Facilitatory Effect of Intermittent Repetitive Transcranial Magnetic Stimulation on Perceptual Distortion of the Face.

Orofacial pain patients often report that the painful facial area is "swollen" without clinical signs - known as perceptual distortion (PD). The neuromodulatory effect of facilitatory repetitive transcranial magnetic stimulation (rTMS) on PD in healthy individuals was investigated, to provide further support that the primary somatosensory cortex (SI) is involved in facial PD. Participants were allocated to active (n = 26) or sham (n = 26) rTMS group in this case-control study.

Low-frequency rTMS inhibits the anti-depressive effect of ECT. A pilot study.

Objective: Low-frequency repetitive transcranial magnetic stimulation (rTMS) of the prefrontal cortex has been shown to have a statistically and clinically significant anti-depressant effect. The present pilot study was carried out to investigate if right prefrontal low-frequency rTMS as an add-on to electroconvulsive therapy (ECT) accelerates the anti-depressant effect and reduces cognitive side effects.

Methods: In this randomised, controlled, double-blind study, thirty-five patients with major depression were allocated to ECT+placebo or ECT+low-frequency right prefrontal rTMS.

Effect of repetitive transcranial magnetic stimulation on altered perception of One's own face.

Background: Chronic orofacial pain (COP) patients often perceive the painful face area as "swollen" without clinical signs; such self-reported illusions of the face are termed perceptual distortion (PD). The pathophysiological mechanisms underlying PD remain elusive.

Objective: To test the neuromodulatory effect of repetitive transcranial magnetic stimulation (rTMS) on PD in healthy individuals, to gain insight into the cortical mechanisms underlying PD.

[Post-concussion syndrome is a neuro-cognitive condition].

Post-concussion syndrome (PCS) is often caused by an uncomplicated mild head injury but followed by long-lasting somatic, cognitive and psychiatric symptoms. For many years PCS has been an area of controversy between clinicians. New diagnostic techniques and clinical researches has shed light to some neurobiological aspects behind PCS.

[Repetitive transcranial magnetic stimulation treatment for post-traumatic stress disorder].

Approximately 10% of combat soldiers and 30% of rape victims develop post-traumatic stress disorder (PTSD). Repetitive transcranial magnetic stimulation (rTMS) is already known to be safe in depression treatment. Research results of the past 15 years indicate that rTMS induced to the right dorsolateral prefrontal cortex may have a potential to treat the symptoms of PTSD.

Capillary dysfunction: its detection and causative role in dementias and stroke.

In acute ischemic stroke, critical hypoperfusion is a frequent cause of hypoxic tissue injury: As cerebral blood flow (CBF) falls below the ischemic threshold of 20 mL/100 mL/min, neurological symptoms develop and hypoxic tissue injury evolves within minutes or hours unless the oxygen supply is restored. But is ischemia the only hemodynamic source of hypoxic tissue injury? Reanalyses of the equations we traditionally use to describe the relation between CBF and tissue oxygenation suggest that capillary flow patterns are crucial for the efficient extraction of oxygen: without close capillary flow control, "functional shunts" tend to form and some of the blood's oxygen content in effect becomes inaccessible to tissue. This phenomenon raises several questions: Are there in fact two hemodynamic causes of tissue hypoxia: Limited blood supply (ischemia) and limited oxygen extraction due to capillary dysfunction? If so, how do we distinguish the two, experimentally and in patients? Do flow-metabolism coupling mechanisms adjust CBF to optimize tissue oxygenation when capillary dysfunction impairs oxygen extraction downstream? Cardiovascular risk factors such as age, hypertension, diabetes, hypercholesterolemia, and smoking increase the risk of both stroke and dementia.

Brain energy metabolism and blood flow differences in healthy aging.

Cerebral metabolic rate of oxygen consumption (CMRO(2)), cerebral blood flow (CBF), and oxygen extraction fraction (OEF) are important indices of healthy aging of the brain. Although a frequent topic of study, changes of CBF and CMRO(2) during normal aging are still controversial, as some authors find decreases of both CBF and CMRO(2) but increased OEF, while others find no change, and yet other find divergent changes. In this reanalysis of previously published results from positron emission tomography of healthy volunteers, we determined CMRO(2) and CBF in 66 healthy volunteers aged 21 to 81 years.

Assessing response to stroke thrombolysis: validation of 24-hour multimodal magnetic resonance imaging.

Background: Imaging is used as a surrogate for clinical outcome in early-phase stroke trials. Assessment of infarct growth earlier than the standard 90 days used for clinical end points may be equally accurate and more practical.

Objective: To compare assessment of the effect of reperfusion therapies using 24-hour vs day 90 magnetic resonance imaging.

Variable ATP yields and uncoupling of oxygen consumption in human brain.

The distribution of brain oxidative metabolism values among healthy humans is astoundingly wide for a measure that reflects normal brain function and is known to change very little with most changes of brain function. It is possible that the part of the oxygen consumption rate that is coupled to ATP turnover is the same in all healthy human brains, with different degrees of uncoupling explaining the variability of total oxygen consumption among people. To test the hypothesis that about 75% of the average total oxygen consumption of human brains is common to all individuals, we determined the variability in a large group of normal healthy adults.

[The effect of vitamin D on neuropsychiatric conditions].

Vitamin D receptors have recently been identified in immune cells as well as various parts of the brain. Vitamin D deficiency seems to be involved in the patho-immunological process of multiple sclerosis. Hypovitaminosis D has also been associated with different psychiatric conditions, including depression and schizophrenia.

