Causal reasoning and the diagnostic process

Background: Causal reasoning as a way to make a diagnosis seems convincing. Modern medicine depends on the search for causes of disease and it seems fair to assert that such knowledge is employed in diagnosis. Causal reasoning as it has been presented neglects to some extent the conception of multifactorial disease causes. Goal: The purpose of this paper is to analyze aspects of causation relevant for discussing causal reasoning in a diagnostic context. Procedures: The analysis will discuss different conceptions of causal reasoning in medical diagnosis, discriminating primarily between narrow causal diagnosis and more thorough causal explanation. The theory of causes as non-redundant factors in effective causal complexes is used as an analytical background. Causal explanations are performed according to different causal models. Such models of diagnosis are assumptions concerning structure and mechanisms, which cannot be directly or immediately observed. Conceptions and results of causal search strategies differ, according to the focus of the searcher. Causal reasoning is also seen in diagnosis in a more extensive meaning: the pin-pointing of factors responsible for the condition of the patient at any time during the course of disease. Conclusion: Causal reasoning and diagnosis go well in hand, especially if both concepts are widened. The theory of causes as non-redundant components in effective causal complexes, modulated by what is referred to as the stop problem and causal fields, is valuable for explaining the many aspects of causal reasoning in medical diagnosis.     

Hypothetico-nomological aspects of medical diagnosis Part I: General structure of the diagnostic process and its hypothesis-directed stage

In medical diagnostic examination three main stages may be distinguished: (a) initial exploration, (b) hypothesis-directed investigation, and (c) final diagnosis making. The purpose of this work is to study some methodological problems concerning the second of the above stages of the diagnosis and to prepare a background for a mathematical model [30] of this process. In diagnostic problem solving, the reasoning proceeds along the main lines traced by some initial suggestions and passes through various intermediate elements which are connected with one another forming ramifying chains and nets of inferences and hypotheses. Such a complex mental construction is based on laws which form medical knowledge and reflect various regularities and relations, causal, structural, functional, and others. The main components of diagnostic reasoning may be divided into several classes according to their function and content: leading hypotheses, working hypotheses, main diagnostic hypotheses, statements accepted as certain, intermediary and reserve hypotheses, therapeutic suggestions of immediate consequence. In an example of diagnostic problem solving these types of propositions are defined and analysed. In diagnostic reasoning, as in every other process of rational problem solving, explanation of the observed symptoms and signs and testing of the explaining hypotheses play a predominant role. These procedures form successive, frequently numerous and diversified steps and stages of the reasoning, leading to the construction of a mental model of the patient's state. Some problems relative to the scheme of explanation, especially to that which is based on causal laws, are discussed.     

The brain and sodium homeostasis

Sodium homeostasis continues to be one of the principal areas of intense investigation in humoral physiology. This is not only because of its central role in major medical problems such as hypertension and edema. It also follows from the many intriguing problems of adaptations involving sodium control by animal species in the course of phylogenetic emergence from the oceans and irradiation into diverse ecological niches of terrestrial existence. Many of the central problems of this wide field of inquiry remain unsolved.     

The patenting process,innovation, and size

This paper focuses on the U.S. patenting process and how large and small entity inventors respond to it. In particular, a framework of patenting process events and activities related to success is developed and evaluated empirically, with a factor analysis revealing similarities and differences in the priorities of the two groups. The results have implications for both the conduct of the new product process under the law and for review and examination of public policy regarding patents. He received his Ph.D. from Lehigh University. His research interests include intellectual capital, intellectual property, and competitive intelligence. He has published in Journal of Marketing Management, European Journal of Marketing, Journal of Marketing & Public Policy, and Industrial Marketing Management.     

The reality principle, tragic knots, and the analytic process

Civilization and Its Discontents is shown to occupy a special place in Freud's development of psychoanalytic theory and technique. Especially emphasized is its implications for an inclusive understanding of the reality principle. The concept tragic knots is then defined and used to emphasize Freud's readiness to include tragic elements in that principle. An extended section then illustrates the spread of tragic knots into several diverse aspects of human existence: victimization, intimacy, and maintaining privacy. Finally, implications are drawn for the clinical assessment of working through unconscious conflicts.     

Vasopressin,glucose homeostasis,and sucrose taste preferences

Previous research indicates that vasopressin-containing (LE) rats are capable of adapting to the stress of food restriction, whereas vasopressin-deficient (DI) rats cannot adapt to this stressor. It has been postulated that abnormalities in glucose metabolism may be one of the factors leading to the demise of food-restricted DI rats. The present study was conducted to determine if taste preferences are altered in DI animals and if the presentation of exogenous glucose, in the form of sucrose solutions, can ameliorate the effects of the stress of food restriction. Four different concentrations of sucrose solutions were presented to LE and DI rats under the food-restricted condition. In both strains, an 8% sucrose solution was preferred over 0%, 16%, and 32% concentrations, with DI rats consuming more of this concentration than LE rats. Thus, when DI rats had the opportunity of maintaining glucose homeostasis by exogenous supplements, they maintained body weight, displayed no stomach pathology, and survived.     

Vasopressin, glucose homeostasis, and sucrose taste preferences

Previous research indicates that vasopressin-containing (LE) rats are capable of adapting to the stress of food restriction, whereas vasopressin-deficient (DI) rats cannot adapt to this stressor. It has been postulated that abnormalities in glucose metabolism may be one of the factors leading to the demise of food-restricted DI rats. The present study was conducted to determine if taste preferences are altered in DI animals and if the presentation of exogenous glucose, in the form of sucrose solutions, can ameliorate the effects of the stress of food restriction. Four different concentrations of sucrose solutions were presented to LE and DI rats under the food-restricted condition. In both strains, an 8% sucrose solution was preferred over 0%, 16%, and 32% concentrations, with DI rats consuming more of this concentration than LE rats. Thus, when DI rats had the opportunity of maintaining glucose homeostasis by exogenous supplements, they maintained body weight, displayed no stomach pathology, and survived.     

