Edwin Verstraeten - Academia.edu (original) (raw)

Papers by Edwin Verstraeten

Sleep, Jun 15, 2004

As the effects of general slowness and decreased attentional capacity on higher executive attenti... more As the effects of general slowness and decreased attentional capacity on higher executive attention have not been fully taken into account in the sleep apnea literature, we statistically controlled for basic attentional performance in evaluating executive attention per se in sleep apnea patients. A case-controlled design was used with comparison of basic and executive attentional tasks. Thirty-six polysomnographically diagnosed patients (mean apnea-hypopnea index = 60.5 +/- SD 31.6) participated, together with 32 healthy controls. Neuropsychological tests included Trail Making part A and B, Symbol Digit Modalities (SDMT), Digit Span forward and backward, Stroop Color-Word, Five-Point design fluency, and an Attentional Flexibility task. Patients' vigilance data indicated time-on-task decrements after 10 minutes. Moreover, their performance was significantly reduced on the SDMT (effect size d = 0.93), the Digit Span forward task (d = 0.44), the number of errors on the basic 2-choi...

Can event-related electro-encephalogram (EEG) responses provide support for the occurrence of spo... more Can event-related electro-encephalogram (EEG) responses provide support for the occurrence of spontaneous trait inferences (STI)? Participants read sentences describing the behavior of a target person from which a strong trait could be inferred. The last word of each sentence determined the consistency with the trait induced during an introductory paragraph. In comparison with sentences that were consistent with the implied trait, when the sentences were inconsistent, an event-related P300 waveform was observed at parietal scalp regions (Pz). This dependency on behavioral consistency indicates that trait inferences were made spontaneously. Memory measures taken after the presentation of the stimulus material involved sentence completion and trait-cued recall, and also supported the occurrence of spontaneously inferred traits associated with the actor. Interestingly, increased memory for consistent relative to inconsistent behaviors at the trait-cued recall task was significantly correlated with the P300, which supports this latter measure as a valid neural correlate of spontaneous trait inferences.

Sleep, 2004

Study objectives: As the effects of general slowness and decreased attentional capacity on higher... more Study objectives: As the effects of general slowness and decreased attentional capacity on higher executive attention have not been fully taken into account in the sleep apnea literature, we statistically controlled for basic attentional performance in evaluating executive attention per se in sleep apnea patients. Design: A case-controlled design was used with comparison of basic and executive attentional tasks. Participants: Thirty-six polysomnographically diagnosed patients (mean apnea-hypopnea index = 60.5 ± SD 31.6) participated, together with 32 healthy controls.

Otology & Neurotology, 2005

Objective: Tinnitus is a distressing symptom for which few treatments exist. It leads to an impor... more Objective: Tinnitus is a distressing symptom for which few treatments exist. It leads to an important decrease in quality of life in 2 to 3% of the population. Tinnitus is considered a phantom sound, the result of cortical reorganization. Transcranial magnetic stimulation (TMS) is a noninvasive method to modulate cortical reorganization and has been shown to be able to influence tinnitus perception. Study Design: Retrospective analysis. Setting: Tertiary referral center. Patients: The effect of TMS of the contralateral auditory cortex in 114 patients with unilateral tinnitus is investigated as one of the selection criteria used for surgical implantation of electrodes on the auditory cortex. Intervention: TMS is performed at 90% of motor threshold at 1, 3, 5, 10, and 20 Hz, with each stimulation session consisting of 200 pulses. Results were classified as no effect (0-19% improvement), partial effect (20-79% improvement), and good effect (80-100 suppression).

Social Cognitive and Affective Neuroscience, 2007

This study measured event-related potentials during spontaneous and intentional trait inferences.... more This study measured event-related potentials during spontaneous and intentional trait inferences. Participants read sentences describing the behavior of a target person from which a strong moral trait could be inferred. The last word of each sentence determined the consistency with the trait induced during an introductory paragraph. In comparison with behaviors that were consistent with the implied trait, a P300 waveform was obtained when the behaviors were evaluative inconsistent with that trait. This dependency on behavioral consistency indicates that trait inferences were made previously while reading the preceding behaviors, irrespective of the participants' spontaneous or intentional goals. Overall, the P300 shows considerable parallels between spontaneous and intentional inferences, indicating that the type and timing of the inconsistency process is very similar. In contrast, source localization (LORETA) of the event-related potentials suggest that spontaneous inferences show greater activation in the temporo-parietal junction compared to intentional inferences following an inconsistency. Memory measures taken after the presentation of the stimulus material involved sentence completion and trait-cued recall, and supported the occurrence of trait inferences associated with the actor. They also showed significant correlations with the neural components (i.e. P300 and its current density at the temporo-parietal junction) predominantly following spontaneous instructions, indicating that these components are valid neural indices of spontaneous inferences.

