Clinical EEG (electroencephalography)最新文献

The goal of this study was to determine distinctive aspects of Mozart music that may explain the "Mozart Effect," specifically, the decrease in seizure activity. As many as 81 musical selections of Mozart, but also 67 of J.C. Bach, 67 of J.S. Bach, 39 of Chopin and 148 from 55 other composers were computer analyzed to quantify the music in search of any distinctive aspect and later to determine the degree to which a dominant periodicity could be found. Long-term periodicity (especially 10-60 sec, mean and median of 30 sec), was found often in Mozart music but also that of the two Bachs, significantly more often than the other composers and was especially absent in the control music that had no effect on epileptic activity in previous studies. Short-term periodicities were not significantly different between Mozart and the Bachs vs. the other composers. The conclusion is that one distinctive aspect of Mozart music is long-term periodicity that may well resonate within the cerebral cortex and also may be related to coding within the brain.

We examined 385 children whose EEG showed high voltage potentials evoked by taps applied to one or both feet or hands (SES). The relationship between characteristics of SES and the occurrence of epileptic seizures and the characterization of epileptic syndromes were studied. Ninety-one children (23.6%) had epilepsy, 42 (10.9%) had only febrile convulsions and 252 children had other complaints. Epilepsy occurred in a higher proportion of cases when: SES by foot tapping were multiphasic, with high amplitude or SES were obtained by hand stimulation and there was spontaneous epileptiform activity in the EEG. The following epileptic syndromes were diagnosed: benign childhood epilepsy with centrotemporal spikes in 21 cases, benign epilepsy of childhood with occipital paroxysms in 2, benign psychomotor epilepsy in 1, "partial idiopathic others" in 43, generalized idiopathic in 8, symptomatic epilepsies in 13 and undetermined in 3 cases. In most cases SES were observed in children without evidence of cerebral organic lesion, suggesting the existence of an age-related, functional mechanism. Some characteristics of SES and the occurrence of spontaneous epileptiform activity showed a positive association with epileptic seizures. SES occurred in different types of partial and generalized epilepsies of childhood but in nearly 50% of the cases with epilepsy, there was a benign condition involving mainly the parietal lobe with versive, unilateral and sleep-generalized seizures.

Migraine affects 10% of the population, yet there is no proven diagnostic test. To date the most promising neurophysiological diagnostic technique has been the analysis of cerebral responses to photic stimulation or flicker (the "H" response). This test has proved to be sensitive in patients with "classic" migraine, but has not been re-evaluated since the introduction of the 1988 International Headache Society (IHS) classification system. In 33 migraineurs, we found that the "H" response was sensitive (86.4%) and specific (97.5%) in those with migraine defined according to IHS Committee as type 1.2.1 (typical aura) and type 1.1 (without aura), but not in basilar migraine (1.2.4).

The human immunodeficiency virus causes serious, progressive and irreversible deterioration of the immunocompetence system and of the nervous system, so neurological pathology in infected patients is frequent (30-40%), affecting both the central and the peripheral nervous systems. There are different clinical and laboratory indicators of bad prognosis, considering the important neurotropism of the virus. This study attempts to evaluate which neurophysiological parameters are altered during the initial phases of infection by HIV. A total of 46 individuals were studied, 30 seronegative and 16 seropositive in stage A of the CDC-93 classification. Motor and sensory conduction studies were carried out on all of them on the upper and lower extremities, as well as visual, somatosensory and auditory evoked potentials and endogenous potentials, mainly P300. The analysis of the neurophysiological parameters evaluated in our series, showed alterations of the conduction velocity of the sural nerve, latency of N1 of the SSEP of median and posterior tibial nerves and P300 in the initial phases of the infection even in the absence of clinical symptomatology.

To study age-dependent changes in coupling between cortical neural networks we applied a new method (omega complexity) to determine overall coherence of EEGs of 34 subjects ranging in age from 3 months to 16 years. We found that the functional coupling between different brain regions is low at birth and increases significantly in the first two decades of life. We suggest that this coupling depends critically upon the system of associational and callosal fibers which is unmyelinated at birth, and which only finishes myelinization in the second or third decade. Thus age-dependant changes in omega complexity may reflect maturation of brain structures underlying higher cerebral functions. If these results can be replicated, preferably in prospective, cohort rather than transectional type studies, omega complexity might prove to be clinically useful as an objective, quantitative measure of brain maturation.

The present study of coherence analysis, in 16 healthy male volunteers, aged 24-31 years, showed that the administration of 0.25 mg of scopolamine significantly reduced interhemispheric coherence in the delta and beta-1 bands in the resting state. Scopolamine also caused a significant increase both in EEG coherence during PS and in PS-related coherence reactivity in the beta band. In addition, this compound significantly reduced total WMS scores. These findings suggest that, in addition to causing cognitive impairments, central cholinergic dysfunction can alter interhemispheric functional connectivity under both nonstimulus and stimulus conditions.

This report attempts to replicate our recent finding of a significantly reduced sensory gating response in medically and psychiatrically normal chronic marihuana users. After exclusions, 10 normal heavy marihuana users (> or = 3 times per week) and 10 normal non-user controls were tested with the paired auditory P50 sensory gating procedure. Sensory gating ratios were significantly higher (i.e., impaired suppression) for THC users as compared to controls. Using combined data from the current and previous report, the degree of sensory gating impairment among THC users was significantly correlated with the frequency of marihuana use per week. Suggestions for further research are offered.

This study attempted to better define clinical and EEG features for differential diagnosis between epilepsy and migraine in children with occipital epileptiform EEG abnormalities. We studied 126 children (57 males, 69 females; age 4-18 years) suffering from epilepsy (63), migraine (43) or both (20). Patients were selected because of the presence of epileptiform abnormalities in the occipital regions on their EEG at rest. Differences among groups were statistically analyzed (Pearson chi square; ANOVA) for sex, age at onset of seizures and migrainous attacks, family history, ictal signs and symptoms, EEG at rest (unilateral vs bilateral distribution of epileptiform abnormalities), and EEG during Hyperventilation (HV) and Intermittent Photic Stimulation (IPS). Significant differences were found in family history, ictal signs and symptoms, EEG at rest and during activation tests. A family history of epilepsy, visual symptoms such as colored hallucinations and micro/macropsias, frequently associated with clinical signs in the visual system (eye deviation, nystagmus), unilateral EEG abnormalities, and abnormal response to IPS were closely related to diagnosis of epilepsy. On the other hand, a family history of migraine, visual symptoms such as amaurosis and scotomata, without evident clinical signs, bilateral EEG abnormalities, and no changes during IPS were significantly related to migraine. In conclusion, these clinical and EEG differences should be considered in the differential diagnosis between epilepsy and migraine in children with occipital epileptiform EEG abnormalities.

Alpha, theta and alpha-theta enhancements are effective treatments of the anxiety disorders (Table 1). Alpha suppression is also effective, but less so (Table 2). Perceived success in carrying out the task plays an important role in clinical improvement. Research is needed to find out how much more effective they are than placebo, and which variables are important for efficacy. Variables needing study are: duration of treatment, type and severity of anxiety, number and type of EEG waveforms used, pretreatment with other kinds of feedback, position and number of electrodes, and presence of concomitant medication.