Irrelevant behaviour,information processing and arousal homeostasis

Summary This paper expands a new hypothesis on the causal mechanisms underlying irrelevant behaviour. It begins with a critical summary of earlier theories which attempted to explain displacement activities, but failed to predict the consistency with which certain types of behaviour are shown in stressful situations by a variety of species. Behavioural and physiological studies suggest that these behaviour patterns are closely associated with the incipient activation of sleep. The functional significance of this link and some of the causal processes which may be responsible for it are discussed. Paradoxically, however, displacement activities occur when animals are in a state of high arousal. The concept of arousal is reconsidered in the light of information theory and assumed to be closely correlated with the information processing rate in the nervous system. The relationships between neural and autonomic arousal are considered in this context. It is argued that over-arousal may occur when information handling exceeds the limited channel capacity of the system, with a consequent loss of efficiency. It is pointed out that there are mechanisms capable of controlling the information influx into the brain, and it is hypothesized that they are tied up in a feedback mechanism which regulates arousal and which involves the activation of a de-arousal system, corresponding to the neurological sleep mechanism. Displacement activities are viewed as consequences of this regulatory activation of the sleep system. This hypothesis is then compared with existing theories of displacement and its relationship with them is discussed.

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Zusammenfassung Die Arbeit erweitert eine neue Hypothese über die kausalen Mechanismen, die dem übersprungverhalten zugrunde liegen. Sie beginnt mit einer kritischen Übersicht der früher vorgeschlagenen Theorien und zeigt auf, daß diese nicht die Beständigkeit, mit der gewisse Verhaltensweisen von einer Anzahl von Tierarten in Stress-Situationen gezeigt werden, erklären. Verhaltens- und physiologische Studien deuten an, daß diese Verhaltensweisen in einem engen Zusammenhang mit einer partiellen Schlafaktivierung stehen. Die funktionelle Bedeutung dieses Zusammenhanges und die möglichen physiologischen Mechanismen, die dafür verantwortlich sein könnten, werden diskutiert. Paradoxerweise werden aber Übersprungsverhalten dann gezeigt, wenn sich Tiere in einem gesteigerten Wachzustand befinden. In diesem Zusammenhang wird das Arousal-Konzept im Lichte der Informationstheorie neu beleuchtet und es wird angenommen, daß der Arousal-Zustand eines Tieres im engen Zusammenhang mit der jeweiligen Informationsverarbeitungsrate im Nervensystem steht. Die Verhältnisse zwischen neuralem und autonomischen Arousal werden diskutiert. Es wird vorgeschlagen, daß sich Überarousal dann einstellt, wenn die Informationsverarbeitungsrate die Kanalkapazität des Systems übersteigt mit einem sich daraus ergebenen Wirkungsgradverlust. Es wird darauf hingewiesen, daß es Mechanismen gibt, die den Informationsfluß in das Gehirn regeln und angenommen, daß diese innerhalb eines Rückkopplungssystems funktionieren, welches Arousal reguliert. Diese Regelung benötigt die Aktivierung eines Arousal herabsetzenden Systems, das in den neurologischen Schlafmechanismen besteht. Das Auftreten von Übersprungsverhalten wird als eine Konsequenz dieser regulatorischen Aktivierung des Schlafsystems angesehen. Die Hypothese wird dann mit den vorhandenen Übersprungsverhaltenstheorien verglichen.

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The research underlying this paper has been supported by grants from the U.S. Air Force Office of Scientific Research through the European Office of Aerospace Research, the Science Research Council and the Royal Society to Professor N. Tinbergen, F. R. S. and myself. It was partly carried out at the Department of Zoology, Oxford. I am grateful to Dr. S. A. Hillyard who by revising an earlier version contributed much to whatever merits this paper has.     

Aspects of process diagnosis in the psychotherapy of psychosomatic diseases

15 patients with psychosomatic diseases and the phenomenon of alexithymia, together with neurotic patients are treated psychotherapeutically in half-open groups. Contrary to the neurotics the patients show some special features regarding the process diagnostics. In assessing the wished and really experienced nearness to the group members there is a deficient ability to differentiate. During the therapeutic process the intrapsychic tension (EMI - Inventory of Emotionalities) is subject to great fluctuations or doesn't change. The occurrence of fluctuations in the EMI and of greater differentiations in the N-D-Test (Nearness-Distance-Test) suggest a good prognosis. A therapy of psychosomatic patients together with neurotic patients seems to be more effective than the treatment in homogeneous groups.     

The diagnosis, epidemiology, and etiology of childhood schizophrenia

About half the Australian population of children who were functioning at a moderate or greater level of intellectual subnormality and who also presented schizophrenic behaviors were surveyed. From more than 300 such cases only 21 were confirmed as schizophrenic. Their average age was seven years eight months, four were girls, and eight had histories of normal physical health. Individual data were collected on antenatal and perinatal factors, childhood health, developmental progress, family history, physical characteristics, neurological signs, biochemical anomalies, and behavioral and psychiatric characteristics. These data sustained the hypotheses that the (a) incidence of the condition is slight, that (b) childhood schizophrenia is the result of a multicausal transactional process; that (c) there is a continuum from organic to functional conditions and that (d) the intellectual potential of these children is generally overrated.