Biomedical subjects

Ivan Rektor

Publications and source records attributed to Ivan Rektor.

At least 19 recordsLinked to original sources

PubMed2006

fMRI evaluation of hemispheric language dominance using various methods of laterality index calculation.

Several functional MR imaging studies evaluating the lateralisation of linguistic functions in patients who underwent Wada testing have been reported. There is extensive variance in the Laterality index (LI) calculation across the studies, and the optimal calculation method remains unclear. We attempted to calculate the LI in different ways in the same subjects, in order to find the LI calculation method with the highest correlation to the Wada test. Fifteen patients (10 females, 5 males) suffering from medically intractable temporal lobe epilepsy (TLE) (12 left, 3 right) were admitted for the study. The patients underwent a standardized bilateral intracarotid short-acting barbiturate test. Language testing included spontaneous speech, oral comprehension, reading, object and picture naming, and repetition. All the tasks were scored separately in order to increase the possibility of correlation between Wada and LI. A silent phonemic verbal fluency task (VFT) was used as a language paradigm for functional measurement. Regions of interest (ROIs), with a known association with language function (Broca's area, the lateral prefrontal cortex, etc.), were defined. First, the LIs were calculated from the ROIs using a previously reported method (simple suprathreshold count). Next, we used several new methods of LI calculation (t-weighting of voxels, methods independent of the choice of the statistical threshold, etc.) The most significant correlation with Wada was proven in the LIs that were evaluated from Broca's area (up to R = 0.94, P = 1 x 10(-7)). However, the new LI calculation methods used in the present study did not produce a statistically significant benefit in comparison to previously reported methods.

Adult↗

PubMed2006

The effect of response type (motor output versus mental counting) on the intracerebral distribution of the slow cortical potentials in an externally cued (CNV) paradigm.

OBJECTIVE: Previous surface CNV studies including a hand motor output have suggested that the late phase of the CNV reflects the preparation of the sensorimotor cortices involved in the motor output given the same similarity in scalp potential distribution with readiness potential. However, the poor spatial resolution of the scalp recorded CNV data prevented a definitive conclusion. This intracerebral study allowed us to test this hypothesis using a CNV paradigm in which a non-motor task is used as a reference. This study concerned the intracerebrally located generators of the Contingent Negative Variation in two different paradigm settings: (i) motor output required, (ii) silent counting required (non-motor control condition). METHODS: Stereoelectroencephalography (SEEG) recordings of the contingent negative variation (CNV) in a somato-somatosensory stimulation paradigm with a motor or counting task were taken from nine patients with drug-resistant epilepsy. The intracerebral recordings were taken from 25 cortical areas in both hemispheres (supplementary motor area-SMA; the cingulate gyrus; the orbitofrontal, premotor and dorsolateral prefrontal cortices; lateral temporal cortex, amygdalohippocampal complex; and the parietooccipital cortex). RESULTS: The slow waves were generated in the SMA, the premotor, dorsolateral, and orbitofrontal cortices, the cingulate gyrus, and parts of the lateral temporal, mesial temporal structures and parietal cortex. We found a significant difference between the two tasks in the CNV potential generation. The task with the motor output produced significantly higher numbers of CNV potential generators when compared to the task with silent counting. CONCLUSIONS: The CNV potential generators varied between motor and non-motor tasks. The intracerebral distribution of the potentials linked with expectation is task dependent. Our main conclusion is that the executive network is more active during the motor task than during counting task.

Adolescent↗

PubMed2006

Vascular parkinsonism--an update.

