Wolfgang Dillo

Impaired top-down processes in schizophrenia: A DCM study of ERPs

Perception is not simply based on a hierarchical organization of the brain; it arises from an interplay between inputs from the environment and internal predictions of these inputs. It is an active process which involves an interaction between bottom-up information coming from the senses and feedback connections coming from higher-order cortical areas. In our experiment, we use the hollow-mask illusion to investigate the strength of top-down processes in schizophrenic patients and healthy controls. By using dynamic causal modelling (DCM) on functional magnetic resonance tomography (fMRI) data, we have presented evidence to suggest that patients with schizophrenia are less constrained by top-down processes during perception (Dima, D., Roiser, J.P., Dietrich, D.E., Bonnemann, C., Lanfermann, H., Emrich, H.M., Dillo, W., 2009. Understanding why patients with schizophrenia do not perceive the hollow-mask illusion using dynamic causal modeling. Neuroimage 46, 1180-1186). In this study, we re-address this issue by using DCM on event-related potentials (ERPs) data. Our aim was to validate our previous findings by conducting the same connectivity analysis--DCM--on data obtained from a different neuroimaging method. Our results confirm our initial hypothesis that top-down influences are constrained in schizophrenia, especially in perceptual tasks that require top-down control, like the hollow-mask illusion.

Neuronal correlates of ADHD in adults with evidence for compensation strategies--a functional MRI study with a Go/No-Go paradigm

Objective: Response inhibition impairment is one of the most characteristic symptoms of attention-deficit/hyperactivity disorder (ADHD). Thus functional magnetic resonance imaging (fMRI) during a Go/No-Go task seems to be an ideal tool for examining neuronal correlates of inhibitory control deficits in ADHD. Prior studies have shown frontostriatal abnormalities in children and adolescents. The aim of our study was to investigate whether adults with ADHD would still show abnormal brain activation in prefrontal brain regions during motor response inhibition tasks. Methods: fMRI was used to compare brain activation in 15 untreated adult patients with ADHD and 15 healthy reference volunteers during performance of a Go/No-Go task. Results: In contrast to various other studies with children and adolescents with ADHD, we found no significant difference in the activity of anterior cingulate cortex (ACC) or other frontostriatal structures between ADHD and healthy adults. Significantly enhanced activity was found in the parietal cortex, which is known to play an important role in building up attention. Conclusion: We hypothesize that the enhanced activity is due to the ability of adult ADHD patients to compensate their deficits for a short time, which is demonstrated in our study by equal task performance in both groups.

Computertomographische Untersuchungstechnik und Anatomie des Felsenbeins

ZusammenfassungStandarduntersuchung des Felsenbeins unter besonderer Berücksichtigung der Innenohrstrukturen ist die hochauflösende Spiral-Computertomographie (-CT) mit niedriger Dosis. Im Vergleich von Standard- und Spiraltechnik zeigt sich lediglich ein minimaler Qualitätsverlust. Die knöchernen Begrenzungen der Kochlea kommen mit der Standardtechnik geringgradig schärfer zur Darstellung, wodurch die diagnostische Aussagekraft der Spiraltechnik jedoch nicht beeinflußt wird. Bei regelrechtem Befund ermöglichen die originalen Schichtbilder mit hinreichender Sicherheit eine Beurteilung der Strukturen. In Zweifelsfällen oder bei ungünstig angeschnittenen Strukturen ist es jedoch nicht immer möglich, exakt zwischen pathologischem und regelrechtem Befund zu differenzieren. Mittels der optimierten Sekundärreformationen aus dem Spiraldatensatz lassen sich alle Strukturen in ihrem Verlauf darstellen und optimal beurteilen.AbstractLow-dose spiral-CT has gained standard in the preoperative examination of cochlea-implant patients. There is only a minimal loss of quality from spiral-CT when compared with standard-CT, which is not relevant for the diagnosis. In cases when all structures seem to be regular, the axial sections are sufficient for the diagnosis. In cases of doubt or complex pathology two-dimensional reformations are an important tool for the diagnosis. Multiplanar reformats provide the presentation of all interesting structures in their whole extension and thus enable an exact diagnosis.

