Biomedical subjects

Karin Roelofs

Publications and source records attributed to Karin Roelofs.

12 recordsLinked to original sources

PubMed2006

The effects of social stress and cortisol responses on the preconscious selective attention to social threat.

The purpose of the present study was to investigate the effects of social stress and stress-induced cortisol on the preconscious selective attention to social threat. Twenty healthy participants were administered a masked emotional Stroop task (comparing color-naming latencies for angry, neutral and happy faces) in conditions of rest and social stress. Stress was induced by means of the Trier social stress test. Based on the stress-induced increase in cortisol levels, participants were allocated post hoc (median-split) to a high and low responders group. In contrast to low responders, high responders showed a negative or avoidant attentional bias to threat (i.e. shorter latencies for angry than neutral faces) in the rest condition. Most importantly, although low responders became avoidant, the high responders became vigilant to the angry faces after stress induction. There were no such effects for happy faces. Our findings are in line with previous studies in both animals and humans, that associate high glucocorticoid stress-responsiveness with diminished avoidance and prolonged freezing reactions during stress.

Adolescent↗

PubMed2006

Motor and sensory dissociative phenomena associated with induced catalepsy: A brief communication.

The purpose of this study was to investigate dissociative symptoms that may occur as an epiphenomenon of tactile-induced catalepsy. In 15 participants, catalepsy was induced in the right arm, and dissociative symptoms were evaluated using a self-report questionnaire. In comparison with the left, noncataleptic arm, the right cataleptic arm was perceived differently. In addition to increased rigidity, the cataleptic arm was characterized by the presence of paresthesias, a decreased perception of sense and a decreased awareness of the arm. Moreover, the self-reported changes in perception were significantly correlated to the hypnotically induced arm-immobilization part of the Stanford Hypnotic Susceptibility Scale. In conclusion, catalepsy induction elicits a variety of dissociative symptoms and provides a useful research paradigm for the study of motor-perceptual dissociative phenomena.

Adult↗

PubMed2005

Hyperactive action monitoring during motor-initiation in conversion paralysis: an event-related potential study.

Conversion paralysis (CP) is featured by a stress-induced tonic immobility. Although the neural correlates of this psychiatric condition remain largely unexplored, previous reports showed CP to be associated with anterior cingulate cortex (ACC) hyperactivity. We examined the ACC action monitoring function by recording event-related potentials (ERPs) when conversion patients (n = 6) with unilateral arm paresis made speeded responses with their affected and healthy arms on a flankers task. During this task, pre-response ACC action monitoring is reflected in the N2 ERP component, which is increased when incongruent stimuli lead to simultaneously activated competing response tendencies. The results showed that the N2 congruency effects were significantly increased for responses with affected hands compared to healthy hands. There were no such results for post-response monitoring. This study is the first to present electrophysiological correlates of action monitoring in CP and suggests ACC to be hyperactive when movements with affected arms are to be initiated.

Adolescent↗

PubMed2005

The effects of stress-induced cortisol responses on approach-avoidance behavior.

High glucocorticoid stress-responses are associated with prolonged freezing reactions and decreased active approach and avoidance behavior in animals. The present study was designed to investigate the effects of cortisol responses and trait avoidance on approach-avoidance behavior in humans. Twenty individuals were administered a computerized approach-avoidance (AA)-task before and after stress-induction (Trier Social Stress Test). The AA-task involved a reaction time (RT) task, in which participants made affect congruent and affect incongruent arm movements towards positive and threatening social stimuli. Affect congruent responses involved arm extension (avoidance) in response to angry faces and arm flexion (approach) in response to happy faces. Reversed responses were made in affect incongruent instruction conditions. As expected, participants with high cortisol responses showed significantly decreased RT congruency-effects in a context of social stress. Low trait avoidance was also associated with diminished congruency-effects during stress. However, the latter effect disappeared after controlling for the effects of cortisol. In sum, in agreement with animal research, these data suggest that high cortisol responses are associated with a decrease in active approach-avoidance behavior during stress. These findings may have important implications for the study of freezing and avoidance reactions in patients with anxiety disorders, such as social phobia and post-traumatic stress disorder.

