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Biomedical subjects

Herta Flor

Publications and source records attributed to Herta Flor.

At least 73 records · Page 4Linked to original sources
PubMed2002

The role of operant conditioning in chronic pain: an experimental investigation.

The role of operant conditioning for the development and maintenance of chronic pain was examined in 30 chronic back pain patients (CBP) and 30 matched healthy controls. Half of each group was reinforced for increased, half for decreased pain reports while EEG, EOG, heart rate, skin conductance and muscle tension levels were recorded. Both groups showed similar learning rates, however, the CBP patients displayed slower extinction of both the verbal and the cortical (N150) pain response. In addition, the CBP group displayed prolonged elevated electromyogram levels to the task. These data suggest that CBP patients are more easily influenced by operant conditioning factors than healthy controls and this susceptibility may add to the maintenance of the chronic pain problem.

Adult↗
PubMed2002

Pavlovian conditioning of opioid and nonopioid pain inhibitory mechanisms in humans.

Learning processes such as respondent or Pavlovian conditioning are believed to play an important role in the development of chronic pain, however, their influence on the inhibition of pain has so far not been assessed in humans. The purpose of this study was the demonstration of Pavlovian conditioning of stress-induced analgesia in humans and the determination of its opioid mediation. In a differential classical conditioning paradigm two different auditory stimuli served as conditioned stimuli and mental arithmetic plus white noise as unconditioned stimulus. Subsequent to four conditioning trials naloxone or placebo was applied in a double-blind fashion on two test days. Both pain threshold and pain tolerance showed conditioned stress-induced analgesia. Pain tolerance was affected by naloxone whereas pain threshold was not. The data of this study show that stress analgesia can be conditioned in humans and that it is at least partially mediated by the endogenous opioid system. Learning processes also influence pain inhibitory processes in humans and this effect might play a role in the development of chronic pain.

Adult↗
PubMed2002

Phantom-limb pain: characteristics, causes, and treatment.

Phantom-limb pain is a common sequela of amputation, occurring in up to 80% of people who undergo the procedure. It must be differentiated from non-painful phantom phenomena, residual-limb pain, and non-painful residual-limb phenomena. Central changes seem to be a major determinant of phantom-limb pain; however, peripheral and psychological factors may contribute to it. A comprehensive model of phantom-limb pain is presented that assigns major roles to pain occurring before the amputation and to central as well as peripheral changes related to it. So far, few mechanism-based treatments for phantom-limb pain have been proposed. Most published reports are based on anecdotal evidence. Interventions targeting central changes seem promising. The prevention of phantom-limb pain by peripheral analgesia has not yielded consistent results. Additional measures that reverse or prevent the formation of central memory processes might be more effective.

Humans↗
PubMed2002

Aversive Pavlovian conditioning in psychopaths: peripheral and central correlates.

Differential aversive Pavlovian conditioning with a foul odor as unconditioned stimulus (US) and neutral faces as conditioned stimuli (CS) was compared between 9 noncriminal psychopaths as defined by the Hare Psychopathy Checklist Revised and 12 healthy controls. Event-related potentials (ERP), heart rate, skin conductance response, corrugator EMG, and startle response potentiation as well as valence, arousal, and contingency of the CS were assessed. Whereas the healthy controls (HC) showed significant CS +/CS- differentiation, the psychopaths (PP) failed to exhibit a conditioned response although unconditioned responses were comparable between the groups. N100, P200, and P300 to the CSs revealed that psychopaths were not deficient in information processing and showed even better anticipatory responding than the HC group indicated by the terminal contingent negative variation (tCNV), that lacked, however, CS+ and CS- differentiation. These data indicate a deficit in association formation in psychopaths that may be related to deficient interaction of limbic-subcortical and cortical structures.

Adult↗
PubMed2002

Reproducibility and stability of neuroelectric source imaging in primary somatosensory cortex.

The present study investigated the test-retest reliability of EEG source localization of somatosensory evoked potentials (SEPs) over an extended time period and tested the accuracy of source reconstruction co-registred with individual brain morphology (MRIs). Seven healthy subjects were stimulated pneumatically at the first digit and fifth digit of each hand and at the left and right lower corner of the mouth in two sessions spaced several weeks apart. At each location 1000 stimuli were presented. The overlay of the dipole localizations with the individual anatomic structure of the subjects' cortex was accomplished by the use of magnetic resonance images. A spherical 4-shell model of the head was used to localize the neuroelectric sources of the EEG data. In two cases a more realistically shaped 3 compartment model was computed using the boundary element method (BEM). The source localizations of the SEP component were found to be highly reproducible: the mean standard deviation of the dipole locations was 5.21 mm in the x-, 5.98 mm in the y- and 4.22 mm in the z-direction. BEM was not found to be superior to a 4-shell model. These data support the use of multi-electrode EEG recordings combined with MRI as an adequate method for the investigation of the functional organization of the somatosensory cortex.

