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Biomedical subjects

A T Pope

Publications and source records attributed to A T Pope.

5 recordsLinked to original sources
PubMed2000

A closed-loop system for examining psychophysiological measures for adaptive task allocation.

A closed-loop system was evaluated for its efficacy in using psychophysiological indexes to moderate workload. Participants were asked to perform either 1 or 3 tasks from the Multiattribute Task Battery and complete the NASA Task Load Index after each trial. An electroencephalogram (EEG) was sampled continuously while they performed the tasks, and an EEG index (beta/alpha plus theta) was derived. The system made allocation decisions as a function of the level of operator engagement based on the value of the EEG index. The results of the study demonstrated that it was possible to moderate an operator's level of engagement through a closed-loop system driven by the operator's own EEG. In addition, the system had a significant impact on behavioral, subjective, and psychophysiological correlates of workload as task load increased. The theoretical and practical implications of these results for adaptive automation are discussed.

Adaptation, Psychological↗
PubMed1996

On the interaction of hypnotizability and negative affect in chronic pain. Implications for the somatization of trauma.

The high risk model of threat perception predicts that high hypnotizability is a risk factor for trauma-related somatization. It is hypothesized that high hypnotizability can increase experimentally induced threat or negative affect, as measured by skin conductance level, in a linear or dose-response manner. This hypothesized interaction of hypnotic ability and negative affect was found in a consecutive series of 118 adult patients with chronic pain symptoms. Larger increases in skin conductance levels during cognitive threat were significantly related to higher levels of hypnotizability. In addition, individuals with high hypnotizability retained higher skin conductance levels than individuals with low hypnotizability after stress. The clinical implications of the interaction of hypnotizability and negative affect during threat perception and delayed recovery from threat perception are discussed in terms of cognitive mechanisms in the etiology and therapy of trauma-related dissociative disorders.

Adaptation, Psychological↗
PubMed1995

Biocybernetic system evaluates indices of operator engagement in automated task.

A biocybernetic system has been developed as a method to evaluate automated flight deck concepts for compatibility with human capabilities. A biocybernetic loop is formed by adjusting the mode of operation of a task set (e.g., manual/automated mix) based on electroencephalographic (EEG) signals reflecting an operator's engagement in the task set. A critical issue for the loop operation is the selection of features of the EEG to provide an index of engagement upon which to base decisions to adjust task mode. Subjects were run in the closed-loop feedback configuration under four candidate and three experimental control definitions of an engagement index. The temporal patterning of system mode switching was observed for both positive and negative feedback of the index. The indices were judged on the basis of their relative strength in exhibiting expected feedback control system phenomena (stable operation under negative feedback and unstable operation under positive feedback). Of the candidate indices evaluated in this study, an index constructed according to the formula, beta power/(alpha power + theta power), reflected task engagement best.

Adult↗
PubMed1982

Neuroleptic-like electroencephalographic changes in schizophrenics through biofeedback.

Nine schizophrenic patients participated in a study which explored whether EEG feedback techniques could effect changes in the EEG similar to those associated with neuroleptic-induced improvement. During five sessions, each patient was presented feedback signals which continuously reflected the discrepancy between characteristics of the patient's EEG power spectral profile and spectral profile characteristics associated by past research with neuroleptic induced clinical improvement. Significant within-session changes were observed for two of three EEG power spectrum bands of interest. No significant session-to-session EEG changes were observed. The results suggest that the EEG of schizophrenics can be temporarily altered, using feedback techniques, in a way that mimics the EEG changes that have been shown to occur with neuroleptic induced clinical improvement.

Antipsychotic Agents↗