Zeitschrift für Medizinische Psychologie

Anxiey in patients undergoing computed tomography or magnetic resonance imaging

Objectives: A significant proportion of patients undergoing either computed tomography (CT) or magnetic resonance imaging (MRI) experience moderate to severe levels of anxiety which sometimes lead to the termination of the procedure.

Methods: We collected several measures of anxiety (observation, questionnaires, heart rate/blood pressure) in 51 CT-patients and 52 MRI-patients before and after the procedure.

Results: The level of anxiety was altogether low for all measures. The physiological measures showed elevated levels of anxiety before the examination which returned to normal levels after the examination. Only about 10% of the patients reported strong anxiety or panic during the examination. In regard to the triggers of anxiety, the patients; concerns about possible serious diagnostic findings were clearly more important than environmental factors, negative interactions with the medical staff or waiting for the examination. MRI-patients altogether experienced more anxiety than CT-patients, probably due to the more stressful environmental conditions (constriction, noise).

Conclusion: The approximately 10% of patients who experience strong anxiety or panic should be identified before an examination using a simple screening questionnaire.l They should then receive special treatment (e.g. additional information, tranquilizers).

Association of a polymorphism in the H6PD gene and basal cortisol secretion, body fat mass and leptin level

The hypothalamus-pituitary-adrenal (HPA) axix is vital for an organism's response to physical or psychosocial stimulation. Chronic dysregulation of HPA axis activity is related to several psychiatric and psychosomatic disorders. Cortisol, the end product of this endocrine system, affects a multitude of systems in the body, including the HPA axis itself and it also has an influence on behavior. The intracellular availability of cortisol is crucial for the regulation of this endocrine system. The enzyme hexose-6-phosphat-dehydrogenase (H6PDH) affects cortisol availability via its influenec on 11β-hydroxysteroid dehydrogenase type I (11β-HSDI)-activity, which regenerates cortisol from inactive cortisone. 116 healthy males (33 monozygotic & 25 dizygotic twin pairs) were studied to estimate the association between a polymorphism in the exon 5 of the H6PD gene (R435Q, GA) and adrenocortical responses to psychosocial stress, basal salivary cortisol levels and body composition. Compared with subjects with the more frequent H6PD genotypers the homozygous AA-carriers displayed a significantly decreased cortisol awakening rise (CAR) as well as lower daytime cortisol levels. In response to stress, the AA-carriers exhibited a trend towards lower cortisol and ACH responses compared with GG- and GA-carriers. In addition, significantly higher levels of leptin and amount of body fat were observed in AA-carriers. We hypothesize that the R453Q polymorphism in the H6PD gene might influence intracellular cortisol availability and thus affect HPA axis regulation.

Improvement of residual vision by visuo-spatial cueing in patients with homonymous visual field loss

Objectives: In areas of residual vision of patients with visual field defects, perceptual thresholds are elevated. Can visual performance of patients – like in healthy subjects – be improved by orienting attention at the visual field border with a spatial cue?

Methods: Experiment 1: Test of immediate, short-term effects of attention of a spatial cue in a visual field test. Experiment 2: Use of the same cue in a training program for the restoration of visual functions (experimental group) and comparison with the effects of visual field training without a cue (control group).

Results: Experiment 1: Compared to uncued conditions, stimulus detection was increased and reaction times were decreased after presentation of a cue. The size of the attention effect depended on the size of the area of residual vision. Experiment 2: The experimental group showed a more pronounced permanent increase of intact field size in the cued area than in unattended regions or than the control group. The cue changed the topographical pattern of visual field plasticity.

Conclusion: A systematic combination of light stimulation (bottom-up) at the visual field border with spatial attention (top-down) yields short-term as well as long-term improvement of visual function that is more pronounced than the effects of light stimulation alone. Cognitive processes established in research with healthy subjects can be implemented in neuropsychological rehabilitation to improve treatment outcome.

This paper reviews the use of event-related brain potentials (ERPs) in clinical neuropsychology research. First, a short overview of basic methodological issues is given. The main part reviews studies that explored the information processing stages that are reflected by the ERP-components. Here, the focus is on components that have been used in clinical neuropsychology research (early, attention-sensitive components; mismatch-negativity (MMN); P300; N400; lateralized readiness potential; CNV; readiness potential; error-related negativity). For each component, examples of research relevant for clinical neuropsychology are given

ERPs are a very powerful tool in exploring information processing deficits in patients with brain damage, and developmental or degenerative neurological conditions. Their main contribution is the revelation of the time-course of information processing and of the subprocesses involved in complex cognitive activities. Thus, ERPs can provide new insights into the time-course of information processing deficits in brain damaged patients.