Adult↗
PubMed2002

The modification of cortical reorganization and chronic pain by sensory feedback.

Recent neuroscientific evidence has revealed that the adult brain is capable of substantial plastic change in areas such as the primary somatosensory cortex that were formerly thought to be modifiable only during early experience. We discuss research on phantom limb pain as well as chronic back pain that revealed functional reorganization in both the somatosensory and the motor system in these chronic pain states. In phantom limb pain patients, cortical reorganization is correlated with the amount of phantom limb pain; in low back pain patients the amount of reorganizational change increases with chronicity. We present a model of the development of chronic pain that assumes an important role of somatosensory pain memories. In phantom limb pain, we propose that those patients who experienced intense pain prior to the amputation will later likely develop enhanced cortical reorganization and phantom limb pain. We show that cortical plasticity related to chronic pain can be reduced by behavioral interventions that provide feedback to the brain areas that were altered by somatosensory pain memories.

Biofeedback, Psychology↗
PubMed2002

Reliability and validity of neuroelectric source imaging in primary somatosensory cortex of human upper limb amputees.

The present study investigated the test-retest reliability of EEG source localizations of somatosensory evoked potentials (SEPs) in human upper limb amputees over a long time frame (several months) and examined the validity of source reconstruction. In two sessions spaced several months apart five unilateral upper limb amputees were stimulated at the first and fifth digit of the intact hand and at the left and right lower corner of the mouth. To examine the validity of the results of the neuroelectric source reconstruction a comparison with neuromagnetic source localization was performed for two subjects. The source localizations of the SEP components were found to be highly reproducible: the mean standard deviation of the dipole locations was 8.80 mm in the x-, 7.00 mm in the y- and 4.15 mm in the z-direction. The match of the comparison of EEG and MEG data was in the range of one centimeter. These results support the use of multi-electrode EEG recordings combined with MRI as an adequate method for the investigation of the functional organization of the somatosensory cortex in upper limb amputees and suggest high stability of cortical reorganization in these subjects.

Adult↗
PubMed2002

[Posttraumatic stress disorder and trauma memory--a psychobiological perspective].

We postulate that posttraumatic stress disorder is maintained by learnt cortical and subcortical plastic changes. Specifically, we assume that classical conditioning leads to an intense emotional memory of the trauma that is mainly implicit and related to plastic changes in subcortical structures such as the amygdala. At the same time an insufficient explicit trauma memory is formed that manifests itself in insufficient cortical processing of trauma content. This dissociation of implicit and explicit memory prevents the extinction of the emotional response to the trauma and perpetuates the disorder. First empirical results based on this model confirm the main hypotheses.

Amygdala↗
PubMed1997

Processing of pain- and body-related verbal material in chronic pain patients: central and peripheral correlates.

The processing of pain-related, body-related and neutral words was assessed in chronic pain patients and matched healthy controls. During and after word presentation at perception threshold, electromyographic activity (EMG), heart rate, skin conductance level and electroencephalographic (EEG) data from 11 electrode sites were recorded. Startle responses were measured to suprathreshold word stimuli. Although the patients did not recognize more pain-related words, they produced an enhanced left-hemispheric N100 and N200 to pain-related as compared to neutral words. In addition, the patients did not show a distinct P300 but a continuous positive shift to all words extending into the 800-ms range. Skin conductance levels to the pain-related words were also enhanced in patients only. These data partially support the notion of pain-related implicit memory structures in the brain of chronic pain patients that may selectively draw attention to pain-related stimuli and may thus enhance pain perception.

Adult↗
PubMed1992

Efficacy of multidisciplinary pain treatment centers: a meta-analytic review.

Sixty-five studies that evaluated the efficacy of multidisciplinary treatments for chronic back pain were included in a meta-analysis. Within- and between-group effect sizes revealed that multidisciplinary treatments for chronic pain are superior to no treatment, waiting list, as well as single-discipline treatments such as medical treatment or physical therapy. Moreover, the effects appeared to be stable over time. The beneficial effects of multidisciplinary treatment were not limited to improvements in pain, mood and interference but also extended to behavioral variables such as return to work or use of the health care system. These results tend to support the efficacy of multidisciplinary pain treatment; however, these results must be interpreted cautiously as the quality of the study designs and study descriptions is marginal. Suggestions for improvement in research designs as well as appropriate reports of research completed are provided.

Adult↗
PubMed1991

Stress-related electromyographic responses in patients with chronic temporomandibular pain.

