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Six patients with Parkinson's disease (PD) reporting unusually fast or sudden onset of sleep under the addition of dopamine agonists to a previous levodopa-containing therapy were examined using a sleep–wake diary, the Epworth sleepiness scale (ESS), polysomnography, multiple sleep latency tests (MSLT), a standardized vigilance test, and driving simulation. In all patients, ESS scores were increased and polysomnography showed disruption of the sleep pattern, a tendency towards poor sleep efficiency, and reduced proportions of slow- wave and rapid eye movement sleep. Pathological results in the MSLT or the vigilance test were obtained in five cases. For evaluation of driving performance, the standard deviation from the mean lane position during driving simulation was calculated. Three of five patients had clearly increased mean SDLP values. With respect to the measurement of daytime sleepiness (ESS, MSLT, vigilance test, and driving simulation), each patient had pathological results in at least two of these examinations. However, only a limited transfer of the routine vigilance assessment to driving performance was possible. In summary, this pilot study indicates that unusually fast or sudden onset of sleep in PD patients is a phenomenon of daytime sleepiness. © 2002 Movement Disorder Society.

Zusammenfassung: Übung bzw. Training reduziert im allgemeinen die Bearbeitungszeit zur Lösung eines Problems. Diese Zeiteinsparung wird oft auf eine Verringerung kontrollierter Prozesse zugunsten automatisierter Teilprozesse zurückgeführt. Doch welche Prozeßeigenschaften zeigen einen solchen Lerneffekt an? Einen möglichen Weg zur Beantwortung dieser Frage sehen wir in der Analyse prozeßbegleitender funktionaler Kooperationen zwischen Hirnregionen und ihrer Veränderung durch Übung. In 2 EEG-Studien wird die Annahme getroffen, daß sich hoher kognitiver Aufwand für Kontroll- und Steuerprozesse im Arbeitsgedächtnis in besonders starken Synchronisationen zwischen Regionen des Frontal- und des Parietalbereiches widerspiegelt. Die Erwartung, daß eine Aufwandsreduktion durch Übung mit einer Verringerung solcher Synchronisationen einhergeht, ließ sich auf der Basis einer EEG-Kohärenzanalyse empirisch bestätigen. Gleichzeitig mit einer Verringerung der Stärke dieser interregionalen Synchronisation wurde eine Erhöhung der Stärke der lokalen Synchronisation in parietalen Bereichen gefunden. Das könnte dahingehend interpretiert werden, daß der durch Übung teilweise automatisierte Lösungsprozeß mehr und mehr in parietalen Regionen stattfindet und damit die Exekutive von ihrer Kontrollfunktion entlastet wird.

Fur die Untersuchung ergonomischer Fragestellungen bietet sich der Einsatz beruhrungsloser Blickerfassungssysteme an. Am FKIE wird zurzeit das System SmartEye Pro verwendet, um Kopfstellung, Blickrichtung und Bewegungen des Augenlides von Probanden in Echtzeit zu erfassen. In zwei Vorstudien wurden die Auswirkung verschiedener Kalibrierungseinstellungen auf die Trackingqualitat und die Qualitat der Messung von Sakkaden und Fixationen evaluiert. Es zeigte sich, dass das System geeignet ist, statistische Aussagen in Bezug auf Blickbewegungen und Lidschlussverhalten zu generieren. Jedoch ist die Bestimmung von Sakkaden- und Fixationsparametern nur eingeschrankt moglich. Unter Berucksichtigung dieser Restriktionen wird das System zurzeit in einem Verbundforschungsprojekt mit der Deutschen Sporthochschule Koln und dem Zentralen Institut des Sanitatsdienstes der Bundeswehr Koblenz zur Erfassung der psycho-physiologische Leistungsfahigkeit von Soldaten verwendet.

Six patients with Parkinson's disease (PD) reporting unusually fast or sudden onset of sleep under the addition of dopamine agonists to a previous levodopa-containing therapy were examined using a sleep-wake diary, the Epworth sleepiness scale (ESS), polysomnography, multiple sleep latency tests (MSLT), a standardized vigilance test, and driving simulation. In all patients, ESS scores were increased and polysomnography showed disruption of the sleep pattern, a tendency towards poor sleep efficiency, and reduced proportions of slow- wave and rapid eye movement sleep. Pathological results in the MSLT or the vigilance test were obtained in five cases. For evaluation of driving performance, the standard deviation from the mean lane position during driving simulation was calculated. Three of five patients had clearly increased mean SDLP values. With respect to the measurement of daytime sleepiness (ESS, MSLT, vigilance test, and driving simulation), each patient had pathological results in at least two of these examinations. However, only a limited transfer of the routine vigilance assessment to driving performance was possible. In summary, this pilot study indicates that unusually fast or sudden onset of sleep in PD patients is a phenomenon of daytime sleepiness.

Experiment and methods: Three well trained subjects carried out two different tasks: categorization and pattern comparison. Two kinds of stimuli were given in blocks: words and pictures. The two words or two pictures were presented with an interstimulus interval on a computer screen. For pattern comparison the subject has to decide about the identity of the two words or pictures. In case of categorization the subjects have to classify the two words or pictures. Thereby a category concept must be activated in contrast to pattern comparison. The EEG was recorded from 19 scalp electrodes (10 /20 system, ear lob reference, 256 Hz). Only artifact-free trials with correct positive answers were included in further analysis. Instantaneous coherence analysis (see e.g. Schack et al. 1999) was performed for 39 electrode pairs. The frequency band 13-20 Hz allowed the best discrimination between categorization and pattern comparison. Therefore, the time courses of coherence with regard to this frequency band were analyzed. Maximal coherence values were calculated for each trial and each electrode pair within the time interval from the presentation of the second item up to the end of the task. On the basis of calculating the correlation between the coherence vectors of all pairs of time points within the same time interval the single trials were subdivided into segments with stable coherence values. The segments were clustered into six classes. The time points of beginning, the duration and the mean coherence values of the segments of each cluster were calculated. Results: − Subjects need the same reaction time for classifying words and pictures. − The values of maximal coherence for the electrode pairs T3/C3, C3/Cz, T3/T5, C3/P3, F3/Pz are significantly higher for categorization than for pattern comparison both for word and for picture representation. At the same time they are not different with regard to the kind of stimulus both for categorization and for pattern comparison. − The distribution of segments of the cluster with high coherence values within the left hemisphere differs extremely with regard to the modality both for presentation of words and pictures (see Fig.1).