Vascular parkinsonism (VP) is a heterogeneous clinical entity. The idea of a relationship between cerebral vascular disease and parkinsonism may be traced back to the 1920s, when the diagnostic unit called "arteriosclerotic parkinsonism", a predecessor of VP, was established. This review is concerned with historical and contemporary views regarding the possible vascular genesis of parkinsonism. Confusion persists as a result of vaguely defined diagnostic criteria. The following types of simultaneous occurrence of parkinsonism and cerebral vascular disease (CVD) may be recognised: 1. gait disorders of the lower body parkinsonism type are caused mostly by white matter lesions in the frontal lobes; such disorders may require a diagnosis of vascular origin. We suggest replacing the term "lower body parkinsonism" with a more appropriate term not including the word "parkinsonism": an alternative term could be "cerebrovascular gait disorder"; 2. if the signs and symptoms are typical for idiopathic Parkinson's disease (IPD), the coincidence of IPD and CVD should be considered; 3. if the symptoms of parkinsonism are neither typical for IPD nor for VP, and there are clinical or MR signs of CVD, VP should be regarded as possible when alternative causes are excluded; 4. if the symptoms of parkinsonism and clinical and MR signs are typical for VP, VP should be regarded as probable; 5. if a stroke affecting the contralateral basal ganglia is followed by the occurrence of hemiparkinsonism, the diagnosis of VP is unambiguous. Vascular parkinsonism (VP) is probably one of the most frequently erroneous neurological diagnoses. The reason for this misdiagnosis is that both cerebral vascular disease (CVD) and parkinsonism usually occur at the same age. Due to the high incidence of CVD, it is possible for CVD and idiopathic Parkinson's disease (IPD) to coincide in some cases. Another reason for the misdiagnosis is that the concept of VP lacks clarity. This review aims to contribute to an improved understanding of VP in clinical practice. In this context, the term "CVD" is understood in the broad sense of a brain impairment caused by cerebral vessel pathology. It covers various concepts, as some authors use the term CVD to mean a manifestation of vascular lesions in pathologico-anatomical material or in the imaging techniques; others mean the history and clinical manifestation of cerebral ischaemia, or, more rarely, haemorrhage. The term CVD may cover large vessel disease as well as small vessel disease. This means that territorial and lacunar infarcts and white matter lesions (WML) are all considered as CVD.

Cerebrovascular Disorders↗

PubMed2006

Magnetic resonance spectroscopy of the thalamus in patients with typical absence epilepsy.

PURPOSE: To investigate possible neuronal dysfunction of the thalamus in patients suffering from typical absence epilepsy, using magnetic resonance spectroscopy (MRS). Special attention was paid to levels of N-acetylaspartate (NAA) and creatine (Cr), and to the NAA/Cr ratio. METHODS: MRS was performed over the right and left thalamus in nine patients suffering from typical absence epilepsy, and in nine sex- and age-matched healthy controls. All patients and controls were examined using a standard MRS-CSI (chemical shift imaging) technique. RESULTS: Statistical analysis of the obtained data demonstrated a significantly lower thalamic NAA/Cr ratio in patients with typical absence epilepsy when compared to the healthy controls. Our MRS data showed symmetrical distribution of NAA/Cr ratio in the right and left thalamus within both the patient group and the group of healthy controls. No significant correlation between the patients' thalamic NAA/Cr values and the duration of the epilepsy or seizure frequency was revealed. CONCLUSIONS: The present MRS data clearly indicate neuronal dysfunction in the thalami of patients with typical absence epilepsy. In agreement with other recent MRS findings in different idiopathic generalized epilepsy syndromes, our results confirm the role of the thalamus as an important structure in the pathogenesis of typical absence epilepsy.

Adult↗

PubMed2006

Intracerebral recording of cortical activity related to self-paced voluntary movements: a Bereitschaftspotential and event-related desynchronization/synchronization. SEEG study.

