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Biomedical subjects

D O Walter

Publications and source records attributed to D O Walter.

At least 37 records · Page 2Linked to original sources
PubMed1987

Alexithymia and the split brain. V. EEG alpha-band interhemispheric coherence analysis.

Electroencephalographic (EEG) recordings were obtained while 6 completely commissurotomized patients, 2 partially commissurotomized patients, and 8 precision-matched normal control subjects watched 4 times a film symbolically depicting death. Our hypothesis was that alexithymia--a diminished capability to verbally express moods, symbols, and feelings--would be greater for patients because loss of cerebral commissures reduces interhemispheric communication, separating right-hemisphere-dependent affective understanding and left-hemisphere-dependent verbalization. Path and covariance structure analyses confirmed that callosotomy decreased alpha-band EEG coherences (after adjustment for mean intrahemispheric coherence) between pairs of scalp electrode channels placed homologously over frontal, parietal, and temporal lobes of the brain. This result occurred both for an index of interhemispheric coherence and for a latent variable indicated by the 3 adjusted coherences. Reduced levels of interhemispheric coherence in turn increased alexithymia, for an overall index and for a latent variable indicated by lexical-level content-analytic measures of verbal responses to the filmic stimulus.

Adult↗
PubMed1986

Alexithymia: an experimental study of cerebral commissurotomy patients and normal control subjects.

This study assessed alexithymia in six patients with complete cerebral commissurotomy, two patients with partial commissurotomy, and eight matched control subjects. Comparisons were based on content-analytic measures of the subjects' spoken and written responses to a film that symbolically represented death and loss. The commissurotomized patients were more alexithymic on all four lexical-level variables, all six sentential-level variables, and all six global-level variables. Discriminant function analysis found a linear combination of four variables that effectively discriminated groups of fully commissurotomized, partially commissurotomized, and normal control subjects and correctly classified 15 of the 16 subjects.

Adult↗
PubMed1985

Alexithymia and the split brain. I. Lexical-level content analysis.

8 cerebral commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-minute videotaped film symbolically depicting the deaths of a baby and of a boy. After each of 4 showings, all subjects were questioned about the symbolic and emotional contents of the film. Content analyses of the subjects' spoken and written responses were carried out on the lexical level. The commissurotomized patients, in comparison to their normal controls, used a lower percentage of affect-laden words, had a higher percentage of incomplete sentences, used a higher percentage of auxiliary verbs, and used a lower percentage of adjectives. Commissurotomy patients were significantly closer to the alexithymic pole of a factor derived from these 4 variables.

Adult↗
PubMed1985

Alexithymia and the split brain. II. Sentential-level content analysis.

The Hoppe-Bogen finding of alexithymia in 12 commissurotomy patients is examined, using 6 sentential-level items corresponding to 6 of the 8 key alexithymia items in the Beth Israel 'Psychosomatic Questionnaire'. 8 of the same commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-min videotaped film about death. Content analyses of the subjects' spoken and written responses to this film were carried out, with directional support found for all items; however, only 2 of these differences in group means were statistically significant. The items were factor analyzed, and a 1-factor solution obtained. Factor score comparisons replicated the earlier study, as commissurotomy patients were found to be more alexithymic than normal controls.

Affective Symptoms↗
PubMed1985

Alexithymia and the split brain. III. Global-level content analysis of fantasy and symbolization.

8 commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-min videotaped film about death. Content analysis of the subjects' spoken and written responses to this film was carried out on the global, interpretive level, for 2 fantasy and 4 symbolization variables. Commissurotomy patients were found to be significantly more alexithymic than normal controls for 3 of the symbolization variables, for factor-analytic measures of fantasy and symbolization, and for an over-all measure of alexithymia derived from these 2 factors and lexical-level and sentential-level measures of alexithymia.

Affective Symptoms↗
PubMed1985

Alexithymia and the split brain. IV. Gottschalk-Gleser content analysis, an overview.

