Biomedical subjects

J Herder

Publications and source records attributed to J Herder.

9 recordsLinked to original sources

PubMed1996

A virtual reality interface to an intelligent dental care system.

The design and fabrication of teeth restorations in dentistry rely increasingly on CAD/CAM techniques. We present an approach for interactive design of the occlusal surface of teeth based on simulation of jaw articulation and computer-aided diagnosis of occlusal disorders. To bridge the cognitive gap between the dentist and the computer system, we propose a virtual reality user interface, which applies the metaphors of tools and techniques known in dentistry. This makes the restoration design more intuitive for dentists. The system uses Virtual Reality Modeling Language (VRML) and HTML standards to generate a treatment report and exchange data in an electronic form. The simulation of jaw articulation requires fast calculation of multi-point contacts and detection of collisions between surfaces of teeth and restorations. We have developed a distance maps technique which exhibits realtime performance for objects with complex geometry and is suitable for other virtual reality systems dealing with complex contacts. The characteristics of contacts between teeth acquired during lower jaw motion are compactly represented as accumulated distance maps. These maps are then used for automatic removal of interferences between the restorations and the opponent teeth, and provide the dentist with information for further manual adjustments of the occlusal surfaces.

Artificial Intelligence↗

PubMed1990

A factor analysis of Ellis' irrational beliefs.

In an effort to identify, organize, and operationally define the philosophies that underlie Albert Ellis' self-defeating beliefs, the authors factored an 11-item irrational-values self-report instrument given to 190 psychiatric patients. Four factors emerged and were named to reflect the contents of their items--"I need to control a dangerous world," "Self-assertion is painful," "I need affirmation," and "I lack control over my fate."

Humans↗

PubMed1989

The contributions of self-defeating philosophies, perceived helplessness, and repression to anxiety among psychiatric patients.

Four of the most influential psychological explanations for the development of anxiety attribute it to (1) repressed awareness of undesirable emotions; (2) the emergence of unacceptable feelings from the unconscious; (3) adherence to irrational, self-defeating philosophies; and (4) perceived helplessness/lack of control over one's affairs. To test these theories, the authors administered the Trait Anxiety, Denial, Irrational Beliefs, and Locus of Control scales to 190 psychiatric inpatients. Appropriate zero-order, attenuation-corrected, multiple, and partial correlations were run. Denial was correlated negatively with Trait Anxiety; this is consistent with the view that awareness of unpleasant emotions generates anxiety, but does not support the claim that it is the result of repression. The correlations of Trait Anxiety with the Irrational Beliefs scale were substantial. However, its relationships with Locus of Control were limited and nonsignificant after the effects of the Denial and Irrational Beliefs scales were removed statistically. The findings lend support to the positions that anxiety results from self-defeating philosophies and/or the emergence of unpleasant thoughts about oneself, but give only modest support to the "perceived helplessness" hypothesis and seem to contradict the "excessive repression" explanation.

Adjustment Disorders↗

PubMed1987

Intellectual deterioration and personality decompensation in schizophrenia.

The Army General Classification Test (AGCT) and the MMPI were administered to schizophrenic inpatients (N = 50) with initially high (mean standard score = 115) and low (77) intelligence at two timepoints separated by an average of 14 years. The Arithmetic scores of the more intelligent group declined significantly with time, but significant changes did not appear on the Vocabulary or Spatial Aptitude scores of that group. No significant mean changes appeared in the low-IQ sample. The high-IQ group's Arithmetic section deterioration resulted from an increased error rate, not a drop in speed. No changes beyond those attributable to chance appeared on the MMPI scales. The results suggest that an intellectual decline limited to certain skills and to a subset of subjects occurs in schizophrenia and that the deterioration is not attributable to personality decompensation as defined by the MMPI. Because these findings appear to contrast with most previous research in this area, they should be considered tentative until confirmed by independent studies.

Adult↗

PubMed1980

Effectiveness of alpha biofeedback therapy: negative results.

Assessed the utility of alpha biofeedback training in the treatment of psychiatric patients (N = 66). Biofeedback and placebo biofeedback groups were given alpha or mock-alpha training sessions, and their improvement on 54 variables was compared to that of no-treatment controls. Only a chance number of significant differential changes appeared among the three groups. A comparison of these negative results with an earlier study from our laboratory that had yielded positive findings suggested that clinical improvement in alpha biofeedback treatment may be the result of the relaxation training or special verbal instructions often incorporated into alpha training.

Adult↗

PubMed1979

Correlates of alpha, beta and theta wave production.

Studied the correlations of alpha, beta and theta time densities with psychological and psychophysiological variables in a psychiatric population (N = 76). The correlations of the EEG variables with measures of adjustment were small and barely exceeded chance expectations. Alpha and beta were correlated positively with pain threshold, while beta was related inversely to blood pressure. Theta was correlated positively with blood pressure and negatively with pulse rate. The implications of these findings for EEG biofeedback treatment were discussed.

Adult↗

PubMed1978

Alpha biofeedback therapy in alcoholics: an 18-month follow-up.

In an earlier study on patients with alcohol problems, an experimental group given 10 hour-long alpha biofeedback training sessions showed greater improvement on State and Trait Anxiety scores than did a control sample. In the present study an 18-month follow-up was done on those Ss. The differences between the experimentals and controls in State and Trait Anxiety after 18 months were essentially identical to the differences between them immediately after treatment, which indicates that alpha training had long-range therapeutic effects. A difference between the groups on the Alcohol Rehabilitation Followup Questionnaire also suggested that alpha training may have been associated with some reduction in alcohol consumption as well.

Adult↗

PubMed1977

Alpha wave biofeedback training therapy in alcoholics.

This investigation evaluated the therapeutic efficacy of alpha-wave biofeedback treatment for alcoholics. Twenty-five Ss were compared to a matched control group before and after administration of a 3-week alpha-wave biofeedback regimen on a wide variety of criteria that included State-Trait Anxiety, the MMPI, Multiple Affect Adjective Check List, Zuckerman's Sensation Seeking Scale, Watson's Anhedonia Scale, the Brief Psychiatric Rating Scale, and baseline alpha. The experimental Ss received 10 hour-long alpha training sessions. The experimentals showed more improvement than did controls on alpha production and two anxiety measure. Contradictory results appeared on two suspicion/paranoia measures. Alpha training appeared useful in the treatment of anxiety, but not other problems. However, the absence of significant correlations between amount of change on alpha and the anxiety measures suggests that the improvement may be due to a placebo effect.

Adult↗

PubMed1976

The effects of cerebral electric therapy (electrosleep) on anxiety, depression, and hostility in psychiatric patients.

The effects of cerebral electric therapy (electrosleep) and placebo on self-ratings of anxiety, depression, and hostility were compared. No difference in the amount of improvement shown by the two groups appeared on any of the five measures employed, although a major placebo effect was evident on all of the criteria. The results argue against the use of electrosleep as a treatment for these symptoms except when it may be employed for its placebo value.

Adult↗