Search PubMed⌕ Search

Biomedical subjects

Jørgen Alving

Publications and source records attributed to Jørgen Alving.

6 recordsLinked to original sources
PubMed2006

Source analysis of epileptic discharges using multiple signal classification analysis.

Multiple signal classification is an alternative to the traditional dipole fitting source analysis methods. Our aim was to assess the clinical usefulness of this algorithm and to compare the localization of the epileptiform electroencephalography discharges with the regions of altered cerebral blood flow in 10 patients with complex partial seizures undergoing preoperative investigation. We performed multiple signal classification analysis of ictal and interictal discharges, and registered single-photon emission computed tomography. Localization of the ictal, but not the interictal discharges, as determined by multiple signal classification analysis was consistent with the regions showing perfusion changes on the single-photon emission computed tomography. Multiple signal classification analysis is a promising tool in localizing foci in patients with complex partial seizures and may contribute to the preoperative evaluation.

Adult↗
PubMed2002

[Epilepsy surgery of Danish children 1996-2002].

INTRODUCTION: Epilepsy surgery is done in order to obtain seizure freedom or to reduce the number of epileptic seizures in selected patients not responding to medical treatment. Few Danish children have had this treatment, most probably because of some restrictions imposed by The Danish National Health Board. We present the results of the first 22 Danish children who have had epilepsy surgery. MATERIAL AND METHODS: All children up to the age of 15 operated from January 1st 1996 to May 1st 2002 are included. According to the guidelines of The Danish National Health Board, 17 children have been operated abroad because the epileptic focus was extratemporal or intracranial EEG-monitoring was necessary. Follow-up varied from five years and six months to one month. RESULTS: At the time of the operation, all children had a long-lasting medical intractable epilepsy. 18 children had daily seizures and 15 were mentally retarded. Multi-lobar resection was performed in ten, hemispherectomy in three and lobar resection in eight children. Total seizure-free outcome was seen in 12 children, whereas three only had simple partial seizures (totally 68 per cent). The remaining children had at least a 50 per cent seizure reduction. On an average, the cognitive function was unchanged one year after the surgery. The majority of the parents stated that the behaviour of the child had improved on one or more specific issues. One mother stated that to a certain degree she regretted the operation. In four children, an unexpected complication was registered (slight hemiparesis and a hemianopsia). DISCUSSION: The results documented that epilepsy surgery is effective for selected children in spite of long-lasting severe epilepsy. In order to alleviate the consequences of severe epilepsy it is, however, important to refer the patients early. There seems to be a need for more and early referrals for childhood epilepsy surgery in Denmark.

Adolescent↗
PubMed2002

Increased dopamine tone during meditation-induced change of consciousness.

This is the first in vivo demonstration of an association between endogenous neurotransmitter release and conscious experience. Using 11C-raclopride PET we demonstrated increased endogenous dopamine release in the ventral striatum during Yoga Nidra meditation. Yoga Nidra is characterized by a depressed level of desire for action, associated with decreased blood flow in prefrontal, cerebellar and subcortical regions, structures thought to be organized in open loops subserving executive control. In the striatum, dopamine modulates excitatory glutamatergic synapses of the projections from the frontal cortex to striatal neurons, which in turn project back to the frontal cortex via the pallidum and ventral thalamus. The present study was designed to investigate whether endogenous dopamine release increases during loss of executive control in meditation. Participants underwent two 11C-raclopride PET scans: one while attending to speech with eyes closed, and one during active meditation. The tracer competes with endogenous dopamine for access to dopamine D2 receptors predominantly found in the basal ganglia. During meditation, 11C-raclopride binding in ventral striatum decreased by 7.9%. This corresponds to a 65% increase in endogenous dopamine release. The reduced raclopride binding correlated significantly with a concomitant increase in EEG theta activity, a characteristic feature of meditation. All participants reported a decreased desire for action during meditation, along with heightened sensory imagery. The level of gratification and the depth of relaxation did not differ between the attention and meditation conditions. Here we show increased striatal dopamine release during meditation associated with the experience of reduced readiness for action. It is suggested that being in the conscious state of meditation causes a suppression of cortico-striatal glutamatergic transmission. To our knowledge this is the first time in vivo evidence has been provided for regulation of conscious states at a synaptic level.

Adult↗
PubMedDate not supplied

A cross-sectional study of epilepsy in Danish Labrador Retrievers: prevalence and selected risk factors.

The purpose of this study was to investigate the prevalence and selected risk factors of epilepsy, the proportion of dogs with epilepsy in remission, and the types of seizures in Danish Labrador Retrievers. A prospective cross-sectional study of epilepsy was conducted in 1999-2000. The study was carried out in 2 phases in a reference population consisting of 29,602 individuals. In phase 1, 550 dogs were selected by random sampling stratified by year of birth. A telephone interview was used to identify dogs with possible epilepsy. In phase 2, dogs judged during phase 1 as possibly suffering from epilepsy were further subjected to physical and neurologic examination, CBC, blood chemistry, and a questionnaire on seizure phenomenology. Seventeen dogs were diagnosed with epilepsy, yielding a prevalence of 3.1% (95% CI 1.6-4.6%) in the Danish population of Labrador Retrievers. A diagnosis of epilepsy was 6 times more probable in dogs >4 years (born before 1995) than in younger dogs (born between 1995 and 1999) (P = .004, relative risk = 6.5). No significant difference in risk between genders was observed, nor could any effect of neutering be proven statistically. The frequencies of primary generalized seizures and partial seizures (with or without secondary generalization) were 24 and 70%, respectively. The type of seizures could not be classified in 6%. In conclusion, the 3.1% prevalence of epilepsy in Danish Labrador Retrievers is higher than the 1% prevalence of epilepsy described in the general canine population, establishing that this breed is at increased risk.

Age Factors↗