Adult↗

PubMed2005

Cortisol-induced impairments of working memory require acute sympathetic activation.

The present study assessed whether the effects of cortisol on working memory depend on the level of adrenergic activity (as measured by sympathetic activation) during memory performance. After exposure to a psychosocial stress task, participants were divided into cortisol responders and nonresponders. Cortisol responders showed working memory impairments during the psychosocial stress phase, when cortisol and adrenergic activity were enhanced, whereas nonresponders did not. During recovery, however, when cortisol levels were elevated but adrenergic activity was normalized, working memory of responders did not differ from that of nonresponders. Among several stress measures, cortisol was the only significant predictor for working memory performance during stress. These findings suggest that adrenergic activation is essential for the impairing effects of stress-induced cortisol on working memory.

Adolescent↗

PubMed2005

The impact of early trauma and recent life-events on symptom severity in patients with conversion disorder.

Although the presence of psychological stress factors in the evolution of conversion symptoms forms an important criterion for the DSM-IV diagnosis of conversion disorder, little is known about the nature and timing of these stress factors. Fifty-four patients with conversion disorder and 50 control patients with an affective disorder were screened for life events experienced in the year before the symptom onset. Conversion patients did not differ from control patients in the number or severity of life events, but showed a significant relation between the recent life events and the severity of conversion symptoms. Especially life events with respect to work and relationships contributed to this effect. These results remained when controlling for the previously found effects of childhood traumatization on the severity of conversion symptoms. The findings imply that conversion symptoms may be elicited by a complex of early and later negative life events and that traditional unifactorial trauma-theories of conversion disorder should be replaced by multifactorial stress models.

Adult↗

PubMed2004

Trauma and dissociation in conversion disorder and chronic pelvic pain.

OBJECTIVE: The purpose of this study was to: a) assess the link between sexual and/or physical abuse and dissociation in conversion disorder and chronic pelvic pain patients; and b) assess whether this effect is independent of level of general psychopathology. METHOD: This report examines data from four separate samples. Fifty-two patients with chronic pelvic pain, 61 patients with non-epileptic seizures, and two samples of patients (102 and 54) with predominantly motor or sensory types of conversion disorder were studied. RESULTS: Using point-biserial correlations no compelling evidence for a consistent and positive association of sexual and/or physical abuse with dissociation was found. After statistically controlling for level of psychopathology using multiple regression analyses, in most of the cases the association of abuse with dissociation was no longer statistically significant. Only physical abuse predicted level of somatoform dissociation over and above level of psychopathology. CONCLUSION: In future clinical studies of dissociation in patients with conversion disorder and chronic pelvic pain more complex models may be needed with less exclusive reliance on historical antecedents such as childhood abuse and more emphasis on recent potentially traumatizing experiences or co-morbid psychiatric disorders.

Adult↗

PubMed2002

Motor initiation and execution in patients with conversion paralysis.

Motor initiation and motor execution in four patients with conversion paralysis were investigated in a non-affected motor modality (speech). In line with the hypothesis of dissociated control in conversion disorder [Cognit. Neuropsychiatry 8 (1) (2001) 21] motor initiation, but not response duration, was expected to be impaired. The motor initiation times (reaction time: RT) and motor execution times (response duration: RD) were compared on four RT-tasks that required the production of a verbal response: a simple choice RT-task, a mental letter rotation task, and an implicit and an explicit mental hand rotation task. Because conversion disorder is expected to primarily involve an impairment in the initiation of movement, we expected the following task characteristics to uniquely affect RT and not RD: type of instruction (implicit versus explicit instructed imagery), angle of rotation, and target arm (affected versus non-affected arm). The results indeed showed the task characteristics to significantly affect the participants' RT and not their RD. It was concluded that conversion paralysis is associated with a specific impairment in the explicit initiation of processes with a spatial and motor component.

