René Jansen

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Cerebral autoregulation (CA) refers to the properties of the brain vascular bed to maintain cerebral perfusion despite changes in blood pressure (BP). Whereas classic studies have assessed CA during changes in BP that have a gradual onset, dynamic studies quantify the fast modifications in cerebral blood flow (CBF) in relation to rapid alterations in BP.(More)
BACKGROUND The differentiation of Alzheimer's disease (AD) from vascular dementia (VaD) is hampered by clinical diagnostic criteria with disappointing sensitivity and specificity. The objective of this study was to investigate whether cerebrospinal fluid (CSF) levels of total tau protein (t-tau), amyloid beta42 protein (Abeta42), and tau phosphorylated at(More)
Near infrared spectroscopy (NIRS) and functional magnetic resonance imaging (fMRI) both allow non-invasive monitoring of cerebral cortical oxygenation responses to various stimuli. To compare these methods in elderly subjects and to determine the effect of age on cortical oxygenation responses, we determined motor-task-related changes in deoxyhemoglobin(More)
The treatment of Alzheimer's disease (AD) with cholinesterase inhibitors (ChEIs) is based on the cholinergic hypothesis. This hypothesis fails to account for the global nature of the clinical effects of ChEIs, for the replication of these effects in other dementias, and for the strong and unpredictable intraindividual variation in response to treatment.(More)
This review addresses recent developments in amyloid beta (Abeta), total tau (t-tau), and phosporylated tau (p-tau) protein analysis, in cerebrospinal fluid (CSF) and plasma as biomarkers for dementia. Recent research focused on the protection of patients with mild cognitive impairment (MCI) into dementia and the differential diagnosis of Alzheimer's(More)
Recently it was shown that blood pressure (BP) in the elderly may decrease after a meal. The pathophysiologic mechanism of this phenomenon is unknown. It has been suggested that a failure of insulin-mediated sympathetic nervous system activation plays a role. To evaluate the role of endogenous insulin, the effects of oral glucose and oral fructose loading(More)
BACKGROUND Neurofilament (NF) proteins are major cytoskeletal constituents of neurons. Increased CSF NF levels may reflect neuronal degeneration. OBJECTIVE To investigate the diagnostic value of CSF NF analysis to discriminate in relatively young dementia patients between frontotemporal lobe degeneration (FTLD) and early onset Alzheimer's disease (EAD;(More)
In the elderly, standing can frequently be accompanied by blood pressure (BP) changes and cerebral symptoms such as dizziness, fall, or even syncope, but this may vary from day-to-day. Therefore, we aimed to investigate the reproducibility of orthostatic responses of cerebral cortical oxygenation and systemic haemodynamics in elderly subjects. In 27 healthy(More)
BACKGROUND This study describes orthostatic and postprandial hypotension in elderly Parkinsonian patients and evaluates the effect of levodopa therapy on orthostatic and postprandial hypotension in these patients. METHODS Seventeen elderly patients with a clinical diagnosis of Parkinson's disease or Parkinsonism based on the U.K. Parkinson's Disease(More)
BACKGROUND AND PURPOSE With increasing age, assuming the upright position is more often accompanied by symptoms such as dizziness and lightheadedness, possibly as a result of a diminished oxygen supply to the brain due to impaired cerebral autoregulation. We aimed to quantify postural changes in cerebral oxygenation and systemic hemodynamics in healthy(More)