Which bone mass measures discriminate adolescents who have fractured from those who have not?

This study of 415 adolescent children examined the association between four different measures of bone mass and prevalent fracture (N = 160 children). DXA measures and calcaneal ultrasound (but not radial ultrasound or metacarpal index) were associated with upper limb fracture, suggesting heel ultrasound is also a discriminator of fractures in children.

INTRODUCTION

The aim of the study was to describe the association between different measures of bone mass and prevalent fracture in adolescents.

METHODS

A total of 415 adolescents (150 girls and 265 boys), mean age 16.3 years were examined. Dual energy X-ray absorptiometry (DXA) measures were performed at hip, spine, radius and total body. Calcaneal bone ultrasound attenuation (BUA), speed of sound (SOS), and stiffness were assessed by a Sahara densitometer. Radial ultrasound SOS was assessed by a Sunlight 8000P machine. Metacarpal index was calculated from a left hand X-ray. Prevalent fractures were assessed by questionnaire.

RESULTS

A total of 160 adolescents (39%) reported at least one previous fracture (106 upper limb, 53 lower limb, one other for first fracture). Significantly lower DXA measures, heel BUA, and heel stiffness was observed in those with a history of upper limb fracture (all P < 0.05). Despite significant correlations between all the bone mass measures, radial ultrasound and metacarpal index did not discriminate those with fracture from those without. Similar associations were present for number of fractures. No bone measure was able to discriminate lower limb fracture.

CONCLUSIONS

Both calcaneal quantitative ultrasound and DXA are able to discriminate adolescents with a history of upper limb fracture from those without.

Cell therapy in models for temporal lobe epilepsy

For patients with refractory epilepsy it is important to search for alternative treatments. One of these potential treatments could be introducing new cells or modulating endogenous neurogenesis to reconstruct damaged epileptic circuits or to bring neurotransmitter function back into balance. In this review the scientific basis of these cell therapy strategies is discussed and the results are critically evaluated. Research on cell transplantation strategies has mainly been performed in animal models for temporal lobe epilepsy, in which seizure foci or seizure propagation pathways are targeted. Promising results have been obtained, although there remains a lot of debate about the relevance of the animal models, the appropriate target for transplantation, the suitable cell source and the proper time point for transplantation. From the presented studies it should be evident that transplanted cells can survive and sometimes even integrate in an epileptic brain and in a brain that is subjected to epileptogenic interventions. There is evidence that transplanted cells can partially restore damaged structures and/or release substances that modulate existent or induced hyperexcitability. Even though several studies show encouraging results, more studies need to be done in animal models with spontaneous seizures in order to have a better comparison to the human situation.

Serial day rapid kindling is an effective tool in screening the anti-epileptic properties of topiramate

INTRODUCTION

In this study, a serial day rapid kindling protocol was used to fully kindle rats in a matter of days. Subsequently, the anticonvulsant profile of a relatively new anti-epileptic drug, topiramate, was evaluated in a cross-over design to further validate this rapid kindling model.

METHODS

Rats were kindled during three consecutive days, according to the serial day rapid kindling protocol. Topiramate was tested at a dose of 100mg/kg, i.p., over the next 2 days using a cross-over design. The stability of the kindled state was evaluated in all rats during two retest paradigms. During the drug-testing procedure, rats received a single i.p. injection of either topiramate or verhicle. Starting 1 h later the rats received additional kindling stimulations during which their response was measured.

RESULTS

Serial day rapid kindling induced a long lasting and stable fully kindled state that allowed for the anti-epileptic drug screening procedure. Topiramate reduced both the afterdischarge duration and ameliorated seizure semiology in the kindled rats.

DISCUSSION

Serial day rapid kindling provided a tool to rapidly kindle rats in 3 days. Using a cross-over design, clear indications on anti-epileptic activity of a given drug can be determined using few laboratory animals.

Opinion of Belgian neurologists on antiepileptic drugs: Belgian Study on Epilepsy Treatment (BESET)

OBJECTIVES

To describe the choice of treatment in adult patients with epilepsy in Belgium, to detect the presence or absence of consensus among neurologists in epilepsy treatment, and to analyze the gaps between current guidelines and prescriptions.

MATERIALS AND METHODS

Hundred Belgian neurologists were systematically interviewed between May and June 2003 using a structured questionnaire (modified Rand method).

