Search results for "Central nervous"
showing 10 items of 899 documents
How angioarchitecture of cerebral arteriovenous malformations should influence the therapeutic considerations.
1995
PURPOSE To evaluate the angioarchitectural criteria of complex cerebral arteriovenous malformations (AVMs), concerning the risk of hemorrhage and therapy planing. METHODS The magnetic resonance (MR) imaging and neuroangiographic findings of 227 AVMs (223 patients) were retrospectively evaluated. Statistical analysis was used to define the relative frequency of these lesions for hemorrhage in correlation with various parameters (i.e. age of the patient, size, location, associated aneurysms). RESULTS Onset of symptoms was between 21 and 40 years of age in 50% of cases. The ratio of centrally to convexially located lesions was 1:2. Convexial AVMs are classified by MR imaging into sulcal and gy…
Stereotactically guided cavernous malformation surgery.
1996
The incidence of a significant hemorrhage in the natural history of cavernomas is below 1% per year, but the risk of a second hemorrhage in patients with initial bleeding cavernomas is between 14% and 29%. In the light of these figures, all cavernomas ought to be resected if surgical-related morbidity can be minimized. Stereotactically guided neurosurgery offers the advantage of planning the least traumatic approach before craniotomy due to the knowledge of the exact localisation of the lesion. During a 2-year period 12 patients (age 16-54 years) with intracranial supratentorial cavernomas (size 0.5-1.8 cm) were treated by stereotactically guided microsurgery. The cavernomas were seated in …
Disturbed brain activation during a working memory task in drug-naive adult patients with ADHD.
2010
Neuroimaging studies in attention-deficit/hyperactivity disorder (ADHD) have shown abnormalities in several brain areas including the frontostriatal circuitry and were mostly conducted in children and adolescents. We investigated 30 never-medicated adult ADHD patients (16 males) and 30 matched healthy control individuals. Functional magnetic resonance imaging was acquired during a working memory paradigm (n-back). Group activation maps and group differences of activation were calculated using voxel-based analyses. The generic activation pattern was more extended in the control group. In ADHD patients, significantly decreased activation was found in the right inferior parietal cortex. Distur…
Habituation and laterality of orienting processes as reflected by slow negative waves
2000
The study is concerned with the question of whether the orienting wave (O-wave), a slow potential shift of the event-related brain potential, is a component of the orienting response (OR). As habituation is supposed to be the most important characteristic of the OR, we focussed particularly on any habituating aspect of the O-wave. Results suggest that its bilateral distribution over midfrontal areas might constitute such a link relating the O-wave to orienting activity. Hemispheric asymmetry linearly decreased its right-sided predominance in response to repeated presentations of an initially novel auditory stimulus. A similar, concomitant diminution of the skin conductance response (SCR) oc…
Correlation of cerebral blood flow and treatment effects of repetitive transcranial magnetic stimulation in depressed patients.
2002
The aims of this study were to: (1) assess the effects of repetitive transcranial magnetic stimulation (rTMS) on brain activity in depressed patients as measured by single photon emission tomography (SPECT); (2) evaluate the predictive value of brain SPECT on the antidepressant efficacy of rTMS. Patients (n=17) received 1600 rTMS stimuli at a rate of 10 Hz, 5 days per week for 2 weeks to the left dorsolateral prefrontal cortex. Whole brain SPECT data were acquired using Tc99m-Bicisate. Regional cerebral blood flow (rCBF) was correlated with the % change in the 28-item Hamilton Depression Rating Scale Score (Δ-HDRS) and a semiquantitative region of interest (ROI) analysis was conducted. Prio…
Maturation of near-field and far-field somatosensory evoked potentials after median nerve stimulation in children under 4 years of age
2000
Abstract Objectives : The maturation of subcortical SEPs in young children. Methods : Median nerve SEPs were recorded during sleep in 42 subjects aged 0–48 months. Active electrodes were at the ipsilateral Erb's point, the lower and upper dorsal neck, and the frontal and contralateral centroparietal scalp; reference electrodes were at the contralateral Erb's point, the ipsilateral earlobe and the frontal scalp; bandpass was 10–3000 Hz. The peaks were labelled by their latencies in adults. Results : The peak latencies of N9 (brachial plexus potential) decreased exponentially with age during the first year, but increased with height thereafter. The interpeak latencies (IPLs) N9–N11, which mea…
Prevalence of Apolipoprotein E Alleles in Healthy Subjects and Survivors of Ischemic Stroke
1998
Background and Purpose —The ε4 allele of the apolipoprotein E (apoE) has been related to the occurrence of myocardial infarction, but its association with ischemic stroke is controversial. We have evaluated the relation between apoE alleles and the occurrence of cerebrovascular ischemia. Methods —The apoE ε genotypes of 100 patients with a documented history of ischemic stroke without clinically apparent dementia (stroke+) and 108 subjects without such history (stroke−) were determined. The relative frequency of the apoE alleles and genotypes was estimated in 398 healthy subjects aged <40 years from the same ethnic background. Results —The frequency of the apoE ε4 allele in stroke+ (0.1…
Acute Alcohol Effects on Neuronal and Attentional Processing: Striatal Reward System and Inhibitory Sensory Interactions under Acute Ethanol Challenge
2004
The acute influence of ethanol on cerebral activity induces complex psycho-physiological effects that are considerably more pronounced during acute ethanol influx than during maximal blood alcohol concentration (elimination phase). Despite the psychiatric and forensic relevance of these different ethanol effects, the underlying neuronal mechanisms are still unclear. In total, 20 male healthy volunteers were investigated each with three different experimental conditions in a randomized order using an intravenous ethanol challenge (40 g bolus infusion): during influx phase, elimination phase, and under placebo condition. During and after the ethanol (or placebo) infusion, neuropsychological t…
Hemispheric cerebellar rTMS to treat drug-resistant epilepsy: case reports.
2005
Electrical stimulation of the cerebellar cortex by implanted electrodes has been shown to ameliorate refractory epilepsy. We investigated the potential therapeutic role of high-frequency cerebellar rTMS in patients affected by refractory epilepsy due to single or multiple foci. Six patients, three with single and three with multiple epileptic foci, underwent 20 rTMS sessions. Each session was given daily, excluding weekends, and consisted of two trains of 50 stimuli (5 Hz frequency and 90% motor threshold intensity), separated by 50s interval. rTMS was delivered through a focal coil (2 cm below and lateral to the inion) bilaterally in patients with multiple foci (two trains for hemisphere: …
Magnetic resonance findings in scuba diving-related spinal cord decompression sickness
1997
Scuba diving is associated with risk of severe decompression sickness (DCS type II), which results from rapid reduction of the environmental pressure sufficient to cause the formation into tissue or blood of inert gas bubbles previously loaded within tissues as a soluble phase. DCS type II constitutes a unique subset of ischemic insults to the central nervous system (CNS) with primarily involvement of the spinal cord. Ten patients with diving-related barotrauma underwent neurologic examination. Two of them presented progressive sensory and motor loss in the extremities at admission and were presumed affected by spinal cord DCS. Magnetic resonance imaging (MRI) demonstrated abnormalities in …