A structural explanation of psychosomatic personality structure is proposed, that of a functional or physical deconnection of the two cerebral hemispheres. If the affective and symbolic energies of the right hemisphere cannot be externalized through verbal expressions of the left hemisphere (alexithymia), then they are apt to be directed inward, thereby contributing to psychosomatic personality structure. In an experiment, 8 cerebral commissurotomy patients and 8 precision-matched normal control subjects were shown a 3-minute videotaped film symbolically depicting the deaths of a baby and a boy. Gottschalk-Gleser content analysis of the subjects' verbal responses to the film was carried out for anxiety and hostility scales. A complex of shame and total anxiety in combination with hostility directed both inward and outward, was interpreted as an indicator of 'psychosomatic personality structure'. Cerebral commissurotomy patients showed a significantly higher level of psychosomatic personality structure than did normal controls.

Affective Symptoms↗
PubMed1984

Biological processing.

The organization of brain processes leading to language and movement show important parallels with one another and also express important aspects of biological organization in general. Four major differences between biological processes and their commonly proposed analogues, machine processes, are as follows. 1) Reduction is not simplification in biological analysis; rather the subsystems that result from separation of parts of a biological system are themselves complex, often potentially viable, systems. 2) Machine processes are typically generalized, or, if specialized, they are specialized by connecting general-type subsystems in special ways. But biological systems are typically specialized at many levels, both in subsystems and their connections. 3) The history of a biological system is often an intimate and inseparable part of its structure. Furthermore biological systems never develop alone or de novo. Not only do they develop in clusters of contemporaries, they also develop in the presence of an older generation and a "culture." 4) Not only do formal logics have some constraints that biological minds may not have (e.g., internal consistency and universality), formal logics require descriptions of qualitative phenomena in a language that is inadequate and (as a deeper issue) may always require parsing a meaningful whole into approximate parts (e.g., as in writing this abstract). Instances of contrasts between biological systems and machine-type systems are seen in language and movement phenomena, such as embodying a distinction between purposes and causes and having flexibly reorganizable subassemblies, multiple goals, and motor equivalence.

Brain↗
PubMed1984

Computerized topo-EEG spectral maps: difficulties and perspectives.

An electric potential measurement tells us only about the difference between two electrode locations. When prior experiments or present measurements prove that an electrode's location is inactive (especially in 'mono-polar' or scalp-to-reference technique), then EEG records and EEG maps can be interpreted regionally near each electrode location. Topographical mapping requires spatial interpolation which is one factor involved in spatial resolution. The interpolation algorithm has been studied by changing the power exponent n of the interelectrode distance d. When n is close to zero, interpolated values are all equal to the average of the four electric potential measurement Vs bounding the quadrilateral in which the interpolated points of the EEG map are located. When n is very high (n = 20 or higher), the values are essentially equal to the V which is at the minimum distance d. For n = 1, the map seems unlikely to represent the true scalp field. The choice between n = 2 and n = 3 is difficult, but n = 3 EEG mapping looks better (more plausible) and is our regular choice. The choice of recording/reporting method has also been studied. If the quantitative EEG map is linearly calculated from observations, the interpretation of record activity resulting from charge separation near the non-reference electrode attached to a particular channel is only possible when inactivity can be assured. This is completely different when the quantity mapped is not linearly calculated from observations (like power values or rms amplitudes in microvolts).(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Mapping↗
PubMed1981

Periodicity of sleep states is altered in infants at risk for the sudden infant death syndrome.

The normal succession of sleep and waking states through a night is disturbed in infants at risk for the sudden infant death syndrome. Compared with normal infants, siblings of the sudden infant death syndrome victims have longer intervals between active sleep epochs at particular times during the night in the newborn period and a decreased tendency to enter short waking periods at 2 and 3 months of age. The latter finding is interpreted as an increased tendency to remain asleep, or a relative failure to arouse from sleep in infants at risk.

Age Factors↗
PubMed1981

Methods for finding single generators, with application to auditory driving of the human EEG by complex stimuli.

