Biomedical subjects

Wilhelm Dengler

Publications and source records attributed to Wilhelm Dengler.

4 recordsLinked to original sources

PubMed2005

Electrocortical evidence for an early abnormal processing of panic-related words in panic disorder patients.

Panic patients are hypothesized to have particularly elaborated cortical networks for panic-related stimuli, and this characteristic should be associated with an abnormal automatic processing of these stimuli. Panic-related and neutral words were presented to 25 panic patients and 25 matched healthy controls either at individually determined perception thresholds (threshold condition) or for 1000 ms (above threshold condition). Word recognition for words presented at perception threshold (threshold words), and event-related brain potentials (ERPs) triggered by threshold and above threshold words were analyzed. In the threshold condition, both panic patients and control participants correctly recognized more panic-related than neutral words. An additional analysis restricted to participants who used an intuitive strategy for word identification revealed an enhanced frequency of correctly identified panic-related words in panic patients. In the ERPs, only panic patients exhibited enhanced positive potentials during early time windows (200-400 ms after stimulus presentation) triggered by panic-related compared to neutral threshold words. In late (400-600 ms) and very late (600-1000 ms) time windows, both groups showed a greater ERP positivity for panic-related than for neutral words. These data suggest that panic patients are characterized by an early automatic and elaborated processing of disorder-relevant stimuli.

Adult↗

PubMed2005

Selective processing of pain-related word stimuli in subclinical depression as indicated by event-related brain potentials.

An intense discussion still exists as to whether pain and depression are causally related or independent of each other. To investigate processing of pain-related word stimuli in subclinically depressed individuals, we designed an event-related potentials study in a group control design. Pain words and neutral words were presented to 16 subclinically depressed and 16 control participants. Behavioral and electrophysiological measures were taken during lexical decision and recognition tasks. Depressive compared to control participants showed enhanced P300 amplitudes at parietal electrodes triggered by pain-related words during the lexical decision task, which presumably is a sign of enhanced recollection processes for these word stimuli. In line with these electrophysiological findings, depressed participants also tended to better recall the pain-related words in the later recognition task than control participants. We conclude that subclinically depressed individuals selectively process pain-related stimuli, and this processing bias could enhance their vulnerability to develop pain symptoms.

Adult↗

PubMed2005

Covariation bias and its physiological correlates in panic disorder patients.

A covariation bias, i.e., the overestimation of random contingencies between fear-relevant stimuli and aversive consequences, seems to characterize anxiety disorders. Panic patients (n=30) and healthy controls (n=25) were exposed to panic-relevant, neutral, and phobia-relevant but panic-irrelevant picture stimuli, followed randomly be aversive consequences (acoustic startle stimuli). While covariation estimates reflected objective contingencies in both groups, only panic patients revealed a more negative Contingent Negative Variation (CNV) to panic-relevant than to phobia-relevant and neutral pictures. For startle reflex, only main effects of picture category were found, indicating that valence effects of picture stimuli were not specifically distorted in panic patients. CNV presumably reflects a biased processing of disorder-relevant stimuli by panic patients, perhaps with the expectation that aversive consequences will follow these stimuli.

Acoustic Stimulation↗

PubMed2005

Implicit and explicit memory processes in panic patients as reflected in behavioral and electrophysiological measures.

Implicit and explicit memory processes for panic-relevant and neutral word stimuli were examined in 16 panic patients and 16 healthy participants matched for sex, age, and education, using behavioral and electrophysiological measures. In the study phase, panic-relevant and neutral words were presented and the level of processing was varied by requiring either shallow (orthographic) or deeper (syntactic) processing. Implicit memory was tested with a lexical decision task, explicit memory with a recognition task. Panic patients and healthy participants did not differ in behavioral (response time) or event-related brain potential (ERP) measures of implicit memory. However, panic patients deviated from healthy participants in the recognition test, an explicit memory test. Although recognition of panic words was overall worse compared to neutral words, panic patients compared to healthy participants exhibited enhanced discrimination scores and faster reaction times for panic words. The level of processing manipulation had comparable effects on patients and healthy participants. While neither behavioral nor electrophysiological measures provided evidence for an implicit memory bias in panic patients, behavioral measures confirmed an explicit memory bias in panic patients for panic-relevant stimuli.

Adult↗