TY  - JOUR
A1  - Strik, Werner K.
A1  - Dierks, Thomas
A1  - Franzek, Ernst
A1  - Stöber, Gerald
A1  - Maurer, Konrad
T1  - P 300 asymmetries in schizophrenia revisited with reference-independent methods
N2  - Evidence of hemispheric asymmetries in schizophrenia has been reported from different research areas. Asymmetries in evoked potential P300 topography are still controversial because of inconsistent findings. In the present study. previous results of abnormal lateralization of P300 were replicated in stabilized residual Schizophrenie patients. Auditory P300 was recorded during an odd ball task in which subjeets detected rare target stimuli. Schizophrenie patients had the P300 peak shifted to the right hemisphere and differed signifieantly from age- and sex-matched normal control subjects who had left-lateralized P300 peaks. A comparison of different methods of assessment and analysis of the topographical features of the P300 electric fields showed that the extraction of reference-independent descriptors of P300 topography is a reliable and sensitive method for statistical handling of the maps. The results suggest left hemispheric dysfunction during cognitive tasks in a subgroup of Schizophrenie patients. Inconsistencies between previous sturlies are likely to be due to heterogeneous patient groups, which may have included patients in an acute Schizophrenie episode or patients in clinical remission. lnvestigation of the clinical meaning of P300 alterations requires careful psychopathological definition of the patient groups.
KW  - Schizophrenie
KW  - Laterality
KW  - evoked potentials
KW  - electroeneephalography
Y1  - 1994
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63372
ER  - 
TY  - THES
A1  - Fackelmann, Stefanie
T1  - Langzeitkorrelation evozierter Potentialparameter mit dem klinischen Verlauf bei Patienten mit Multipler Sklerose
T1  - Early abnormalities of evoked potentials and future disability in patients with multiple sclerosis
N2  - Evozierte Potenziale werden bereits als Hilfsmittel zur Diagnosestellung der Multiplen Sklerose herangezogen. Das Spektrum der Verläufe der Erkrankung ist sehr unterschiedlich. Ziel der Studie war es, zu prüfen, ob visuell (VEP), somatosensibel (SEP) und Magnet- (MEP) evozierte Potentiale durch das Aufdecken klinisch noch stummer Läsionen eine prognostische Bedeutung haben. Es wurden 94 Patienten bei Erstvorstellung sowie zum 5-Jahres- und 10-Jahresverlaufszeitpunkt untersucht. Es wurde ein Zusammenhang von MEP- und SEP-Scores mit dem späteren Behinderungsgrad, gemessen in Form der EDSS nach fünf und zehn jahren gefunden, sofern die elektrophysiologischen Untersuchungen in den ersten beiden Jahren nach Erstmanifestation klinischer Symptome durchgeführt worden waren (Gruppe 1, 44 Patienten). Für Gruppe 2 (50 Patienten), deren Erstuntersuchung später im Verlauf stattgefunden hatte (im Mittel 9,6a) konnte keine prognostische Bedeutung gesehen werden. Die Durchführung multimodaler evozierter Potenziale ist kann somit eine Hilfestellung zur frühzeitigen Therapieentscheidung geben.
N2  - Evoked potentials (EP) have a role in making the diagnosis of multiple sclerosis (MS) but their implication for predicting the future disease course in MS is under debate. EP data of 94 MS patients examined at first presentation, and after five and ten years were retrospectively analysed. Patients were divided into two groups in relation to the prior duration of disease at the time point of first examination: group 1 patients (n-44) were first examined within two years after disease onset, and group 2 patients (n-50) at later time points. As primary measures sum scores were calculated for abnormalities of single and combined EP (visual (VEP), somatosensory (SEP), magnetic motor evoked potentials (MEP)). In patients examined early after disease onset (group 1), a significant predictive value for abnormal EP was found with MEP and SEP sum scores at first presentation correlating significantly with Expanded Disability Status Scale (EDSS) values after five years, while the VEP sum score was not. The cumulative number of abnormal MEP, SEP and VEP results also indicated higher degrees of disability (EDSS≥ 3.5) after five years. Combined pathological SEP and MEP findings at first presentation best predicted clinical disability (EDSS≥ 3.5) after five years (odds ratio 11.0). EP data and EDSS at first presentation were not significantly linked suggesting that EP abnormalities at least in part represented clinically silent lesions not mirrored by EDSS. For patients in later disease phases (group 2), no significant associations between EP data at first presentation and EDSS at five and ten years were detected. Together with clinical findings and MR imaging, combined EP data may help to identify patients at high risk of long-term clinical deterioration and guide decisions as to immunomodulatory treatment.
KW  - Multiple Sklerose
KW  - Evozierte Potenziale
KW  - multiple sclerosis
KW  - evoked potentials
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64840
ER  - 
TY  - THES
A1  - Vogel, Marc
T1  - Einfluss der Reizdarbietung auf die elektrophysiologischen Korrelate der motorischen Steuerung
T1  - Influence of stimulus presentation on the electrophysiological correlates of motor control
N2  - In dieser Arbeit wurden die motorische Steuerung und ihre vermuteten elektrophysiologischen Korrelate (N200, P300 und NGA) näher untersucht. Dazu wurden fünf verschiedene Paradigmen (Continuous Performance Tests, CPTs)an 23 gesunden Probanden durchgeführt und die ereigniskorrelierten Potentiale aufgezeichnet. Die CPTs unterschieden sich jeweils in der Art der Reizdarbietung (visuelle/akustische Modalität, Präsentationsdauer, Inter-Stimulus-Intervall). Die Ergebnisse dieser Studie deuten auf einen Zusammenhang der elektrophysiologischen Parameter mit der motorischen Steuerung hin. Die elektrophysiologischen Unterschiede zwischen der Ausführung (Go) und der Hemmung (NoGo) einer vorbereiteten motorischen Antwort sind stabil und zeigen, dass ihnen unterschiedliche Prozesse zugrunde liegen.
N2  - In this work, motor control and its presumed electrophysiological correlates (N200, P300 and NGA) were studied. For this purpose 23 healthy subjects performed five different paradigms (Continuous Performance Tests, CPTs) with registration of event-correlated potentials. The CPTs differed in the type of stimulus presentation (visual/acoustic modality, presentation time, inter-stimulus-interval). The results of this study indicate a correlation of the electrophysiological parameters with motor control. The electrophysiological differences between execution (Go) and inhibition (NoGo) of a prepared motor response are stable and show that there are different processes underlying the two conditions.
KW  - NGA
KW  - N200
KW  - P300
KW  - CPT
KW  - evozierte Potentiale
KW  - NGA
KW  - N200
KW  - P300
KW  - CPT
KW  - evoked potentials
Y1  - 2003
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-10401
ER  -