RESULTS

Initial monotherapy was the preferred treatment strategy. Valproate was the first choice in idiopathic generalized epilepsy (IGE) and carbamazepine in focal epilepsy (FE). The new antiepileptic drugs (AED) were usually recommended in second-line. However, in special treatment situations, they were considered first-line, e.g., lamotrigine in case of women of childbearing age.

CONCLUSIONS

Neurologists reached consensus for most questions on epilepsy treatment. In 2003, monotherapy with valproate and carbamazepine was the common treatment strategy in Belgium, whereas lamotrigine and to a lesser extent levetiracetam, topiramate, and oxcarbazepine were predominantly prescribed in second-line. This is in agreement with the recently published UK epilepsy guidelines but not in agreement, however, with the US guidelines, that for new onset epilepsy, new and old drugs are equally effective. Belgian neurologists, except for some special situations still prefer old drugs as first line.

Neurosurgical aspects of temporal deep brain stimulation for epilepsy

Deep brain stimulation (DBS), which mimics the effect of ablative surgery in movement disorders, is considered by analogy as potentially useful in the epileptic temporal lobe as an alternative to resection. It could be applied to patients in whom resective surgery is less beneficial, e.g. cases without memory impairment or with bilateral hippocampal involvement. In patients who undergo invasive presurgical analysis, the necessary intrahippocampal leads can serve for the application of DBS, provided that they are suited for chronic use. The hippocampus, in which the focus of epilepsy is detected, is stimulated continuously using high-frequency square-wave pulses. The reduction of interictal spike activity during a period of acute stimulation is the criterion for deciding whether the leads will be connected to an internal pulse generator. We are conducting a pilot study, with 16 patients enrolled so far, ten of whom have been followed up for more than one year. Some theoretical considerations are dedicated to hippocampal DBS.

Clinical experience with vagus nerve stimulation and deep brain stimulation in epilepsy

Patients with refractory epilepsy present a particular challenge to new therapies. Vagus nerve stimulation (VNS) for the control of intractable seizures has become available since 1989. VNS is a relatively noninvasive treatment. It reduces seizure frequency by > or =50% in 1/3 of patients; an additional 1/3 of patients experience a worthwhile reduction of seizure frequency between 30 and 50%. In the remaining 1/3 of the patients there is little or no effect. Efficacy has a tendency to improve with longer duration of treatment up to 18 months postoperatively. Deep brain stimulation (DBS) or direct electrical stimulation of brain areas is an alternative neurostimulation modality. The cerebellum, various thalamic nuclei, the pallidum, and, more recently, medial temporal lobe structures have been chosen as targets. DBS for epilepsy is beyond the stage of proof-of-concept but still needs thorough evaluation in confirmatory pilot studies before it can be offered to larger patient populations. Analysis of larger patient groups and insight in the mode of action may help to identify patients with epileptic seizures or syndromes that respond better either to VNS or to DBS. Randomized and controlled studies in larger patient series are mandatory to identify the potential treatment population and optimal stimulation paradigms. Further improvements of clinical efficacy may result from these studies.

Anatomical and physiological basis and mechanism of action of neurostimulation for epilepsy

Neurostimulation is an emerging treatment for neurological diseases. Different types of neurostimulation exist mainly depending of the part of the nervous system that is being affected and the way this stimulation is being administered. Vagus nerve stimulation (VNS) is a neurophysiological treatment for patients with medically or surgically refractory epilepsy. Over 30,000 patients have been treated with VNS. No clear predictive factors for responders have been identified. To date, the precise mechanism of action remains to be elucidated. Better insight in the mechanism of action may identify seizure types or syndromes that respond better to VNS and may guide the search for optimal stimulation parameters and finally improve clinical efficacy. Deep brain stimulation (DBS) has been used extensively as a treatment for movement disorders. Several new indications such as obsessive compulsive behaviour and cluster headache are being investigated with promising results. The vast progress in biotechnology along with the experience in other neurological diseases in the past ten years has led to a renewed interest in intracerebral stimulation for epilepsy. Epilepsy centers around the world have recently reinitiated trials with deep brain stimulation in different intracerebral structures such as the thalamus, the hippocampus and the subthalamic nucleus.

