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Biomedical subjects

R J Gatchel

Publications and source records attributed to R J Gatchel.

At least 91 records · Page 5Linked to original sources
PubMed1985

Quantification of lumbar function. Part 4: Isometric and isokinetic lifting simulation in normal subjects and low-back dysfunction patients.

The present study collected the first normative data on a new dynamic isokinetic lifting device and compared a normal subject sample (n = 65) with a chronic low-back pain patient sample (n = 68) on this device. In addition, a comparison was made between isometric lifting measures collected for these controls and patients, and a normative industrial sample used in an earlier isometric testing protocol. Results demonstrated significant differences between controls and patients on all measures. An unanticipated finding was the greater lifting capacity levels of the present normal sample relative to those reported in the earlier isometric testing. These findings demonstrate that dynamic lifting simulation offers an important new tool for medical and industrial assessment, and conservative medical management.

Adult↗
PubMed1985

Quantification of lumbar function. Part 1: Isometric and multispeed isokinetic trunk strength measures in sagittal and axial planes in normal subjects.

The goals of this study were to: evaluate the repeatability of a method of measuring trunk strength; measure isometric and isokinetic strength of trunk flexors, extensors and rotators; explore relationships among these muscle groups; and compare a torque to body weight adjustment measure versus lean body weight. One hundred twenty-five normal subjects (62 males, 63 females) were tested using a Cybex prototype trunk extension-flexion system. Sixty-seven subjects (25 males, 42 females) were tested using a prototype torso rotation unit. Fifty were tested on both devices. Results demonstrated that the strength data were reliable, with strength being greatest in extension. The following were also learned-torque output declined slightly with increased speed; extensor-flexor strength remained consistent from 18 to 44 years; extension-flexion ratios exceeded 1.1:1; left to right rotation ratios remained 1:1; there was no significant difference between torque adjusted to body weight or to lean body weight.

Adult↗
PubMed1984

Behavioral and biochemical effects of job loss and unemployment stress.

Previous research on the effects of unemployment has focused upon both anticipation of job loss and long-term unemployment, typically using self-report and some biochemical measures of response to unemployment stress. The present study was concerned with behavioral and biochemical responses to unemployment. It was also designed to examine a somewhat different time course of unemployment than has been used in previous work. Results indicated that stress accompanies unemployment; looking at people who had been unemployed for up to four months, those who had been unemployed for greater lengths of time performed more poorly on a behavioral task and exhibited higher levels of urinary norepinephrine and epinephrine than did persons unemployed for shorter time periods or subjects who were employed.

Adult↗
PubMed1983

The prevalence of dental fear and avoidance: a recent survey study.

This study evaluates the current incidence of dental fear and avoidance in the general population. A telephone survey, using a random dialing procedure, was used as a means of data collection. Results indicated that 11.7% of the respondents reported high dental fear, and another 17.5% reported moderate dental fear. Results also disclosed that 36.5% of those surveyed had not been to the dentist in over a year. Approximately 15.5% of the respondents surveyed had some degree of dental fear and were dental avoiders (using the criterion of no dental visitation for at least one year). These findings highlight the fact that additional attention and research efforts still need to be dedicated to dealing with the highly fearful and avoidant dental patient.

Adult↗
PubMed1982

Psychophysiological and cognitive characteristics of ulcer and rheumatoid arthritis patients.

This study examined differences in the physiological and cognitive response patterns among peptic ulcer, rheumatoid arthritis, and healthy group subjects to two types of stressors-slides of autopsies and imagined scenes involving conflicts and attitudes proposed to be associated with the two psychosomatic disorders. Ten subjects were assessed in each group. Results indicated that the ulcer patients demonstrated a heart rate accelerative trend, while arthritic and normal subjects showed significant deceleration, in response to the aversive slides of autopsies. Ulcer patients also reported paying less attention to the slides, and experiencing more anxiety when viewing them, relative to the other subjects. In response to the imagined scenes, the arthritic patients responded with more heart rate acceleration, apparently because of the greater emotional imagery produced by the scenes in these subjects. Finally, self-report and interview data did not lend support to a derivative of the specificity-of-attitude model of psychosomatic disorders.

Adult↗
PubMed1982

The comparative effectiveness of heart rate biofeedback, speech skills training, and a combination of both in treating public-speaking anxiety.

Forty-two speech-anxious undergraduate students (21 female, 21 male) were administered either heart rate biofeedback training, speech skills training, or a combination of both to aid in the alleviation of speech anxiety. Physiological (heart rate, tonic skin conductance level, systolic blood pressure, and diastolic blood pressure), overt motor, and self-report measures of anxiety were assessed during a pretreatment speech and two posttreatment speeches. Results indicated that all treatments were effective in lowering overt motor and self-report components of anxiety. However, only the biofeedback and combined group subjects demonstrated significantly less heart rate increase while speaking before an audience during the posttreatment assessment. Two individual difference variables examined in this study--cognitive/autonomic focus of anxiety and subjective confidence in treatment--were not found to significantly influence treatment effectiveness. Finally, factor analyses of the physiological data suggested that heart rate changes play a large role in the physiological component of anxiety.

Anxiety↗
PubMed1982

Mediating influences of social support on stress at Three Mile Island.