CT-Pathologie des Felsenbeins

ZusammenfassungDie hochauflösende Computertomographie (CT) ist die Methode der Wahl für die bildgebende Diagnostik pathologischer Veränderungen des Felsenbeins, wenn sie den Knochen und die pneumatisierten Räume betreffen. In Form einer Übersichtsarbeit wird der heutige Stellenwert der CT bei Fehlbildungen, Traumen, Entzündungen, Tumoren und Knochendystrophien im Bereich des Felsenbeins dargestellt.AbstractHigh-resolution CT is the method of choice for diagnostic imaging in pathologic findings of the petrous bone, especially in all cases involving the bone and pneumatized spaces. This review article presents the actual value of CT in malformations, traumatic injuries, inflammations, tumors and bone dystrophies.

Word recognition memory in adults with attention-deficit/hyperactivity disorder as reflected by event-related potentials.

Objective: Attention-deficit/hyperactivity disorder (ADHD) is increasingly diagnosed in adults. In this study we address the question whether there are impairments in recognition memory. Methods: In the present study 13 adults diagnosed with ADHD according to DSM-IV and 13 healthy controls were examined with respect to event-related potentials (ERPs) in a visual continuous word recognition paradigm to gain information about recognition memory effects in these patients. Results: The amplitude of one attention-related ERP component, the N1, was significantly increased for the ADHD adults compared with the healthy controls in the occipital electrodes. The ERPs for the second presentation were significantly more positive than the ERPs for the first presentation. This effect did not significantly differ between groups. Conclusion: Neuronal activity related to an early attentional mechanism appears to be enhanced in ADHD patients. Concerning the early or the late part of the old/new effect ADHD patients show no difference which suggests that there are no differences with respect to recollection and familiarity-based recognition processes.

Quality of life in autism spectrum disorder

Abstract Background: It is well known that individuals with autism spectrum disorders (ASD) show impairments in areas such as social interaction and flexibility and often are without employment and partnership. But

Asperger syndrome and partnership

Abstract Background: Asperger Syndrome (AS) is a kind of an Autism Spectrum Disorder (ASD), which is characterized by patterns of repetitive behavior, special interests and difficulties in social interaction. Especially

In the eye of the beholder-rating of facial attractiveness in adult asperger syndrome

Abstract Background: Sense of facial attractiveness seems to be uniform within a particular culture and between different cultures in non-autistic persons. Individuals with an autism spectrum disorder have a different

Möglichkeiten und Grenzen der Spiral-CT in der neuroradiologischen Diagnostik

ZusammenfassungDie Spiral-CT-Technik bietet für die neuroradiologische Diagnostik neue Möglichkeiten. Die hohe Qualität der multiplanaren und 3D-Rekonstruktionen aus Spiral-CT-Datensätzen erhöht die Aussagekraft erheblich. Der Einsatz der Spiral-CT ist indiziert für die Untersuchung von knöchernem Schädel und Wirbelsäule sowie der Weichteile der Schädelbasis und des Halses. Mit der CT-Angiographie lassen sich mit kurzen Untersuchungszeiten (<1 Minute) nichtinvasiv mit einem intravenösen Kontrastmittelbolus, die großen Gefäße im Kopf-Hals-Bereich darstellen. Die Wertigkeit der CT-Angiographie wird jedoch häufig überschätzt. Bei kritischem Vergleich zeigt sich, daß die CT-Angiographie die etablierten Untersuchungsmethoden (DSA, Doppler-, Duplexsonographie) nur in Ausnahmefällen ersetzen kann. Es werden die Einsatzmöglichkeiten des Spiral-CT in der Neuroradiologie und deren Grenzen beschrieben.SummarySpiral-CT provides new diagnostic features in neuroradiologic imaging. The high quality of two- and threedimensional reconstructed images from spiral-CT data improves the diagnostic value. Spiral-CT is indicated for the examination of all bony structures of head and spine and soft tissue of skull base and neck. CT-angiography enables the presentation of large vessels of head and neck with less than 1 min of examination time. The value of CT-angiography however is often overestimated. The critical review shows, that only in few indications CT-angiography is able to replace established methods like DSA, Doppler- or duplexsonography. We describe the application of spiral-CT in neuroradiology and their limitations.