To analyze the distribution of the cortical electrical activity related to self-paced voluntary movements, i.e. the movement-related readiness potentials (Bereitschaftspotential, BP) and the event-related desynchronization (ERD) and synchronization (ERS) of cortical rhythms using intracerebral recordings. EEG was recorded in 14 epilepsy surgery candidates during preoperative video-stereo-EEG monitoring. Subjects performed self-paced hand movements, with their right and left fingers in succession. EEG signals were obtained from a total of 501 contacts using depth electrodes located in primary and nonprimary cortical regions. In accordance with previous studies, BP was found consistently in the primary motor (M1) and somatosensory (S1) cortex, the supplementary motor area (SMA), and in a few recordings also in the cingulate cortex and in the dorsolateral prefrontal and premotor cortex. ERD and ERS of alpha and beta rhythms were also observed in these cortical regions. The distribution of contacts showing ERD or ERS was larger than the distribution of those showing BP. In contrast to BP, ERD and ERS frequently occurred in the lateral and mesial temporal cortex and the inferior parietal lobule. The number of contacts and cortical regions showing ERD and ERS and not BP suggests that the two electrophysiological phenomena are differently involved in the preparation and execution of simple voluntary movements. Substantial differences between BP and ERD in spatial distribution and the widespread topography of ERD/ERS in temporal and higher-order motor regions suggest that oscillatory cortical changes are coupled with cognitive processes supporting movement tasks, such as memory, time interval estimation, and attention.

Adolescent↗

PubMed2006

Sexual dysfunctions and blood hormonal profile in men with focal epilepsy.

PURPOSE: To evaluate the incidence of sexual dysfunction in men with focal epilepsy and to establish their hormonal profiles. METHODS: We prospectively analyzed sexual functions and hormone blood levels in 40 male patients (age ranged from 18 to 44 years, with an average age of 27.6+/-5.6 years) with refractory focal epilepsy. We used the Czech version of the structured questionnaire entitled International Inventory of Erectile Function (IIEF) to assess the patients' sexual functions. The subscales of this questionnaire separately evaluate erectile function (IIEF I), orgasmic function (IIEF II), sexual desire (IIEF III), intercourse satisfaction (IIEF IV), and overall satisfaction with sex life (IIEF V). In all of the patients, the following blood tests were performed: quantitative assessment of blood levels of prolactin (PRL), total testosterone (total-T), free androgen index (FAI), sexual hormone-binding globulin (SHBG), estradiol (E2), dehydroepiandrosterone sulfate (DHEAS), progesterone (PRG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH). All these quantitative laboratory data were correlated with other clinical variables and with the results of the IIEF. chi2 and Wilcoxon tests were used for the statistical analysis. A p-value<0.05 was considered to be statistically significant. RESULTS: At least one of the types of sexual dysfunction, as defined by IIEF (IIEF I, II, and III), was found in 22 (55%) of the 40 patients (55%). Erectile dysfunction (IIEF I) was found in six (15%) of 40 patients, orgasmic dysfunction (IIEF II) in six (15%) of 40 patients, and loss of sexual desire (IIEF III) in 16 (40%) of 40 patients. According to other subscales of IIEF, 22 (55%) of 40 patients were not satisfied with sexual intercourse (IIEF IV), and 20 (50%) of 40 patients were not satisfied with their sex livee (IIEF V). None of the subscales of IIEF was significantly correlated with the age of the patients or with the duration of epilepsy. In patients with at least one of the sexual dysfunctions (IIEF I, II, and III), we found a statistically significant increase of FSH and SHBG, and a decrease of DHEAS and FAI in comparison with those in the patients with normal sexual functions. In patients with erectile dysfunction, we found the same changes and a significant increase of E2. In patients with orgasmic dysfunction, we found a statistically significant decrease of DHEAS. In patients with dysfunction of sexual desire, we noticed a significant increase of SHBG and a decrease of DHEAS and FAI. All patients with orgasmic dysfunction were being treated with carbamazepine (CBZ) in monotherapy or combination therapy. In patients with at least one type of sexual dysfunction (IIEF I, II, and III), we found a higher proportion of valproate treatment in monotherapy or combination therapy in comparison with CBZ. CONCLUSIONS: Our study showed a relatively high incidence of sexual dysfunction and dissatisfaction with sexual intercourse and sex life, as defined by the IIEF I-V questionnaire, in men with refractory focal epilepsy. The most frequent dysfunction in these patients is the impairment of sexual desire. However, our study indicates some specific hormonal changes related to various types of sexual dysfunction that are not related to antiepileptic drug treatment.

Adolescent↗

PubMed2006

Combining advanced neuroimaging techniques in presurgical workup of non-lesional intractable epilepsy.