EFNS guideline on the management of status epilepticus

The objective of the current paper was to review the literature and discuss the degree of evidence for various treatment strategies for status epilepticus (SE) in adults. We searched MEDLINE and EMBASE for relevant literature from 1966 to January 2005. Furthermore, the Cochrane Central Register of Controlled Trials (CENTRAL) was sought. Recommendations are based on this literature and on our judgement of the relevance of the references to the subject. Recommendations were reached by informative consensus approach. Where there was a lack of evidence but consensus was clear we have stated our opinion as good practice points. The preferred treatment pathway for generalised convulsive status epilepticus (GCSE) is intravenous (i.v.) administration of 4 mg of lorazepam or 10 mg of diazepam directly followed by 15-18 mg/kg of phenytoin or equivalent fosphenytoin. If seizures continue for more than 10 min after first injection another 4 mg of lorazepam or 10 mg of diazepam is recommended. Refractory GCSE is treated by anaesthetic doses of midazolam, propofol or barbiturates; the anaesthetics are titrated against an electroencephalogram burst suppression pattern for at least 24 h. The initial therapy of non-convulsive SE depends on the type and the cause. In most cases of absence SE, a small i.v. dose of lorazepam or diazepam will terminate the attack. Complex partial SE is initially treated such as GCSE, however, when refractory further non-anaesthetising substances should be given instead of anaesthetics. In subtle SE i.v. anaesthesia is required.

Memory performance during the intracarotid amobarbital procedure and neuropsychological assessment in medial temporal lobe epilepsy: the limits of material specificity

We investigated the relationship between material-specific memory performance elicited during the Wada test, or intracarotid amobarbital procedure (IAP), and classic neuropsychological assessment in 89 surgical candidates with refractory medial temporal lobe epilepsy (MTLE). The neuropsychological battery included measures of simple and complex verbal and visual memory, whereas the IAP material consisted of verbal and dually encodable stimuli. Neuropsychological testing revealed that reduced verbal memory performance was associated with left-sided MTLE, whereas visual memory tasks revealed no differences between patients with left-sided and right-sided MTLE. During IAP, memory performance was worse with the ipsilesional hemisphere, regardless of lesion side. Most importantly, performance on verbal memory tests was significantly, but moderately, correlated with left hemispheric IAP performance, indicating that memory tasks using verbal material are a valid marker of left hemispheric integrity in left language-dominant MTLE patients and significantly predict left hemispheric memory performance during IAP. In contrast, performance on classic visual memory tests is unrelated to right hemispheric IAP performance, suggesting that the currently used visual memory stimuli do not reflect right hemispheric sensitivity.

Clinical relevance of memory performance during Wada is stimulus type dependent

OBJECTIVES

This study aimed to investigate whether different types of memory stimulus provide different information during the Wada or intracarotid amytal procedure (IAP) in patients with refractory medial temporal lobe epilepsy (MTLE).

METHODS

Eighty nine surgical candidates with documented MTLE and selected for left hemispheric language dominance underwent memory assessment with verbal and dually encodable stimuli during a presurgical IAP.

RESULTS

The overall IAP memory performance with the left hemisphere is significantly better than with the right hemisphere regardless of lesion side. This can be explained by the left hemispheric advantage of encoding all stimuli, whereas the right hemisphere has only limited resources to encode verbal stimuli. More importantly, it appeared that dually encodable items remain more readily recognised following injection ipsilateral to the lesion, whereas verbal items are always better recognised following right hemisphere injection regardless of lesion side.

CONCLUSIONS

Verbal IAP stimuli show left hemispheric sensitivity in left language dominant MTLE patients. The dually encodable items of the IAP appear lesion sensitive.

Language activation distributions revealed by fMRI in post-operative epilepsy patients: differences between left- and right-sided resections

OBJECTIVE

To reveal differences of cerebral activation related to language functions in post-operative temporal lobe epilepsy (TLE) patients.

METHODS

Right (RTL) and left temporal lobe (LTL) resected patients, and healthy controls were studied using functional magnetic resonance imaging (fMRI). Only patients with complete left-hemispheric language dominance according to the intracarotid amytal procedure (IAP) were included. Language-related activations were evoked by performing word generation and text reading language tasks. Activation lateralization and temporo-frontal distribution effects were analysed.

RESULTS

For word generation, only LTL patients showed reduced left lateralized activation compared to controls, due to a decrease in activation in the left prefrontal cortex and an increase in the right prefrontal cortex. For reading, the left-hemispheric lateralization in RTL patients increased because of enhanced activity in the left prefrontal cortex, whereas for LTL patients the activation became bilaterally distributed over the temporal lobes. Lateralization results between pre-operative IAP and post-operative fMRI were highly discordant. Significant temporo-frontal distribution changes manifested from the reading but not from the word generation task.