Sleep Medicine Reviews, 2004

Sleep apnea patients' nocturnal breathing disturbances cause daytime sleepiness and cognitive imp... more Sleep apnea patients' nocturnal breathing disturbances cause daytime sleepiness and cognitive impairments. Attentional capacity and vigilance deficits have often been observed. Moreover, some studies have suggested executive dysfunction, usually assumed to be related to (pre)frontal lobe dysfunction caused by intermittent hypoxemia. However, sleep disruption itself has a pervasive influence on cognitive function and affects not only underlying 'lower-level' processes such as arousal and alertness, but also 'higher-level' cognitive processes such as executive attention. This methodological caveat has not been fully taken into account in the sleep apnea literature. In order to be able to disentangle these cognitive processes on different levels, sound theoretical neurocognitive frameworks are needed to attain careful analyses and interpretations of neuropsychological data. Therefore, this paper firstly presents an overview of relevant theoretical concepts and models of arousal, attention, and executive function. Then, it is being argued that these theoretical considerations have important methodological implications. These methodological concerns are being addressed by specific experimental and statistical approaches, illustrated by some well-known neuropsychological tests. It can be concluded that the reported executive deficits in sleep apnea patients should be regarded as tentative, and that more case-controlled studies are needed using fine-grained analyses to parcel complex cognitive abilities into their subcomponents. q

Sleep Medicine Reviews, 2006

Insomnia has usually been studied from a behavioral perspective. Somatic and/or cognitive conditi... more Insomnia has usually been studied from a behavioral perspective. Somatic and/or cognitive conditioned arousal was shown to play a central role in sleep complaints becoming chronic, and was used as a starting point for the development of treatment modalities. The introduction of the neurocognitive perspective, with its focus on cortical or CNS arousal, has given rise to a renewed interest in the neurophysiological characteristics of insomnia. Recent research, using quantitative EEG, neuroimaging techniques and the study of the microstructure of sleep, suggests a state of hyperarousal with a biological basis. Furthermore, insomnia might not be restricted to sleep complaints alone because it appears to be a 24-h disorder, affecting several aspects of daytime functioning as well. These new findings have implications for the treatments used and indicate that a focus on cortical or CNS arousal should be pursued. As such, the use of EEG neurofeedback, a self-regulation method based on the paradigm of operant conditioning, might be a promising treatment modality. Preliminary results for insomnia and successful applications for other disorders suggest that this treatment can have the necessary stabilizing effects on the EEG activity, possibly resulting in a normalizing effect on daytime as well as nighttime functioning. Q

Current Neurology and Neuroscience Reports, 2007

The nature of the neurocognitive deficits found in obstructive sleep apnea is still debatable. Wh... more The nature of the neurocognitive deficits found in obstructive sleep apnea is still debatable. What is the extent of higher executive versus alertness-based cognitive dysfunction? Are cognitive impairments caused by nighttime hypoxemia or daytime sleepiness? This paper demonstrates the importance of a sound theoretical neurocognitive framework to be able to answer these questions. A strategy to assess executive function is proposed and illustrated with well-known neuropsychological tests. It seems that the pervasive effects of decreased alertness on higher cognitive functioning were not fully taken into account in those studies in which executive dysfunction has been found and has been related to prefrontal lobe damage caused by intermittent hypoxemia. Therefore, a basal slowing in information processing, primarily due to sleepiness, may explain most of the neurocognitive deficits in sleep apnea. This conjecture appears to be in agreement with recent functional MRI studies indicating sleep loss as the primary cause of neurocognitive deficits, more so than hypoxemia.

Orl-journal for Oto-rhino-laryngology and Its Related Specialties, 2006

Biological Psychology, 2008

A robust physiological finding is a higher relative left sided activity in the prefrontal cortex ... more A robust physiological finding is a higher relative left sided activity in the prefrontal cortex during the experience of positive approach related emotions and a higher relative right sided activity during the experience of negative withdrawal related emotions. Since self-esteem can be conceptualized within a framework of approach/withdrawal tendencies, the present study aimed at investigating if the relation between frontal EEG alpha asymmetry and depressive symptoms is mediated by implicit or explicit self-esteem. Self-esteem was measured by questionnaires (explicit) and in an indirect way (implicit). The mediation analyses showed that only explicit self-esteem acted as a partial mediator in the path from EEG alpha asymmetry to depression. #