PURPOSE: The rationale for this case report is to assess the degree of congruency between the results of several advanced functional, metabolic, and structural neuroimaging techniques used in patients with MRI-negative focal epilepsy. METHODS: We investigated the presurgical evaluation and post-operative outcome of a patient with intractable, extratemporal epilepsy. Because the habitual seizures in this patient could be easily induced, six, advanced, neurodiagnostic techniques were successively applied (SISCOM, ictal FDG-PET, ictal fMRI, postictal diffusion-weighted imaging, voxel-based morphometry, and MRS imaging). RESULTS: The findings for the neuroimaging methods investigated, within the left central region, were fairly congruent. Subsequent, invasive EEG recordings revealed a seizure-onset zone at the site where most of the neuroimaging had shown abnormal findings. The surgical removal of the epileptogenic zone, as defined by concordant neuroimaging and SEEG data, resulted in seizure-free postoperative outcome. Histopathological findings revealed mild focal cortical dysplasia. CONCLUSION: Great efforts should be made to combine most of the advanced neuroimaging methods in the preoperative assessment of non-lesional epilepsy surgery candidates.

Adult↗

PubMed2005

Prophylaxis of thrombotic and embolic events in acute ischemic stroke with the low-molecular-weight heparin certoparin: results of the PROTECT Trial.

BACKGROUND AND PURPOSE: Patients with stroke are at substantial risk of thromboembolic complications and therefore require antithrombotic prophylaxis. To show the noninferiority of the low-molecular-weight heparin certoparin to unfractionated heparin (UFH) for the prevention of thromboembolic complications, we performed a randomized, double-blind, active-controlled multicenter trial in patients with acute ischemic stroke. METHODS: Overall, 545 patients were randomized within 24 hours of stroke onset to treatment with certoparin (3000 U anti-Xa OD; n=272) or UFH (5000 U TID; n=273) for 12 to 16 days. Patients with paresis of a leg and an National Institutes of Health Stroke Scale score of 4 to 30 points were included. The primary end point was a composite outcome of proximal deep vein thrombosis, pulmonary embolism, or death related to venous thromboembolism during treatment. Computed tomography was performed at trial entry, after 7 days, and when clinical deterioration occurred. RESULTS: The per-protocol analysis revealed 17 (7.0%) primary events in the certoparin group compared with 24 (9.7%) in the UFH group, thereby demonstrating noninferiority (P=0.0011), confirmed by intention-to-treat analysis (6.6% versus 8.8%; P=0.008). Major bleeding occurred during treatment in 3 patients allocated to certoparin (1.1%) and 5 patients allocated to UFH (1.8%). CONCLUSIONS: Certoparin (3000 U anti-Xa OD) is at least as effective and safe as UFH (TID) for the prevention of thromboembolic complications in patients with acute ischemic stroke.

Adolescent↗

PubMed2005

The long-lasting improvement of sexual dysfunction in patients with advanced, fluctuating Parkinson's disease induced by pergolide: evidence from the results of an open, prospective, one-year trial.

Fourteen male patients suffering from Parkinson's disease, each of whom had been treated with L-DOPA, and in whom additional treatment with oral dopamine agonist (DA) was needed, were followed for a period of one year. Pergolide mesylate (Permax) was given to each patient, and titrated to a total daily dose of 3 mg. All of the patients were taking L-DOPA. The assessments performed before the start of pergolide treatment consisted of neurological examination, unified Parkinson's disease rating scale (UPDRS) III and IV subscales scoring, mini mental state examination (MMSE) scoring, the neuropsychological examination including Zung scale scoring, biochemical and hematological examinations including prolactine serum levels; and a sexological examination during which the patients filled-in the international index of erectile function (IIEF) questionnaire. These examinations were repeated during the control assessments at months 1, 3, 6 and 12. ANOVA, non-parametric Friedmann's ANOVA and Tukey post hoc tests were used for the statistical analysis. There were statistically significant differences between the values of UPDRS III motor subscale and all subscales of IIEF when months 0 and 1 were compared with the results obtained at months 3, 6 and 12. Pergolide mesylate, when added to L-DOPA, significantly improved all sexual functions in younger male Parkinsonian patients who were still interested in sexual activities. The treatment with pergolide in these cases might be more beneficial than with short-acting PDE-5 inhibitor sildenafile. Nevertheless, the relationship between pergolide treatment and incidence of restrictive valvular heart disease must be considered.