Adult↗

PubMed2002

Changes in PTSD patients' narratives during prolonged exposure therapy: a replication and extension.

Following E. B. Foa, C. Molnar, and L. Cashman (1995), narrative changes from the first to the last exposure session were compared for improved and nonimproved PTSD patients on fragmentation, organization, internal, and external events. Improved (n = 8) and nonimproved (n = 12) patients did not differ regarding changes in fragmentation or organized thoughts. However, improved patients showed a greater decrease in disorganized thoughts during treatment. Furthermore, all patients, independent of improvement, showed significant changes in the same direction; a decrease in disorganized thoughts and external events and an increase in internal events. Although previous results were partly replicated, it is concluded that narrative changes may be due to exposure treatment itself rather than to changes in memory representation.

Chronic Disease↗

PubMed2002

Hypnotic susceptibility in patients with conversion disorder.

Conversion disorder has been associated with hypnotic susceptibility for over a century and is currently still believed to be a form of autohypnosis. There is, however, little empirical evidence for the relation between hypnotic susceptibility and conversion symptoms. The authors compared 50 patients with conversion disorder with 50 matched control patients with an affective disorder on measures of hypnotic susceptibility, cognitive dissociation, and somatoform dissociation. Conversion patients were significantly more responsive to hypnotic suggestions than control patients. In addition, conversion patients showed a significant correlation between hypnotic susceptibility and the number of conversion complaints. These results provide the first evidence of a relationship between hypnotic susceptibility and the presence and number of conversion symptoms.

Adult↗

PubMed2002

Motor imagery during hypnotic arm paralysis in high and low hypnotizable subjects.

Previous research suggests that conversion disordered patients with hand/arm paralysis exhibit slowed reaction times for mental hand-rotation tasks that correspond to their affected arm when the tasks are explicitly instructed and not when they are implicitly cued. Because of the many similarities between hypnotic phenomena and conversion symptoms, the authors tested whether similar motor imagery impairment would occur among normal high hypnotizable subjects when paralysis is suggested. Nine high and 8 low hypnotizable subjects were administered an implicit and an explicit mental hand-rotation task during hypnotically suggested paralysis of the right arm. On the implicit task, there were no significant reaction time (RT) differences between highs and lows. On the explicit task, only highs showed a significantly larger RT increase per degree of rotation with the paralyzed arm, compared to the normal arm. These preliminary findings suggest that the motor imagery impairment observed in conversion paralysis can be induced in highs using hypnosis.

Adult↗

PubMed2002

Childhood abuse in patients with conversion disorder.

OBJECTIVE: Despite the fact that the assumption of a relationship between conversion disorder and childhood traumatization has a long history, there is little empirical evidence to support this premise. The present study examined this relation and investigated whether hypnotic susceptibility mediates the relation between trauma and conversion symptoms, as suggested by Janet's autohypnosis theory of conversion disorder. METHOD: A total of 54 patients with conversion disorder and 50 matched comparison patients with an affective disorder were administered the Structured Trauma Interview as well as measures of cognitive (Dissociative Experiences Scale) and somatoform (20-item Somatoform Dissociation Questionnaire) dissociative experiences. RESULTS: Patients with conversion disorder reported a higher incidence of physical/sexual abuse, a larger number of different types of physical abuse, sexual abuse of longer duration, and incestuous experiences more often than comparison patients. In addition, within the group of patients with conversion disorder, parental dysfunction by the mother-not the father-was associated with higher scores on the Dissociative Experiences Scale and the Somatoform Dissociation Questionnaire. Physical abuse was associated with a larger number of conversion symptoms (Structured Clinical Interview for DSM-IV Axis I Disorders). Hypnotic susceptibility proved to partially mediate the relation between physical abuse and conversion symptoms. CONCLUSIONS: The present results provide evidence of a relationship between childhood traumatization and conversion disorder.

Adult↗