presumed intracellular amino acid pool indicate that the effect of changes in extracellular [K+] is to alter the rate of protein synthesis rather than alter the availability of radioactively labelled precursor. Altering extracellular [K+] does not affect tissue levels of ATP or creatine phosphate, indicating that the effect on amino acid incorporation does not result from an effect upon energy metabolism. It is suggested that this effect of extracellular [K.+] may be a means by which changes in cerebral electrical activity lead to changes in the rate of protein synthesis in brain.

Comparison of the electrical response of the reticular formation, thalamus, and cortex to a series of identical stimuli from an induction coil

Single cutaneous electrical stimuli evoke the following changes in cerebral electrical activity: synchronization in the reticular formation, medial thalamus, and temporal cortex, with desynchronization in the sensory motor cortex. Low voltage stimuli produce changes in the EEG of the reticular formation which appear earlier than do those of the sensory motor cortex. In the author's opinion, pain is first signaled at the level of the brainstem, and later the excitation moves up to the higher levels.