Aged↗

PubMed2005

Combined event-related fMRI and intracerebral ERP study of an auditory oddball task.

Event-related fMRI (efMRI) has been repeatedly used to seek the neural sources of endogenous event-related potentials (ERP). However, significant discrepancies exist between the efMRI data and the results of previously published intracranial ERP studies of oddball task. To evaluate the capacity of efMRI to define the sources of the P3 component of ERP within the human brain, both efMRI and intracerebral ERP recordings were performed in eight patients with intractable epilepsy (five males and three females) during their preoperative invasive video-EEG monitoring. An identical auditory oddball task with frequent and target stimuli was completed in two sessions. A total of 606 intracerebral sites were electrophysiologically investigated by means of depth electrodes. In accordance with the finding of multiple intracerebral generators of P3 potential, the target stimuli evoked MRI signal increase in multiple brain regions. However, regions with evident hemodynamic and electrophysiological responses overlapped only partially. P3 generators were always found within hemodynamic-active sites, if these sites were investigated by means of depth electrodes. On the other hand, unequivocal local sources of P3 potential were apparently also located outside the regions with a significant hemodynamic response (typically in mesiotemporal regions). Both methods should thus be viewed as mutually complementary in investigations of the spatial distribution of cortical and subcortical activation during oddball task.

Adult↗

PubMed2005

Cognitive- and movement-related potentials recorded in the human basal ganglia.

Sources of potentials evoked by cognitive processing of sensory and motor activities were studied in 9 epilepsy surgery candidates with electrodes implanted in the basal ganglia (BG), mostly in the putamen. Several contacts were also located in the pallidum and the caudate. The recorded potentials were related to a variety of cognitive and motor activities (attentional, decisional, time estimation, sensory processing, motor preparation, and so on). In five different tests, we recorded P3-like potentials evoked by auditory and visual stimuli and sustained potential shifts in the Bereitschaftspotential and Contingent Negative Variation protocols. All of the studied potentials were generated in the BG. They were recorded from all over the putamen. Various potentials on the same lead or nearby contacts were recorded. A functional topography in the BG was not displayed. We presume that the cognitive processes we studied were produced in clusters of neurons that are organized in the basal ganglia differently than the known functional organization, e.g., of motor functions. The basal ganglia, specifically the striatum, may play an integrative role in cognitive information processing, in motor as well as in nonmotor tasks. This role seems to be nonspecific in terms of stimulus modality and in terms of the cognitive context of the task.

Adult↗

PubMed2005

Intracerebral P3-like waveforms and the length of the stimulus-response interval in a visual oddball paradigm.

OBJECTIVE: This study investigated the possible linkage of intracerebrally recorded P3-like waveforms to the processes induced by stimulus perception or motor response formation. METHODS: Event-related potentials were recorded from 560 cerebral sites in 17 patients suffering from intractable epilepsy during visual oddball task. Potentials evoked by the target stimuli were sorted according to button-pressing response times, and the P3 waveform was analyzed both in stimulus-locked and response-locked averages, which were separately averaged for fast and slow responses. RESULTS: P3-like waveforms were identified in 180 sites in 17 patients. Three different types of P3-like waveforms, diffusely distributed within the brain, were found: (1) time-locked to the stimulus (30 sites in 11 patients); (2) time-locked to the motor response (52 sites in 13 patients); and (3) with ambiguous time relationship to stimulus and motor response (98 sites in 16 patients). CONCLUSIONS: The intracerebral P3-like waveform could represent different processes involved in performing active oddball tasks. Therefore, our results support the hypothesis that the P3 waveform registered by surface electrodes could be a heterogeneous phenomenon. SIGNIFICANCE: These results provide evidence that the P3 waveform is not only related to stimulus processing, which differs from what has been generally claimed in the literature.