Carbogen inhalation increases oxygen transport to hypoperfused brain tissue in patients with occlusive carotid artery disease: increased oxygen transport to hypoperfused brain.

Hyperoxic therapy for cerebral ischemia reduces cerebral blood flow (CBF) principally from the vasoconstrictive effect of oxygen on cerebral arterioles. Based on a recent study in normal volunteers, we now claim that the vasodilatory effect of carbon dioxide predominates when 5% CO(2) is added to inhaled oxygen (the mixture known as carbogen). In the present study, we measured CBF by positron emission tomography (PET) during inhalation of test gases (O(2), carbogen, and atmospheric air) in healthy volunteers (n = 10) and in patients with occlusive carotid artery disease (n = 6).

[11C]Mirtazapine binding in depressed antidepressant nonresponders studied by PET neuroimaging.

Rationale: Lack of benefit from antidepressant drug therapy is a major source of human suffering, affecting at least 25% of people with major depressive disorder. We want to know whether nonresponse to antidepressants can be linked to aberrant neuroreceptor binding.

Objective: This study aims to assess the antidepressant binding in brain regions of depressed nonresponders compared with healthy controls.

Safety and efficacy of MRI-based selection for recombinant tissue plasminogen activator treatment: responder analysis of outcome in the 3-hour time window.

Introduction: The use of MRI may alter the target population for intravenous recombinant tissue plasminogen activator (rtPA) treatment relative to conventional CT. If selection changes, it remains crucial to demonstrate safety and efficacy of rtPA for the overall population, as well as in subpopulations hypothesized to benefit from MRI.

Materials And Methods: Clinical outcome and incidence of symptomatic intracerebral hemorrhage (ICH) was recorded in 112 consecutive patients treated with intravenous rtPA (0-3 h) with MRI as first-choice imaging modality.

Feasibility and logistics of MRI before thrombolytic treatment.

Objectives: The study analyzes feasibility and time-delays in Magnetic resonance imaging (MRI) based thrombolysis and estimate the impact of MRI on individual tissue plasminogen activator (rtPA) treatment.

Materials And Methods: Feasibility of MRI and time logistics were prospectively recorded in patients referred with presumed acute stroke over a 2 year time period. Door-to-needle-times (DNT) were compared with those of patients treated with rtPA after conventional CT during the same time period, and to published open label studies.

Improvement of brain tissue oxygenation by inhalation of carbogen.

Hyperoxic therapy for cerebral ischemia is suspected to reduce cerebral blood flow (CBF), due to the vasoconstrictive effect of oxygen on cerebral arterioles. We hypothesized that vasodilation predominates when 5% CO(2) is added to the inhaled oxygen (carbogen). Therefore, we used positron emission tomography (PET) to measure CBF and cerebral metabolic rate of oxygen (CMRO(2)) during inhalation of test gases (O(2), CO(2), carbogen and atmospheric air) in 10 healthy volunteers.

Neuroimaging of mirtazapine enantiomers in humans.

Introduction: Mirtazapine is a racemic antidepressant with a multireceptor profile. Previous studies have shown that the enantiomers of mirtazapine have different pharmacologic effects in the brain of laboratory animals.

Materials And Methods: In the present study, we used positron emission tomography (PET) and autoradiography to study effects of (R)- and (S)-[(11)C]mirtazapine in the human brain.

MRI detection of early blood-brain barrier disruption: parenchymal enhancement predicts focal hemorrhagic transformation after thrombolysis.

Background And Purpose: Blood-brain barrier disruption may be a predictor of hemorrhagic transformation (HT) in ischemic stroke. We hypothesize that parenchymal enhancement (PE) on postcontrast T1-weighted MRI predicts and localizes subsequent HT.

Methods: In a prospective study, 33 tPA-treated stroke patients were imaged by perfusion-weighted imaging, T1 and FLAIR before thrombolytic therapy and after 2 and 24 hours.

Normalization in PET group comparison studies--the importance of a valid reference region.

Introduction: In positron emission tomography (PET) studies of cerebral blood flow (CBF) and metabolism, the large interindividual variation commonly is minimized by normalization to the global mean prior to statistical analysis. This approach requires that no between-group or between-state differences exist in the normalization region. Given the variability typical of global CBF and the practical limit on sample size, small group differences in global mean easily elude detection, but still bias the comparison, with profound consequences for the physiological interpretation of the results.

[Imaging of the pathophysiology in acute stroke].

Recent developments in neuroimaging have changed the diagnostic aspect of acute stroke and improved our understanding of stroke pathophysiology. Both diffusion weighted MR imaging and CT are capable of detecting the infarcted volume damaged by cytotoxic edema. However, within six hours of stroke onset, DWI has both higher sensitivity and specificity than CT.

[Thrombolysis of apoplexy patients. A year's experience and results in Aarhus Hospital].

Introduction: Treatment of acute stroke with thrombolysis within three hours is a challenging aspect of the organization of state-of-the-art stroke care. Indication for thrombolysis is based on studies where CT was used as a diagnostic tool. MR-based techniques are in some aspects superior to CT, though the scan times are longer.

Ischemic injury detected by diffusion imaging 11 minutes after stroke.

A 78-year-old woman suffered a stroke inside a magnetic resonance scanner while being imaged because of a brief transient ischemic attack 2 hours earlier. Diffusion-weighted images obtained 11 minutes after stroke showed tissue injury not found on initial images. The data show early, abrupt diffusion changes in hypoperfused tissue, adding to our understanding of the progression of microstructural abnormalities in the hyperacute phase of stroke.