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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 121 (1998), S. 471-477 
    ISSN: 1432-1106
    Keywords: Key words Posture ; Posturography ; Balance ; Vision ; Psychophysics ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The present study investigates the efficacy of visual stabilisation of posture for different spatial frequencies of a visual stimulus. Circular sine wave gratings were used to analyse the correlation between perception of motion in depth and stabilisation of fore-aft sway by the mechanism of detecting changes in target size. Body sway was recorded by a force-measuring platform (series A) and, in addition, by simultaneous tracking of infrared markers fixed to the subject’s body (series B). Mean velocity and amplitude (RMS) of body sway were calculated in both sagittal (a–p) and lateral (l–r) planes. Sagittal sway was of least magnitude when viewing contrast gratings with lowest thresholds, whereas higher thresholds resulted in increasing sway parameters. As intended by the design of the stimuli, sagittal sway was correlated closer with the stabilising effect exerted by the different stimuli than was lateral sway. Sway velocity was reduced more efficiently, however, with a lower correlation with the psychophysical transfer function, than was RMS sway. Since sway velocity measured by the platform is suggested to depend to a greter extent on dynamic muscle forces generated at each individual body site the results indicate that visual information can be used to reduce and thereby optimise dynamic muscle action (sway velocity) even though static body sway is either not or less reduced. A comparable economisation of sway velocity but not of RMS sway was also seen at the end of posture investigations, indicative of positive training effects.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0942-0940
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 8985-8992 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A homogeneous mixture of iso-butoxyethanol/water of noncritical composition is brought from a state in the thermodynamic stable region of its phase diagram in the vicinity of its lower critical point to a metastable state close to the binodal curve by a fast pressure jump. It reaches its thermodynamic equilibrium state by separating into two coexisting liquid phases of different compositions. The emerging second liquid phase is formed by nucleation and growth of droplets. After a short transition time, the early stages of the diffusion limited growth of the droplets of the emerging second liquid phase are studied by light scattering (Mie scattering). The experiments are carried out as function of the temperature difference (Tp−Tc) along the two branches of the liquid/liquid coexistence curve (Tc, critical temperature; Tp, temperature of phase separation). The mutual diffusion coefficient D extracted from the kinetics of the droplet growth decreases approaching the critical point along the two branches of the binodal curve. The values of D obtained in this way are in good agreement with those characterizing the dynamics of concentration fluctuations in each of the coexisting phases in thermodynamic equilibrium monitored by dynamic light scattering experiments. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The phase separation kinetics of fluid mixtures of polyethylene glycol/polypropylene glycol (a system with an upper critical mixing point) is studied after a pressure jump from the homogeneous one-phase region into the two-phase region of the phase diagram. The growth of the emerging domains of the coexisting phases is observed by small angle laser light scattering. In additional measurements the pressure dependence of the phase separation temperature is analyzed. In the kinetic experiments the time-dependent structure function is detected for a mixture with near-critical as well as for a mixture with off-critical composition. For the near-critical mixture an increase of the maximum of the scattering intensity with time has been found, which qualitatively is typical for the intermediate to late stages of spinodal decomposition. A closer analysis of the late stages reveals two maxima in the structure factor with their own set of growth exponents for the scattering vector and for the intensity. The data of the low q maximum are compatible with a two-dimensional growth process which is interpreted as a demixing process in a wetting layer. The data of the high q maximum are according to a three-dimensional process. It is assumed that this maximum reflects the demixing process in the bulk phase. The values of the three-dimensional growth exponents, which are considered to be late stage values, are not compatible with observations on other fluid systems but are close to those for solid systems or, in general, for systems with suppressed hydrodynamic interactions. For the mixture with an off-critical composition the structure function remains constant for larger times (pinning effect). The occurrence of a pinning effect in samples of relatively low molecular weight Mw (Mw≤1019 g/mol) and the apparently suppressed hydrodynamic interactions in a fluid sample are explained with specific interactions caused by hydrogen bonding (i.e., transient entanglement or a dynamic network). © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Der Nervenarzt 68 (1997), S. 836-838 
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Epilepsie ; Antiepileptika ; Topiramat ; Key words Epilepsy ; Anticonvulsants ; Topiramate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Topiramate is a new antiepileptic drug, which is not yet marketed in Germany. The anticonvulsive activity is probably mediated by sodium-channel blockade combined with gabaergic and weak antiglutamtergic properties. We investigated 23 patients with partial seizures in this open prospective study. The efficacy was analysed under stable concurrent antiepileptic drugs. Two of the patients became seizure free. Ten patients had a reduction of seizure frequency of at least 50%. The responder rate was 57%. The maximum daily dosages were 400 to 850 mg. Side-effects without relationship to dose were nervousness and aggression. In two patients an psychotic episode occurred. Dose-related side-effects were ataxia, dizziness, somnolence and dysarthria. This study is underlining that topiramate is efficacious in the treatment of partial onset seizures but also associated with a narrow therapeutic width.