Adult↗

PubMed2005

Dropped head syndrome in severe intractable epilepsies with mental retardation.

PURPOSE: Dropped head syndrome is characterized by a gradual forward sagging of the head due to the isolated weakness of the neck extensor muscles. The syndrome has a relatively benign clinical course. To date, there have been no reports of dropped head syndrome in epileptic patients. METHODS: Nine patients with intractable epilepsy (mean age, 33.6+/-9.91 years), each presenting with apparent dropped head, were evaluated. The duration of the drooping head symptom varied from 3 to 15 years (mean, 7.4+/-4.06 years), with a slowly progressing weakness in most of the patients. In all of the patients, extensive clinical, laboratory, electrophysiological, histopathological, and neuroimaging examinations were performed. RESULTS: The weakness in all of the subjects was strictly limited to the cervical paraspinal muscles. Laboratory studies produced normal results from all subjects. EMG and muscle biopsy were normal or revealed subtle nonspecific myopathic changes without inflammation in the cervical paraspinal muscles. Polymyographic investigation revealed that none of the patients had convincing dystonic spasms of the anterior neck muscles. No atrophy or fatty changes of the neck extensor muscles were observed on CT or MRI. In most of the patients (7/9), altered L-carnitine concentrations were observed (four patients displayed a marked decrease in plasma carnitine concentrations, and three other patients showed abnormalities in urinary excretion of carnitine). CONCLUSIONS: These findings seem to suggest that a secondary carnitine deficiency, induced by antiepileptic drugs (principally valproic acid), represents a plausible pathogenetic mechanism for the development of dropped head in some epileptic patients.

Adult↗

PubMed2004

Cognitive potentials in the basal ganglia-frontocortical circuits. An intracerebral recording study.

We studied cognitive functions related to processing sensory and motor activities in the basal ganglia (BG), specifically in the putamen and in cortical structures forming the BG-frontocortical circuits. Intracerebral recordings were made from 160 brain sites in 32 epilepsy surgery candidates. We studied P3-like potentials in five different tests evoked by auditory and visual stimuli, and two sustained potentials that are related to cognitive activities linked with movement preparation: BP (Bereitschaftspotential) and CNV (contingent negative variation). We compared the presence of a potential with a phase reversal or an amplitude gradient to the absence of a generator. All of the studied cognitive potentials were generated in the BG; the occurrence in frontal cortical areas was more selective. The frequency of all but one potential was significantly higher in the BG than in the prefrontal and in the cingulate cortices. The P3-like potentials elicited in the oddball paradigm were also more frequent in the BG than in the motor/premotor cortex, while the occurrence of potentials elicited in motor tasks (BP, CNV, and P3-like potentials in the CNV paradigm) in the motor cortex did not significantly differ from the occurrence in the BG. The processing of motor tasks fits with the model by Alexander et al. of segregated information processing in the motor loop. A variable and task-dependent internal organisation is more probable in cognitive sensory information processing. Cognitive potentials were recorded from all over the putamen. The BG may play an integrative role in cognitive information processing.

Acoustic Stimulation↗

PubMed2004

How to treat tremor.

This paper presents an example of 18(th) century medical thinking. The author, Dr Georg Ernst Stahl (1659-1734) was the founder of the phlogiston theory in the field of chemistry, a medical professor, and a court physician in Saxony and Prussia. His description includes a definition of tremor, the internal and external causes of tremor, the types of tremor, the diagnostic and prognostic signs, and the treatment. From a present (contemporary) point of view, some compounds that were then used in treatment may have had a limited therapeutic effect on some kinds of tremor. Protopin has an anticholinergic and GABA-ergic effect, and rhoeadin (tetrahydrobenzazepin) may have had an effect similar to that of neuroleptics. Nevertheless, it is not clear whether the recommended quantity of these compounds was sufficient for a clinical effect. Most of the prescribed drugs could only have had a placebo effect.

Benzophenanthridines↗

PubMed2004

Complete loss of the cytoplasmic carboxyl terminus of the KCNQ2 potassium channel: a novel mutation in a large Czech pedigree with benign neonatal convulsions or other epileptic phenotypes.