CONCLUSION

The cerebral language representation in post-operative LTL epilepsy patients is more bi-hemispherically lateralized than in controls and RTL patients. Post-operative temporo-frontal and interhemispheric redistribution effects, involving contralateral homologous brain areas, are suggested to contribute to the cerebral reorganisation of language function.

Vagus nerve stimulation does not affect spatial memory in fast rats, but has both anti-convulsive and pro-convulsive effects on amygdala-kindled seizures

Vagus nerve stimulation (VNS) is an adjunctive treatment for refractory epilepsy. Using a seizure-prone Fast-kindling rat strain with known comorbid behavioral features, we investigated the effects of VNS on spatial memory, epileptogenesis, kindled seizures and body weight. Electrodes were implanted in both amygdalae and around the left vagus nerve of 17 rats. Following recovery, rats were tested in the Morris water-maze utilizing a fixed platform paradigm. The VNS group received 2 h of stimulation prior to entering the Morris water-maze. Rats were then tested in the kindling paradigm wherein the VNS group received 2 h of stimulation prior to daily kindling stimulation. Finally, the abortive effects of acute VNS against kindling-induced seizures were determined in fully kindled rats by applying VNS immediately after the kindling pulse. Body weight, water consumption and food intake were measured throughout. Memory performance in the Morris water-maze was not different between control and vagus nerve stimulation rats. Similarly, kindling rate was unaffected by antecedent VNS. However, pro-convulsive effects (P<0.05) were noted, when VNS was administered prior to the kindling pulse in fully kindled rats. Yet, paradoxically, VNS showed anti-convulsant effects (P<0.01) in those rats when applied immediately after the kindling stimulus. Body weight was significantly lower throughout kindling (P<0.01) in VNS-treated rats compared with controls, which was associated with reduced food intake (P<0.05), but without difference in water consumption. VNS appears to be devoid of significant cognitive side effects in the Morris water-maze in Fast rats. Although VNS exhibited no prophylactic effect on epileptogenesis or seizure severity when applied prior to the kindling stimulus, it showed significant anti-convulsant effects in fully kindled rats when applied after seizure initiation. Lastly, VNS prevented the weight gain associated with kindling through reduced food intake.

Subacute Hashimoto's encephalopathy, treated with plasmapheresis

We report a patient with subacute diffuse encephalopathy characterised by rapidly progressive dementia with visual hallucinations, myoclonus and generalised seizures. She was euthyroid but showed high serum levels of thyreoglobulin and thyreoperoxidase antibodies. Hashimoto's encephalopathy was diagnosed. MRI of the brain in the acute phase demonstrated no structural abnormalities. However in the mesotemporal regions and the anterior parts of the brain, a decrease of the N-acetylaspartate and an increase of the Choline-containing compounds was found on MRI-spectroscopy. Reversal of these abnormalities was demonstrated a few months later after starting therapy. Plasmapheresis resulted in normalisation of serum levels of the antibodies and rapid clinical improvement. This observation supports the idea that a correlation exists between the serum levels of the thyroid auto-antibodies and the course of the clinical illness.

Usefulness of language and memory testing during intracarotid amobarbital testing: observations from an fMRI study

BACKGROUND

Several procedures for testing language lateralization and memory function exist during the intracarotid amobarbital test (IAT). The use of functional magnetic resonance imaging (fMRI) gives the opportunity to assess the validity of some of these procedures, or at least to inspect the neuronal correlates. A comprehensive fMRI protocol was tested, aimed at addressing aspects of lateralization of language, as well as testing memory in relation to activation of mesiotemporal regions. Here we report observations with possible consequences for the current IAT procedures.

MATERIALS AND METHODS

The protocol consisted of three language tasks (overt naming, semantic decision and silent word generation) and two memory tasks (encoding and retrieving visual scenes). The paradigms used a block-related procedure in nine right-handed normal volunteers. During the procedure dynamic weighted full brain images were acquired which are sensitive to the blood oxygenation activation effect.