Symptom reporting, task performance, and urinary catecholamine excretion were studied in a group of people living near the Three Mile Island nuclear power plant and in control populations. More than a year after the accident, living near the damaged reactor was associated with elevations in all indices of stress compared with control levels. Social support mediated these stress indices such that higher levels were associated with fewer psychological and behavioral symptoms of stress. Biochemical measures showed a different pattern of results.

Analysis of Variance↗
PubMed1981

The role of biofeedback in the operant modification of human heart rate.

The recent literature on the role played by biofeedback in the modification of human heart rate is reviewed. Emphasis is placed on research pertinent to the issue of whether biofeedback is more productively conceived as a reinforcer of an operant response or as a source of information enabling the development of a voluntary motor skill. Criticisms of the operant paradigm are answered, and limitations of the motor skills analogy are discussed. It is concluded that the operant conditioning paradigm best accounts for most available data on the role of biofeedback in heart rate control, and that it is superior to the motor skills model because it is more parsimonious and makes fewer untestable assumptions.

Biofeedback, Psychology↗
PubMed1980

The production and generalization of large-magnitude heart rate deceleration by contingently faded biofeedback.

Eight subjects were taught to decrease their heart rates via biofeedback training. Four of these received contingently faded, beat-by-beat analogue feedback and contingent reinforcement each time their performance met a specified and adjusting criterion. The other four received continuous, beat-by-beat analogue feedback, but not the contingent reinforcement. Subjects in the two groups were yoked to ensure equal densities of reinforcement. Subjects in the first group were asked to decrease heart rates 15% from baseline and were then trained using only 75%, 50% and 25% of beat-by-beat feedback. It was hypothesized that the immediate reinforcement of appropriate behavior and the contingent fading (following mastery) of feedback would aid in the generalization of the response. Following completion of all criterion steps or 10 training sessions, whichever came first, all subjects were tested with no feedback and no contingent reinforcement. The group receiving contingently faded feedback training showed a significantly greater heart rate decrease in the training sessions and also the test session. These results were interpreted as indicating that biofeedback can be conceptualized as an operant conditioning paradigm, and that the use of operant techniques may help subjects produce clinically significant changes.

Biofeedback, Psychology↗
PubMed1979

EEG and autonomic responding to verbal, spatial and emotionally arousing tasks: differences among adults, adolescents and inhalant abusers.

The present study investigated the physiological responses of an adolescent inhalant abuse group, an adolescent non-abuse group, and an adult non-abuse group elicited by three types of tasks: verbal, spatial, and emotionally arousing. Each group consisted of 10 male Mexican-American subjects. Bilateral EEG and electrodermal activity, as well as heart rate, were monitored. While exploring for possible heart rate and hemispheric alpha wave differences in response to predominantly verbal and spatial tasks, an attempt was also made to discover if electrodermal responses could be bilaterally differentiated. Another purpose of the study was to explore possible psychophysiological differences between a younger and older group, and between an inhalant abusing group and a non-abuse group, in response to the three types of tasks. Results indicated that attempts to produce task-related EEG hemispheric asymmetry were largely nonsuccessful. Bilateral electrodermal responses were also not greatly differentiated. It was suggested that stronger task manipulations were needed. Significant group differences were found for initial physiological response levels (adults demonstrated higher levels than the two adolescent groups) and for heart rate response to the emotionally arousing task (non-abusing subjects demonstrated greater heart rate acceleration than inhalant abusing subjects). It was suggested that group differences in initial levels occurred due to the adult groups's greater involvement in the experimental situation. Heart rate differences to the emotionally arousing situation were discussed in terms of Zuckerman's sensation seeking hypothesis.

Adolescent↗
PubMed1979

Development of physiological response patterns concomitant with the learning of voluntary heart rate control.

Thirty-six male undergraduate students were instructed to raise or lower heart rate in a multiple-session biofeedback experiment. Systolic and diastolic blood pressure, frontalis electromyographic activity, and skin conductance level were simultaneously recorded throughout biofeedback training. Principal axes factor analyses showed that physiological response patterning concomitant with the development of heart rate control was different early in training (Training Session 1) than it was late in training (Training Session 4) for both speeding and slowing conditions. These results indicate that different heart rate control strategies were used by the subjects early and late in training. The factor patterns also indicated a tendency for greater heart rate response specificity as training progressed for both speeding and slowing. Heart rate speeding sessions were also found to be associated with a significant increase in perceived state anxiety as measured by the State-Trait Anxiety Inventory. No significant change in perceived anxiety state, however, was associated with heart rate slowing.

Adolescent↗
PubMed1978

Physiological response patterning in short--and long--term heart rate control training.

The present investigation assessed the physiological response patterns which accompany heart-rate control performance, both early and late in training. Six subjects were employed who received six heart-rate control training sessions, half of which were speeding sessions and half of which were slowing. Heart rate, skin resistance, frontalis EMG, systolic and diastolic blood pressure, and respiration rate were continuously recorded throughout all training sessions. Results indicated that the physiological response topography during heart-rate control performance changes from early to late training. Moreover, the changes are different for speeding and slowing performance, suggesting the involvement of different underlying physiological mechanisms in the two tasks.

Adolescent↗