PURPOSE: Benign neonatal familial convulsions (BNFCs) represent a rare epileptic disorder with autosomal dominant mode of inheritance. To date, two voltage-gated potassium (K+) channel genes, KCNQ2 and KCNQ3, have been identified in typical BNFC families. The study of new pedigrees may help detect new mutations and define genotype-phenotype correlations. METHODS: A large Czech family was detected in which BNFC was inherited together with a broad range of various nonneonatal epileptic phenotypes. Genetic linkage study and direct mutation analysis were performed to find the disease-causing mutation. RESULTS: In seven patients with BNFCs and no recurrence of seizures, a novel two-base-pair deletion (1369del2) was identified within the coding sequence of the KCNQ2 gene. The mutation led to a putative protein that lacked nearly all its carboxyl terminus part, which plays a critical role for the accurate expression of the functional K+ channels. Three patients with generalized tonic-clonic seizures (GTCSs), all without any history of BNFCs, also displayed 1369del2. Three other patients with other idiopathic epileptic phenotypes did not have the mutation. CONCLUSIONS: A novel 2-bp deletion within the coding sequence of the potassium channel KCNQ2 gene was detected in patients from a large and heterogeneous family with BNFCs or non-BNFC seizures.

Adolescent↗

PubMed2004

Synchronization of gamma oscillations increases functional connectivity of human hippocampus and inferior-middle temporal cortex during repetitive visuomotor events.

Do recency processes associated with repetitive sensorimotor events modulate the magnitude and functional coupling of brain rhythmicity in human temporal cortex? Intracranial stereo electroencephalographic activity (SEEG; 256 Hz sampling rate) was recorded from hippocampus, and inferior (BA20) and middle (BA21) temporal cortex in four epilepsy patients. The repetitive events were represented by predicted imperative somatosensory stimuli (CNV paradigm) triggering hand movements ("repetitive visuomotor") or counting ("repetitive counting"). The non-repetitive events were "rare" (P3 paradigm) somatosensory stimuli triggering hand movements ("non-repetitive visuomotor") or counting ("non-repetitive counting"). Brain rhythmicity was indexed by event-related desynchronization/synchronization (ERD/ERS) of SEEG data, whereas the functional coupling was evaluated by spectral SEEG coherence between pairs of the mentioned areas. The frequency bands of interest were theta (4-8 Hz), alpha (8-12 Hz), beta (14-30 Hz), and gamma (32-46 Hz). Compared to the non-repetitive events, the "repetitive visuomotor" events showed a significant beta and gamma ERS in the hippocampus and a significant theta ERD in the inferior temporal cortex. Furthermore, the "repetitive visuomotor" events induced a task-specific significant gamma coherence among the examined areas. These results suggest that recency processes do modulate the magnitude and functional coupling of brain rhythmicity (especially gamma) in the human temporal cortex.

Adult↗

PubMed2004

Unruptured intracranial aneurysm as a cause of focal epilepsy: an excellent postoperative outcome after intra-arterial treatment.

This report involves a patient suffering from focal epilepsy caused by an unruptured, intracranial aneurysm (UIA), and her treatment using intravascular embolisation, with an excellent postoperative outcome in terms of the epilepsy. A 52 year-old, right-handed woman had been suffering for three years from focal seizures, characterized by loss of consciousness, and oroalimentary and hand automatisms. The epilepsy was not controlled by carbamazepine monotherapy. Magnetic resonance imaging and digital subtraction angiography revealed a saccular aneurysm at the bifurcation of the middle cerebral artery, in contact with the cortex of the temporal opercular region. An intra-arterial embolisation, using a detachable, mechanical spiral (MDS, Bold Platinum), was performed, with no complications. The purpose of embolisation was the treatment of the aneurysm. The patient had two more, complex partial seizures (CPS) in the early postoperative period, but was seizure-free between September 1998 and September 2002. This is the first case report that presents the successful treatment of UIA-related epilepsy by means of intravascular embolisation.

Cerebral Angiography↗