A method is presented for searching any number of simultaneous time series (e.g. from different EEG electrodes) for single generators within a frequency band. The method was applied to human EEGs taken during conditions of listening to complex rhythmic (Mozart symphony and chanting) and non-rhythmic (conversation) sounds. The method indicated a tendency towards single generation in the alpha (8-12 Hz) band during the rhythmic conditions. The method was then extended to test for synchrony between the EEG signals and the auditory signal (as a function of frequency). Such synchrony (auditory driving) was indicated during rhythmic conditions in the alpha band.

Acoustic Stimulation↗
PubMed1980

Choosing the right fictions of scientific law.

Fictions are well established in the theory and practice of civil law; similar importance is here claimed for fictions in the theory and application of scientific law. A puzzle from quantum mechanics, previously referred to in this Journal [Am. J. Physiol. 238 (Regulatory Integrative Comp. Physiol. 7(: R277-R290, 1980], is reinterpreted by suggesting quantum logic as a source of relevant fictions, which indicate a solution to that puzzle. Another physiological application of quantum theory suggests that the concept of "the state of the brain" may, in its usual classical sense, not be useful for an individual brain--but may well be suggestively modeled by a quantum state. The notion of "myths," usually only pejoratively applied in positivistic writings, is suggested for rehabilitation, in view of their helpful function (often unnoticed) even in positivistic thinking. Finally, an example of a biological simulation (of a tumor by a cell culture) is presented, to show that its multilayered fictionalizations illustrate the surprising fact that a simulation that is insulated from the system being simulated can be logically more powerful than any uninsulated simulation.

Biological Evolution↗
PubMed1980

Influence of click sound pressure direction on brain stem responses in children.

Brain stem auditory responses were evoked by stimulation with condensation (C) and rarefaction (R) clicks separately. The latencies of the first five waves of the response were compared in response to the two sound pressure directions. Responses to R clicks were significantly shorter than responses to C clicks for wave 4, in the absence of consistent response differences in the other waves.

Acoustic Stimulation↗
PubMed1979

The maturation of vestibular nystagmus in infancy and childhood.

The displacements, durations, and velocities of the slow and fast components of both the primary and secondary nystagmus induced by constant angular acceleration were measured in 46 normal children 1 month to 11 years old. There were significant changes in nystagmus parameters in respect to maturation. The young infant had larger amplitude, higher velocity beats than the older child during both the primary and the secondary nystagmus. Parameters describing both the primary and the secondary nystagmus reached their peak values and terminated earlier in the infant than in the older child. Although the slow component velocity during secondary nystagmus was much slower than during the primary nystagmus at all ages, the secondary nystagmus/primary nystagmus ratio was significantly greater in early infancy. Thus, in infancy, as compared with later childhood, the vigor of the secondary nystagmus was disproportionately greater than the primary nystagmus. These results were discussed in relation to the maturation both of vestibular responsiveness and of vestibular adaptation.

Age Factors↗
PubMed1978

Development of sinus arrhythmia during sleeping and waking states in normal infants.

The development of variability in heart rate (HR) due to respiration (sinus arrhythmia; SA) has been examined in normal infants from birth through the first 6 months of life. Two aspects of HR variation were examined: the absolute variation at the median respiratory frequency, or extent of sinus arrhythmia (XSA), and the degree to which HR follows respiration regardless of the absolute amount of variation, or coherence of sinus arrhythmia (CSA). Extent of sinus arrhythmia tended to be highest in quiet sleep (QS), lower in active or REM sleep (AS), and lowest in waking (AW), especially after 2 months of age. Extent declined at 1 month of age in QS, but rose over the first 6-month period in all states. During this same period, CSA was also highest in QS, lower in AS, and lowest in AW. Coherence in QS also declined at 1 month and rose between 1 and 6 months; however, no age effects were found in other states. Heart rate was negatively correlated with XSA, but less so with CSA. Sleep state appears to have a significant effect on cardiorespiratory coupling, and this coupling undergoes dramatic changes at 1 month in QS.

Arrhythmia, Sinus↗