PubMed Health⌕ Search

Biomedical subjects

P Eelen

Publications and source records attributed to P Eelen.

At least 19 recordsLinked to original sources
PubMed2005

Conservative bladder management in advanced multiple sclerosis.

Anticholinergics and intermittent catheterization are the cornerstones of bladder management in early multiple sclerosis (MS). In advanced MS however, bladder management is based more on tradition than on evidence. Nurses seem to deal with catheter problems and chronic incontinence. Despite the abundant use of indwelling catheters, there is a lack for guidelines on catheter-induced problems. The psychosexual and social impact of bladder problems in advanced MS is often neglected. The international multidisciplinary special interest group on sexual, urological and bowel dysfunction in MS (SUBDIMS) as a special interest group of the Rehabilitation in Multiple Sclerosis (RIMS) was confronted with a high variability in practice and a lack of guidelines. A literature review was prepared during three multidisciplinary expert meetings. This review will be the basis of further initiatives to improve the urological treatment of patients with advanced MS.

Evidence-Based Medicine↗
PubMed2001

Acquiring symptoms in response to odors: a learning perspective on multiple chemical sensitivity.

In this chapter, a learning account is discussed as a potential explanation for the symptoms in multiple chemical sensitivity. Clinical evidence is scarce and anecdotal. A laboratory model provides more convincing results. After a few breathing trials containing CO2-enriched air as an unconditioned stimulus in a compound with harmless odor substances as conditioned stimuli, subjective symptoms are elicited and respiratory behavior is altered by the odors only. Also, mental images can become conditioned stimuli to trigger subjective symptoms. The learning effects cannot be explained by a response bias or by conditioned arousal, and they appear to involve basic associative processes that do not overlap with aware cognition of the relationship between the odors and the CO2 inhalation. Learned symptoms generalize to new odors and they can be eliminated in a Pavlovian extinction procedure. In accordance with clinical findings, neurotic subjects and psychiatric cases are more vulnerable to learning subjective symptoms in response to odors. Consistent with a learning account, cognitive-behavioral treatment techniques appear to produce beneficial results in clinical cases. Several criticisms and unresolved questions regarding the potential role of learning mechanisms are discussed.

Administration, Inhalation↗
PubMed2001

Sequential and simultaneous feature positive discriminations: occasion setting and configural learning in human Pavlovian conditioning.

Using a conditioned suppression preparation, the authors investigated sequential (X --> A+/A-) versus simultaneous (XA+/A-) feature positive (FP) discrimination learning in humans. The sequential discrimination was expected to be resolved by means of a Feature X Modulated Target A-US association and the simultaneous discrimination by a feature X-US association. After sequential FP training, extinction of Feature X did not affect discriminative X --> A/A responding (Experiment 1), and X transferred its modulatory ability only to new targets, B, that had also been modulated (Experiment 2). This suggests that the sequential FP discrimination indeed resulted in occasion setting. Unlike expected, Feature X Extinction did not affect discriminative XA/A responding after simultaneous FP training (Experiment 3), while at the same time Feature X did show the predicted nonselective transfer to new targets, B (Experiment 4). J. M. Pearce's (1987) configural learning theory can account for most but not all findings of Experiments 3 and 4.

Adolescent↗
PubMed2000

Evaluative conditioning in the picture-picture paradigm with random assignment of conditioned stimuli to unconditioned stimuli.

Human participants were allocated to 1 of 3 groups. In the conditioning group, each conditioned stimulus (CS)-unconditioned stimulus (US) pair was presented 7 times during the acquisition phase. Participants who were assigned to the extinction group saw 5 additional presentations of each CS in isolation after the 7 presentations of each CS-US pair. In the latent inhibition group, the CS-only trials were presented before the CS-US trials. Overall, a significant evaluative conditioning effect was observed. This effect cannot be dismissed on the basis of the arguments developed by A. P. Field and G. C. L. Davey (1997, 1998, 1999), and the results thus provide strong evidence for the associative nature of evaluative conditioning. The results are also in line with other findings, which showed that evaluative conditioning is resistant to extinction.

Conditioning, Classical↗
PubMed2000

Pre-extinction of sensory preconditioned electrodermal activity.