    Notes: Zusammenfassung Topiramat ist eine neue, mit anderen Antiepileptika strukturell nicht verwandte Substanz, die bisher in Deutschland nicht zugelassen ist. Die klinische Wirkung wird wahrscheinlich über einen Na+-Kanal blockierenden Effekt, eine Aktivierung der Gammaaminobuttersäure-(GABA)-rezeptoren mit Erhöhung der GABAA-abhängigen Chloridströme und eine schwache antiglutamaterge Wirkung vermittelt. Wir haben 23 erwachsene Patienten mit einer fokalen Epilepsie in einer offenen prospektiven Studie mit Topiramat behandelt. Unter einer konstanten Begleitmedikation wurde die Wirksamkeit und Verträglichkeit untersucht. Zwei Patienten wurden anfallsfrei, bei 10 Patienten kam es mindestens zu einer Reduktion der Anfallshäufigkeit um 50%. Insgesamt profitierten somit 57% der Patienten deutlich. Die maximalen Topiramatdosen lagen zwischen 400 und 850 mg/Tag. Als Nebenwirkungen traten bei zu schneller Eindosierung eine erhöhte Nervosität und Aggressivität bis hin zu einer psychotischen Episode auf. Dosisabhängige Nebenwirkungen waren Ataxie, Schwindel, Müdigkeit und Dysarthrie. Topiramat stellte sich in dieser Studie bei einer engen therapeutischen Breite als gut wirksam dar.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Epilepsie ; Klassifikation ; Anfälle ; Key words Epilepsy ; Seizure ; Classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Recent advances in epileptology and epilepsy surgery require revision of the currently used International Classification of Epileptic Seizures, which was published 1981. We present a classification of epileptic seizures which is based purely on the clinical seizure semiology. The advantages of a semiological seizure classification are stressed.
    Notes: Zusammenfassung In den letzten Jahren wird zunehmend diskutiert, daß die 1981 vorgestellte Klassifikation epileptischer Anfälle der Internationalen Liga gegen Epilepsie revisionsbedürftig ist. Insbesondere von epilepsiechirurgisch tätigen Zentren wurden Verbesserungsvorschläge gemacht. Die hier vorgestellte semiologische Anfallsklassifikation basiert ausschließlich auf der klinischen Anfallssemiologie und bietet theroetische und praktische Vorteile, die im einzelnen erläutert werden. Sie soll als Diskussionsgrundlage dafür dienen, neue Aspekte in die Klassifikation epileptischer Anfälle einzuführen, die praktische Konsequenzen für die Diagnostik und Behandlung der Patienten haben.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Der Nervenarzt 69 (1998), S. 127-130 
    ISSN: 1433-0407
    Keywords: Schlüsselwörter Juvenile myoklonische Epilepsie ; Epilepsie ; Elektroenzephalographie ; Key words Juvenile myoclonic epilepsy ; Epilepsy ; Electroencephalography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Juvenile myoclonic epilepsy (JME) was de-scribed electroclinically by Janz and Christian in 1957 and consists of myoclonic jerks in varying combination with the absence of seizures and generalized tonic-clonic seizures, a typical circadian distribution on awakening, sleep deprivation, alcohol consumption and flickering stimuli as characteristic precipitating factors, typical EEG abnormalities with generalized epileptiform discharges, normal physical and neuroradiological findings, and often a family history of epilepsy. Although the misdiagnosis of this well-classified and easily treatable syndrome is supposed to occur rarely in Germany, we retrospectively investigated how often the wrong initial classification had been made among patients who were finally treated in our outpatient epilepsy unit. Between 1993 and 1995, 30 patients with a typical JME-like symptom constellation were identified who had been misdiagnosed initially. In all patients, localization-related epilepsy had been classified, although regional EEG abnormalities were rare (n=5). All patients reported the typical circadian distribution, abnormal neuroradiological findings were absent, and typical EEG abnormalities were present in all cases. Under treatment with appropiate antiepileptic drugs 97% of the patients became almost completely seizure-free. Even 40 years after the first description of the syndrome, JME is an underdiagnosed illness. The generally positive course underlines the importance of its correct identification.
