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Assessment of mental effort by means of slow brain potentials.
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Event-related potentials in migraine: realizations and prospects.
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Visual dominance: an information-processing account of its origins and significance.
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EEG correlates of cerebral dominance.
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[Two components in bereitschaftspotential].
In this work the BP onsettimes of voluntary movement and instructed movement were compared. Our results show that there is no significant difference (P > 0.05) between BP onsettimes of the two kinds of movement and that BP occurs before the instruction of movement. The early component of BP, i.e. the negative wave before the presentation of instruction, had no relationship with movement preparation. For the analysis of the source of the BP early component, the BP onsettimes of unconscious eyeblink and instructed eyeblink or self-initiated voluntary eyeblink were compared. It was found that the BP onsettime of unconscious eyeblink was much shorter than that of the two kinds of conscious (P < 0.05) eyeblink. These results suggest that the BP early component is elicited by psychological factors, rather than the result of the preparatory processes of movements in the brain.
[Diagnostic and therapeutic management of the patient with headache].
The different diagnostical and therapeutical approaches of cephalalgia are described. The importance of a pluridisciplinary management is stressed.
Predictive validity of a Spanish-language adapted version of the Anton Brenner Developmental Gestalt Test of School Readiness.
For an adapted version of the Anton Brenner Developmental Gestalt Test of School Readiness, developed for experimental use in Costa Rica, the present objective was to ascertain its predictive validity. With 312 preschool children during the first semester and at the end of kindergarten, the relationship between test scores and failing or passing first grade was examined and found similar. The average hit rate (percentage of children with and without school problems who were classified correctly) was 84%, the test's sensitivity (percentage of children with difficulties identified correctly) was 23%, and its specificity (percentage of children correctly identified who did not have school problems in first grade) was 97%. The test showed almost a 7:1 ratio for misclassifying false positives and false negatives. It seems advantageous to use the test in the first semester to have time to remedy difficulties during kindergarten.
EEG-blocking before and during voluntary movements: differences between the eyes-closed and the eyes-open condition.
Movement-related EEG periods of 1 s duration were analyzed by fast Fourier transformation in the Bereitschaftspotential (BP) paradigm in 21 healthy, right-handed normals. Spectra of the rest period and the BP period before the onset of the voluntary movement, and of the rest period and the movement period, were compared in order to describe blocking effects before and during movement execution (fast fist closure of the right hand). When comparing the rest period and the movement period with the eyes closed as well as with the eyes open, blocking was pronounced in both conditions within the total frequency range of the alpha-band, especially at positions contralateral to the movement over the motor cortex (C3') and the parietal cortex (P3) as well as at the parietal midline electrode (Pz). Moreover, when comparing the spectra of the rest and the BP periods in the eyes-closed condition, significant differences were again seen, with lower values during the BP period at C3' and P3. We were, however, able to observe over the parietal cortex an increase of alpha power in the 10 Hz range during the BP period with the eyes opened and fixated. This increase during the BP period in the eyes-open condition was not found when the eyes were closed. This paradoxical phenomenon of an increase of power with the eyes opened instead of blocking during the BP period, as observed in the eyes closed, may be due to an additional activation effect on the already activated (blocked) EEG in the eyes-open condition during fixation.
[The use of the contingent negative wave in neurology and psychiatry].
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Barbiturate effects on brain functioning (CNV) and attention performance in normal men [proceedings].
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Eyeglass MEDRETE: practical considerations (a user's guide).
This article presents the experiences of two independent practitioners who participated in eyeglass-dispensing medical readiness training exercises (MEDRETEs) in Central America. It explains the importance of defining personnel policies, having the proper equipment, utilizing the retinoscopists optimally, and having an adequate supply of eyeglasses with plus lens power for indigenous persons in this geographic area. To maximize the effectiveness of a MEDRETE, a dispensing optician and two teams of translators are needed. Triage of patients will permit the optimal number of refractions and distribution of corrective lenses to those most in need. Fitting indigenous patients with corrective lenses in one of the more tangible and lasting effects of a MEDRETE. It contributes not only to patient satisfaction but possibly to improved relationships with the host nation.
S2 probability and CNV [proceedings].
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[Clinico-neurophysiological correlations in migraine].
The more accurate definition of the role of cerebral mechanism in migraine development by means of contingent negative deviation (CND) method was the aim of this investigation. The significant alterations of some parameters were revealed in patients with migraine between the fits as compared with controls. The same indices were normal during the very fits. The CND indices were similar in patients with chronic Headache of strain and healthy individuals. The clinical neurophysiological analysis didn't reveal any significant dependence of CND changes clinical peculiarities and anxious and depressive disorders. The significant elevation of CND parameters observed between the attacks suggests presence of superfluous activity in cerebral structures (noradrenergic mainly) in patients with migraine without aura. Such alterations in their action lead, apparently, to headache attack development.
[Event-related brain potentials].
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The use of event-related slow potentials of the brain as an objective method to analyse the actions of centrally-active drugs in man [proceedings].
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[The adaptive capacities of patients with panic disorders (a psychophysiological study)].
Contingent-negative deviation (CND) and orientational reaction (OR) were studied in 9 women suffering from typical (according to DSM-III-R) panic disorders (PD) and 12 healthy females. CND recording was made after giving neutral (70 dB, 1000 Hz) and stress (120 dB, 2000 Hz) pairs of sounds. Patients with PD were divided in two groups depending upon CND amplitudes. The first group (4 patients) was distinguished from healthy individuals by high CND amplitude (which significantly decreased after reaction on stress sound), by delay of extinction of cutaneogalvanic reaction (CGR) and by higher electromyogram amplitude. The second group (5 patients with more severe course of PD) was characterized by low amplitudes of CND and electromyogram, by absence of changes in CND after stress sound, by delay of extinction of CGR and nonspecific response. Above-mentioned data were evidence of psychophysiological heterogeneity of typical PD. The results were interpreted from a position of adaptive abilities of patients with PD, using ineffective and immature psychophysiological strategies of overcoming stress.