In the present study, sensory preconditioning of human electrodermal activity was demonstrated. In the first phase of the experiment, two pairs of neutral pictures of human faces were presented (A/B and C/D) sequentially. In the second phase, one picture of one pair was immediately followed by an electrocutaneous stimulus (B+), and one picture of the other pair was not (D-). In the third phase the other picture of each pair (A and C) was tested. The effect of A and C alone presentations (pre-extinction) between the first and the second phase was investigated. When only those participants that showed reliable B+/D- differentiation were considered, the extinction group did not show stronger conditioned electrodermal activity to A than to C, whereas the control group did. These findings suggest that sensory preconditioning of anticipatory/preparatory responding only occurs when the pre-conditioned stimulus (A) actually predicts the conditioned stimulus (B).

Adult↗
PubMed1999

Acquisition and extinction of somatic symptoms in response to odours: a Pavlovian paradigm relevant to multiple chemical sensitivity.

OBJECTIVES: Multiple chemical sensitivity is a poorly understood syndrome in which various symptoms are triggered by chemically unrelated, but often odorous substances, at doses below those known to be harmful. This study focuses on the process of pavlovian acquisition and extinction of somatic symptoms triggered by odours. METHODS: Diluted ammonia and butyric acid were odorous conditioned stimuli (CS). The unconditioned stimulus (US) was 7.4% CO2 enriched air. One odour (CS+) was presented together with the US for 2 minutes (CS+ trial), and the other odour (CS-) was presented with air (CS-trial). Three CS+ and three CS-exposures were run in a semi-randomised order; this as the acquisition (conditioning) phase. To test the effect of the conditioning, each subject then had one CS+ only--that is, CS+ without CO2--and one CS- test exposure. Next, half the subjects (n = 32) received five additional CS+ only exposures (extinction group), while the other half received five exposures to breathing air (wait group). Finally, all subjects got one CS+ only test exposure to test the effect of the extinction. Ventilatory responses were measured during and somatic symptoms after each exposure. RESULTS: More symptoms were reported upon exposure to CS+ only than to CS-odours, regardless of the odour type. Altered respiratory rate was only found when ammonia was CS+. Five extinction trials were sufficient to reduce the level of acquired symptoms. CONCLUSION: Subjects can acquire somatic symptoms and altered respiratory behaviour in response to harmless, but odorous chemical substances, if these odours have been associated with a physiological challenge that originally had caused these symptoms. The conditioned symptoms can subsequently be reduced in an extinction procedure. The study further supports the plausibility of a pavlovian conditioning hypothesis to explain the pathogenesis of MCS.

Adult↗
PubMed1998

Attentional disruption is enhanced by the threat of pain.

Using a primary task paradigm this study investigated whether attentional disruption to a low-intensity electrocutaneous pain stimulus is enhanced by the threat of intense pain. Healthy volunteers (n = 38) performed a tone discrimination task in the presence of two types of distractors (a low-intensity electrocutaneous stimulus and a control stimulus) which they were instructed to ignore. In some trials, tone probes were presented immediately (250 ms) after distractor onset, further on (750 ms) during the distractor, and immediately (250 ms) after distractor offset. In a threat condition half of the participants were informed that a high-intensity painful stimulus would occur. As predicted, those participants who received the threat instructions, displayed a specific larger disruption of task performance immediately after the onset of the low-intensity pain stimulus in comparison with the control group.

Adolescent↗
PubMed1998

When somatic information threatens, catastrophic thinking enhances attentional interference.

Styles of catastrophic thinking about pain have been related to an inability to divert attention away from pain. We investigated whether pain catastrophizers displayed high attentional interference during a threatening low-intensity electrocutaneous stimulus (ES). In Experiment 1, 44 undergraduates performed a tone discrimination task whilst experiencing several times an ES on the left or right arms. Tones were also presented 250 ms and 750 ms after ES onset. Participants were threatened that a high-intensity painful stimulus would occur at one site. As predicted, pain catastrophizers displayed pronounced task interference immediately after threat stimulus onset. In Experiment 2, threat was induced in 36 undergraduates by informing them that an ES excites pain fibres. Again, catastrophizers had marked interference immediately after onset. The results are discussed in terms of how catastrophizing amplifies somatosensory information and primes fear mechanisms.

