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(Stroke. 2007;38:3186.)
© 2007 American Heart Association, Inc.
Original Contributions |
From the Department of Psychiatry (K.-J.B., N.S., H.S.), the Institute of Physiology I (M.K.B.), the Institute of Diagnostic and Interventional Radiology (H.J.M.), and the Department of Neurology (C.T.), Friedrich-Schiller-University Jena, Jena, Germany.
Correspondence to Karl-Jürgen Bär, MD, Department of Psychiatry, Friedrich-Schiller-University Jena, Philosophenweg 3, 07743 Jena, Germany. E-mail Karl-Juergen.Baer{at}med.uni-jena.de
Background and Purpose— Recent reports suggest that vascular factors play a crucial role in the development and progression of Alzheimers disease. We aimed to assess vasomotor reactivity in patients with Alzheimers disease and vascular dementia due to microangiopathy using transcranial Doppler sonography and near-infrared spectroscopy during a CO2 exposition task.
Methods— The normalized CO2 reactivity assessed at the middle cerebral artery and the oxygenated and deoxygenated hemoglobin of the frontal cortex were obtained. To investigate the impact of cholinergic deficiency known for Alzheimers disease on vasomotor reactivity, both groups were reinvestigated during treatment with the acetylcholine esterase inhibitor galantamine.
Results— Transcranial Doppler analysis revealed significantly reduced normalized CO2 reactivity for Alzheimers disease and vascular dementia. Vasomotor reactivity assessed by near-infrared spectroscopy was decreased in patients with vascular dementia, but not in Alzheimers disease. Galantamine treatment showed a beneficial effect, normalizing these parameters close to age-matched control levels.
Conclusions— Our results suggest that Alzheimers disease is associated with a lack of vasomotor reactivity, which might be associated with disturbed autoregulation indicating a potential risk for a decreased protection of brain tissue against blood pressure changes. Additionally, a diminished increase of cortical oxygenated hemoglobin during the CO2 test was apparent in patients with vascular dementia. Galantamine treatment influenced vascular reactivity in the CO2 test, thus providing evidence for the cholinergic deficiency, thereby adding to vascular dysregulation in Alzheimers disease, but also indicating an important role of cholinergic system dysfunction for vascular dementia.
Key Words: autonomic nervous system Alzheimers disease dementia near-infrared spectroscopy transcranial Doppler sonography
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