Surface electromyographic (EMG) recordings from the right and left masseter and the left biceps muscle during stress and non-stress imagery were obtained from patients with temporomandibular myofascial pain and dysfunction syndrome (MPDS), temporomandibular joint disorder (TMJD), chronic low back pain (CBP) and healthy controls (HC). Both the MPDS and the TMJD groups displayed significantly more masseter EMG reactivity to the stressful imagery than the CBP and HC groups. The 2 dental groups did not differ significantly from each other. The MPDS patients indicated more life stress and gave higher aversiveness ratings during the experiment. These findings are discussed with respect to the validity of the TMJD and MPDS distinction.

Adolescent↗
PubMed1989

Relationship of pain impact and significant other reinforcement of pain behaviors: the mediating role of gender, marital status and marital satisfaction.

The operant perspective of chronic pain emphasizes the important role of reinforcement contingencies in the maintenance of pain behaviors and the experience of pain. Patients' 'significant others' are viewed as primary reinforcing agents. The relationship between pain intensity, interference, and responses by significant others in maritally distressed, maritally satisfied, and unmarried samples of male and female pain patients and their significant others was examined in this study. Results revealed that only for married male patients significant other responses explained significant proportions of the variance in the impact of pain. Significant other responses failed to explain significant proportions of the variance for male patients living with non-married significant others. By way of contrast, for female patients pain impact and reinforcement variables were less highly associated in the married as compared to the unmarried patients. For both males and females, there were significantly higher correlations between significant other responses and pain impact levels for the maritally satisfied patients. These results provide qualified support for the operant formulation of the importance of reinforcement of pain behaviors by significant others, however, these responses appear to be dependent upon gender, marital status, and marital satisfaction. Thus, clinicians need to give greater attention to these variables when designing treatment plans.

Adult↗
PubMed1987

Pain and families. I. Etiology, maintenance, and psychosocial impact.

This is the first part of a two-part extended review on the interdependency between chronic pain and families. This paper will address the role of the family in the etiology and maintenance of chronic pain and will describe the reciprocal impact of chronic pain on families. Different conceptualizations of the role of the family and the available empirical evidence related to 3 central questions, namely, 'do families play an etiological role in chronic pain?,' 'does the family maintain the chronic pain problem?,' and 'is there a negative impact of chronic pain on the family?' will be critically examined. The second, companion paper will address the issue of the inclusion of family members in the assessment and treatment of chronic pain. Finally, recommendations for future research will be made.

Adaptation, Psychological↗
PubMed1987

Pain and families. II. Assessment and treatment.

This is the second part of an extended review on pain and families. The first paper dealt with the role of the family in the etiology and maintenance of chronic pain and discussed the impact of chronic pain on families. The paper will examine the role of the family in the assessment and treatment of chronic pain. Finally, problems of the theoretical models and empirical studies reviewed will be discussed and suggestions for future research will be presented.

Adaptation, Psychological↗
PubMed1987

Pain greater than pain behaviors: the utility and limitations of the pain behavior construct.

A great deal of attention has been given to the importance of learning factors in communications of pain and suffering--pain behaviors. The concept of pain behaviors has served a heuristic function, however, there remain a number of important questions to be answered regarding the assessment and conceptual limitations of the construct. These concerns and questions must be acknowledged if the construct is to be of use in enhancing our understanding of chronic pain syndromes and to be employed in treatment. Current conceptualizations of pain behaviors are examined and methods of assessing pain behaviors are evaluated. The validity and utility of the construct and its limitations are discussed. It is concluded that failure to consider psychosocial, psychophysiological, and medical-physical factors may lead to an inadequate understanding of the patient and results in inappropriate treatment interventions. Suggestions for refined understanding of the scope of the construct are provided.

Chronic Disease↗
PubMed1986

Long-term efficacy of EMG biofeedback for chronic rheumatic back pain.

Short-term effects of EMG biofeedback for chronic rheumatic back pain have been documented, however, the long-term efficacy of this treatment modality has not yet been established. Twenty-two patients of an original sample of 24 patients who participated in a treatment outcome study [6] were followed up 2.5 years after they had been treated with either EMG biofeedback, pseudotherapy, or conventional medical treatment alone. The results indicate that patients treated with EMG biofeedback maintained beneficial effects and differ significantly from the control groups both on behavioral and cognitive responses to the pain, but not global pain intensity ratings. These data support the long-term utility of biofeedback for chronic rheumatic back pain.

Adult↗
PubMed1984

Etiological theories and treatments for chronic back pain. II. Psychological models and interventions.

This is the second part of an extended review of the etiology and treatment of chronic back pain (CBP). The first paper dealt with somatic factors and interventions, this paper will examine psychological theories on the etiology of CBP and psychological treatments for CBP. Finally common problems of both the somatic and the psychological approaches will be discussed and suggestions for treatment and research will be made.

Back Pain↗