Adolescent↗
PubMed1998

Implicit and explicit memory for shape, body weight, and food-related words in patients with anorexia nervosa and nondieting controls.

Twelve patients with anorexia nervosa and 12 control participants watched a series of 64 words. There were 4 word types: anorexia related, positive, negative, and neutral. The last 3 types were anorexia unrelated. Anorexia-related words had the same affective valence as the neutral control words. Next, the participants completed an explicit memory test (cued recall) and an implicit memory test (word stem completion). Results showed a strong explicit memory bias for anorexia-related words for patients with anorexia nervosa but not for nondieting controls. There was no evidence for a similar bias in implicit memory. Results are discussed in the context of cognitive biases in psychopathology.

Adolescent↗
PubMed1998

Avoidance and confrontation of painful, back-straining movements in chronic back pain patients.

Avoidance of painful activities has been proposed to be an important risk factor for the initiation and maintenance of chronic low back suffering, whereas exposure to these activities has been suggested to be beneficial for recovery. In a cross-sectional study, the differences between chronic patients with avoidant and confrontational styles were investigated using self-report measures and a behavioral test. Participants were first classified as avoiders or confronters. In comparison with confronters, avoiders reported greater frequency and duration of pain, higher fear of pain and injury, more disability in daily living, and more attention to back sensations. Finally, avoiders reported more fear of (re)injury during the behavioral test and had a worse performance than confronters. The results suggest a close link between the fear of pain/(re)injury on one hand and avoidance behavior and physical deconditioning on the other hand.

Activities of Daily Living↗
PubMed1998

Affective Simon effects using facial expressions as affective stimuli.

Two experiments are reported in which facial expressions were presented and participants were asked to respond with the word POSITIVE or NEGATIVE on the basis of a relevant feature of the facial stimuli while ignoring the valence of the expression. Results showed that reaction times were influenced by the match between the valence of the facial expression and the valence of the correct response when the identity of the presented person had to be determined in order to select the correct response, but not when the gender of the presented person was relevant. The present experiments illustrate the flexibility of the affective Simon paradigm and provide a further demonstration of the generalizability of the affective Simon effect.

Adult↗
PubMed1998

Affective priming using a color-naming task: a test of an affective-motivational account of affective priming effects.

The affective priming effect, i.e. shorter response latencies for affectively congruent as compared to affectively incongruent prime-target pairs, is now a well-documented phenomenon. Nevertheless, little is known about the specific processes that underlie the affective priming effect. Several mechanisms have been put forward by different authors, but these theoretical accounts only apply to specific types of tasks (e.g. evaluation lexical decisions) or are rather unparsimonious. Hermans, De Houwer, and Eelen (1996) recently proposed a model of the affective priming effect that is based on the idea of the activation of corresponding or conflicting affective-motivational action tendencies. According to this model, affectively incongruent prime-target pairs should not only lead to relatively longer response latencies on tasks that concern the target word itself (target-specific tasks, e.g. evaluation pronunciation), but also on tasks that are unrelated to the actual identity of the specific target word. This hypothesis was tested in a series of four experiments in which participants had to name the color in which the target word was printed. In spite of procedural variations, results showed that the congruence between the valence of prime and target did not influence the color-naming times. The present results therefore provide no direct support for the affective-motivational account of the affective priming effect. Suggestions for future research are provided.

Adult↗
PubMed1998

Extinction in fear conditioning: effects on startle modulation and evaluative self-reports.

A basic feature of human evaluative conditioning is that the reported acquired valence of a previously neutral conditioned stimulus (CS) that has been paired with a valenced unconditioned stimulus (US), is resistant to extinction. The present study investigated whether startle modulation, sometimes presented as an index of acquired valence, reflected this basic feature. In a differential fear conditioning paradigm (n = 38) with an electrocutaneous stimulus as the US, a strong extinction manipulation was conducted by removing the US-electrodes and by extended extinction trials. At the end of extinction, the results corroborated previous findings of evaluative conditioning in that the reported valence for CS+ was still more negative than for CS-, despite disappearance of the differential skin conductance responses. However, startle modulation did not show resistance-to-extinction. Results were discussed in terms of recent conceptualizations of extinction.

