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At least 1,693 records · Page 94Linked to original sources
PubMed2005

Characteristic changes in the physiological components of cybersickness.

We investigated the characteristic changes in the physiology of cybersickness when subjects were exposed to virtual reality. Sixty-one participants experienced a virtual navigation for a total of 9.5 min, and were required to detect specific virtual objects. Three questionnaires for sickness susceptibility and immersive tendency were obtained before the navigation. Sixteen electrophysiological signals were recorded before, during, and after the navigation. The severity of cybersickness experienced by participants was reported from a simulator sickness questionnaire after the navigation. The total severity of cybersickness had a significant positive correlation with gastric tachyarrhythmia, eyeblink rate, heart period, and EEG delta wave and a negative correlation with EEG beta wave. These results suggest that cybersickness accompanies the pattern changes in the activities of the central and the autonomic nervous systems.

Adult↗
PubMed1990

An implantable neurocybernetic prosthesis system.

The neurocybernetic prosthesis (Cyberonics, Inc.) is an implantable, multiprogrammable pulse generator that delivers constant current electrical signals to the vagus nerve for the purpose of reducing the frequency and/or severity of epileptic seizures. The device is implanted in a subcutaneous chest pocket just below the clavicle, similar to cardiac pacemaker placement. The stimulation signal is transmitted from the prosthesis to the vagus nerve through a stimulation lead. The prosthesis can be programmed using any IBM-compatible personal computer with programming software and a programming wand. The electrodes used in the first group of patients were found to break at an unacceptable rate. Design modifications appear to have resolved this problem.

Animals↗
PubMed1990

Efficacy and safety of vagus nerve stimulation in patients with complex partial seizures.

A clinical trial of chronic intermittent vagal stimulation in five patients suggests that the procedure may be safe and effective as adjunctive treatment of medically intractable seizures of partial onset. Patients tolerated well the implantation of the neurocybernetic prosthesis and the vagal stimulation without serious physiological or lifestyle changes. Stimulation of the vagus nerve either reduced the seizure frequency or decreased the duration or intensity of seizures. Adverse side effects were limited to a tingling sensation in the throat and hoarseness during stimulation. A major complication was mechanical interruption of the wire-electrode circuitry, with consequent cessation of stimulation. The small number of patients and the relatively short follow-up period make this a pilot study, but the results are promising.

Adult↗
PubMed1990

Vagus nerve stimulation in humans: neurophysiological studies and electrophysiological monitoring.

Evidence from studies of experimental animals indicates that electrical stimulation of the vagus nerve alters behavioral and electrographic seizure activity. We report on effects of electrical stimulation of the vagus nerve in five patients with medically intractable seizures as part of a clinical trial of chronic vagal stimulation for control of epilepsy. The mechanism of action of the vagal antiepileptic effect is unknown, and it is hoped that analysis of electrophysiological effects of vagal nerve stimulation will help elucidate which brain areas are affected. Stimulation of the left vagus nerve in the neck was accomplished with a programmable implanted stimulator. Effects of stimulus amplitude, duration, and rate were studied. Noncephalic reference recording of the vagus-nerve-evoked potential showed some unusual properties: a scalp negative component occurred with latency of 12 ms, very high amplitude (up to 60 microV), and widespread scalp distribution. Field distribution studies indicate that this potential is generated in the neck, in the region of the stimulating electrodes. Muscle paralysis confirms this observation. Stimulation at various frequencies had no noticeable effect on electroencephalographic (EEG) activity regardless of whether the patient was under general anesthesia, awake, or asleep.

Adult↗
PubMed1991

The implantable neurocybernetic prosthesis system.

The neurocybernetic prosthesis system (NCP) is an implantable, multiprogrammable pulse generator that delivers constant current electrical signals to the vagus nerve for the purpose of reducing the frequency and severity of epileptic seizures. The signals are delivered on a predetermined schedule, or may be initiated by the patient with an external magnet. The device is implanted in a subcutaneous pocket in the chest just below the clavicle, similar to pacemaker placement. The stimulation signal is transmitted from the prosthesis to the vagus nerve through a lead connected to an electrode which is a multi-turn silicone helix, with a platinum band on the inner turn of one helix. The prosthesis can be programmed with any IBM- compatible personal computer using NCP software and a programming wand.

Cybernetics↗
PubMed1991

Vagal stimulation for control of complex partial seizures in medically refractory epileptic patients.

Chronic intermittent stimulation of the vagus nerve is a new method currently being tested for the treatment of medically intractable complex partial seizures (CPS). We have studied the effects of vagal stimulation in nine patients with CPS for 4-16 months to determine its safety and efficacy. With the patients maintained on constant dosages of antiepileptic drugs, we recorded the electroencephalogram and electrocardiogram, and performed clinical laboratory tests and gastric analysis over a 6-week baseline period. The neurocybernetic prosthesis (NCP) was then implanted and connected to two spiral electrodes wound around the left vagus nerve. After a 4-week placebo period, vagal stimulation was started. Stimulation parameters were increased stepwise at monthly intervals until patients were being stimulated for 30-second periods at 20-50 Hz with 1-2 mA of current at 250-500 microseconds pulses. A second 4-week placebo period was added 3 months after the implantation. Thereafter, vagal stimulation was resumed and self-stimulation with magnetic activation was allowed for a 1-minute period at the onset of an aura. Six patients had a significant reduction in the frequency, intensity, or duration of seizures. All patients tolerated the implantation and stimulation well and none reported pain, discomfort, or important changes in their daily activities, sleep habits, eating, swallowing, or breathing. There were no remarkable changes in blood pressure or heart rate.

Adult↗
PubMed1977

The family interactional perspective: a study and examination of the work of Don D. Jackson.

This article presents an overview of the primary contributions of the late Don D. Jackson. It analyzes and attempts to unify the central concepts of what the first referred to as "conjoint family therapy." Emphasis in upon the theoretical components leading to the development of a behaviorally oriented, nontransference, focused-treatment format, labeled by the author as "family interactional psychotherapy."

Behavior Therapy↗
PubMed1982

Beyond homeostasis: toward a concept of coherence.

The concept of homeostasis has served as a major building block, if not the cornerstone, of family theory and family therapy. Designed to account for the perceived stability of systems (and symptoms), homeostasis is an epistemologically flawed concept that has repetitively been used in the service of dualistic, animistic, and vitalistic interpretations of systems. Accordingly, homeostasis has led to quirky clinical formulations and a great deal of fuzzy theorizing. This paper contends that the notion of homeostasis is fundamentally inconsistent with systemic epistemology and should be replaced with the more compatible concept of coherence. Whereas homeostasis is a heuristic concept that is not part of a more encompassing theory, the concept of coherence is inseparable from the epistemology in which it is embedded.

Cybernetics↗
PubMed1982

Some conceptual distinctions are more useful than others.

Useful distinctions in conceptual schemes lead to explanatory or descriptive metaphors that have a clear form. Muddles, on the other hand, are created when useful distinctions that could be drawn are not or when an unnecessary distinction is drawn. The field of family therapy, now involved in an explicit epistemological and paradigmatic shift, has various muddles of each kind. The purpose of this essay is to describe some of these muddles and to suggest that making a distinction between "the study of the family-as-a-system" and "the study of family-therapy-as-a-system" leads to some useful and clear metaphors.

Communication↗