    Notes: Zusammenfassung Die 1957 erstmals beschriebene juvenile myoklonische Epilepsie (JME) ist ein klar charakterisiertes Epilepsiesyndrom mit Myoklonien in fakultativer Kombination mit Absencen und generalisierten tonisch-klonischen Anfällen. Die Anfälle sind an die Aufwachphase gebunden und typischerweise durch Schlafentzug, Alkohol und Flickerlicht provozierbar. Als elektroenzephalographisches Korrelat werden generalisierte Spike-wave- und Poly-spike-wave-Komplexe nachgewiesen. Der klinisch-neurologische Untersuchungsbefund sowie die neuroradiologischen Befunde sind in aller Regel normgerecht. Entgegen der Ansicht, daß die JME insbesondere in Deutschland gut bekannt ist und selten verkannt wird, haben wir in Epilepsieambulanz zwischen 1993 und 1995 immer wieder Patienten gesehen, die initial falsch klassifiziert worden waren. Wir konnten zwischen 1993 und 1995 30 Patienten mit einer JME identifizieren, die initial falsch diagnostiziert wurden. In allen Fälle war die Epilepsie bis zum Aufsuchen unserer Epilepsieambulanz als fokal klassifiziert worden, und dieses, obwohl regionale EEG-Veränderungen nur selten waren (n=5). Alle Patienten berichteten über typische Anfallsprovokationen sowie eine tageszeitliche Bindung der Anfälle. Unter einer adäquaten Therapie wurden 97% der Patienten bis auf vereinzelte Myoklonien anfallsfrei. Auch 40 Jahre nach der Syndrombeschreibung ist die JME eine unterdiagnostizierte Erkrankung. Dabei zeigt die gute Therapierbarkeit der Patienten die Wichtigkeit der korrekten Diagnosestellung auf.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Annals of biomedical engineering 28 (2000), S. 1362-1369 
    ISSN: 1573-9686
    Keywords: Electroencephalography ; Epilepsy ; Neural networks ; Spike detection ; Kohonen feature map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Artificial neural networks are widely used for pattern recognition tasks. For spike detection in electroencephalography (EEG), feedforward networks trained by the backpropagation algorithm are preferred by most authors. Opposed to this, we examined the off-line spike detection abilities of a Kohonen feature map (KFM), which is different from feedforward networks in certain aspects. The EEG data for the training set were obtained from patients with intractable partial epilepsies of mesiotemporal (n = 2) or extratemporal (n = 2) origin. For each patient the training set for the KFM included the same patterns of background activity and artifacts as well as the typical individual spike patterns. Three different-sized networks were examined (15 × 15 cells, 25 × 25 cells, and 60 × 60 cells in the Kohonen layer). To investigate the quality of spike detection the results obtained with the KFM were compared with the findings of two board-certified electroencephalographers. Application of a threshold based on the partial invariance of spike recognition against translation of the EEG provided an average sensitivity and selectivity of 80.2% at crossover threshold (71%–86%) depending on the networksize and noise. Multichannel EEG processing in real time will be available soon. In conclusion, pattern-based automated spike detection with a KFM is a promising approach in clinical epileptology and seems to be at least as accurate as other more-established methods of spike detection. © 2000 Biomedical Engineering Society. PAC00: 8719Nn, 8780-y
    Type of Medium: Electronic Resource
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