Adolescent↗
PubMed1997

Habituation and the interference of pain with task performance.

Pain interrupts, distracts and is difficult to disengage from. In this experiment the attentional interference during pain is studied with a primary task paradigm. We were interested in the strength of attentional interference with repeated presentations of pain. Healthy volunteers (n = 24) performed a tone discrimination task in the presence of two types of distractors (an electrical pain stimulus and a control stimulus) which they were instructed to ignore. On some trials, tone probes were presented immediately (250 ms) after distractor onset, further on (750 ms) during the distractor, and immediately (250 ms) after distractor offset. Habituation of the task interference during the early processing of both the pain and the control stimulus was observed. It was also found that the attentional interference during pain did not completely disappear with repeated presentations. Finally, results clearly showed a more prolonged processing time of the tones during pain trials than during control trials. These results are discussed in terms of cognitive theories of habituation.

Acoustic Stimulation↗
PubMed1997

Startle intensification during painful heat.

Applying affective-motivational theories of emotions to pain presupposes that the immediate emotional reaction to pain can be conceptualized as an action disposition or an urge to escape. According to these emotion theories, an aversive emotional state should potentiate low-level reflexes with a matching affective tone. In line with this view, this study investigated whether the startle reflex, measured as the EMG peak amplitude of the eyeblink to a white noise burst, was intensified during painful heat. Twenty-four healthy volunteers were exposed twice to four heat stimuli (43, 45, 47 and 49 degrees C; 5 s duration). As predicted, an intensification of the startle reflex to the noise burst was observed during the high-intensity stimuli (47 and 49 degrees C) in comparison with the low-intensity stimuli (43 and 45 degrees C). The startle modulation was effective within a limited temporal window. Five seconds after heat offset, the startle intensification had disappeared.

Journal Article↗
PubMed1995

Respiratory learning and somatic complaints: a conditioning approach using CO2-enriched air inhalation.

In a differential respiratory conditioning paradigm with normal Ss two odors (fresh smelling niaouli and bad smelling ammonia) were used as conditioned stimuli (CS+ or CS-) and 7.4% CO2-enriched air was used as the unconditioned stimulus (US). Three CS+ and three CS- trials were run during acquisition, followed on the next day by the same number of CS+ and CS- only trials. Respiratory frequency, minute ventilation, end-tidal fractional concentration of CO2 and subjective complaints were measured throughout the experiment. While during acquisition all measures were affected, the conditioning effects included only respiratory frequency and subjective complaints. A selective association effect appeared in that the conditioning effects were confined to ammonia as CS+: respiratory frequency increased and more somatic complaints were presented when compared to the CS- condition. The conditioning effect on complaints was not confined to complaints of general arousal, but included respiratory complaints as well. Correlational analyses showed that increases in complaints as caused by the conditioning procedure were predicted by changes in somatic variables, but not by individual differences in Negative Affectivity.

Adolescent↗
PubMed1994

Sensory and temporal information about impending pain: the influence of predictability on pain.

Theories disagree about whether a verbal warning for pain has a detrimental or beneficial effect on the impact of an actual pain stimulus. Scheme-based theories predict a detrimental effect, whereas more representation-based, stimulus-comparator theories propose a beneficial effect. In this study, the influence of sensory predictability and temporal predictability is investigated. To control for attentional processes and to obtain a behavioral measure of the intrusive character of pain, an auditory discrimination task was introduced. This study firmly demonstrates that information about the painful nature of a heat stimulus does not a priori have detrimental effects on the impact of the stimulus. In fact, conditions in which a pain warning was given displayed a diminished impact in the SCR amplitude as well as in the subjectively reported intensity of the heat stimulus. Informing Ss about the exact time of administration did not add to the impact modulation, but instead resulted in a less-anxious state between signals. Although an overall behavioral disruption, particularly at onset, was observed, the behavioral data did not parallel the results of the two other response systems. Results are discussed in terms of scheme-based models, stimulus-comparator theories and the safety-signal hypothesis.

Adolescent↗