RESULTS

Encoding showed symmetrical bilateral activation in the mesiotemporal regions, specifically the hippocampus, parahippocampal gyrus and fusiform gyrus. With a retrieval task activation of the mesiotemporal areas was restricted to the posterior hippocampal area. Overt object naming showed results, similar to encoding tasks with bilateral activation of hippocampal areas. Silent word generation showed much stronger ability to lateralize than the other two language-related tasks and especially object naming.

CONCLUSION

Activation revealed by fMRI activation shows that IAT procedures, using active semantic language processing or comprehensive procedures with multiple language tasks have the highest guarantee for individual activation lateralization. Simple object naming does not guarantee a lateralized language fMRI activation pattern. Of the different memory procedures during IAT, the procedures (Interview and the Montreal) demanding encoding processing will be related to larger areas of bilateral hippocampal activation than procedures (Seattle) exclusively requiring retrieval. Moreover, tasks using recognition of previously presented language items (naming objects) are equally effective for assessing hippocampal activation compared with presenting separate memory items.

The pathophysiology of motor symptoms in Parkinson's disease

This review focuses on some of the known and hypothetical pathophysiological mechanisms underlying the motor symptoms in Parkinson's disease (PD). Current views on these mechanisms have largely been influenced by models of basal ganglia functioning and dysfunctioning. These models have allowed to explain some clinical findings and to predict a number of results of basal ganglia surgery in movement disorders. However, neurophysiological studies as well as neurochemical data have broadened our vision on basal ganglia functioning and dysfunctioning in PD. Moreover, these more fundamental insights in basal ganglia functioning allow new concepts on the development of treatment strategies, and on the prevention of motor fluctuations in PD.

Detection of spike and wave discharges in the cortical EEG of genetic absence epilepsy rats from Strasbourg

Genetic absence epilepsy rats from Strasbourg (GAERS) are a strain of Wistar rats in which all animals present spontaneous occurrence of spike and wave discharges (SWD) in the cortical electroencephalogram (EEG). In this paper, we present a method for the detection of SWD, based on the key observation that SWD are quasi-periodic signals. A spectral-comb based analysis method is used to extract the fundamental frequency and the percentage of energy explained by the harmonic spectral components is subsequently used as a detection parameter. It is shown that a maximum sensitivity and specificity of up to 96 per cent can be achieved. We also compared the performance of this method with the methods presented in the literature and conclude that the surplus value of the novel detection method lies in the higher specificity that can be obtained in the analysis of long-term EEG fragments, which are contaminated by artefacts and contain large portions of slow-wave sleep.

Magnetic source imaging contributes to the presurgical identification of sensorimotor cortex in patients with frontal lobe epilepsy

OBJECTIVE

One of the primary goals of preoperative evaluation of patients considered to be candidates for epilepsy surgery is the delineation of eloquent cortex adjacent to the area of resection. The aim of this study is the functional localization of the sensorimotor cortex in relation to an epileptogenic frontal lobe lesion, thus enabling a more complete resection in these patients while minimizing the risk of postoperative neurological deficits.

METHODS

Participating in this study were patients with epilepsy, diagnosed as being related to a left or right frontal lobe lesion. Magnetoencephalographic responses evoked by electrical stimulation of the left and right hand median nerve were localized using single time-point equivalent dipole (ED) modeling, taking into account the realistic shape of the head. Instead of relying on the primary component (N/P 20) of the somatosensory evoked magnetic fields (SEFs) in this study ED fits were obtained for each time-point of the somatosensory evoked responses. On a cortical rendering, the reconstructed dipoles were depicted relative to the anatomy obtained from 3D-magnetic resonance imaging.

RESULTS

The results of single time-point ED analysis including all the components of the responses indicated that the sources underlying the SEFs are located at the borders of the central sulcus (CS). The opposite direction of the sources underlying, respectively, the primary and subsequent late component of the SEFs indicated distinct sources located at the opposite banks of the CS. These sources, therefore, might correspond to the sensory hand projection area and the primary motor area of the sensorimotor cortex. It appeared that the location of the EDs obtained for the SEFs of 4 of the 7 patients studied were asymmetric for the left and right hemisphere, probably because of a displacement of the sensorimotor areas relative to the CS. The systematic assessment of the dipole fits compared to brain anatomy confirmed that volume conduction changes due to the lesion were not responsible for these observed deviations, thus leaving as explanation space-occupying and neurophysiological changes due to the lesion.

Vagus nerve stimulation for epilepsy, clinical efficacy of programmed and magnet stimulation

RATIONALE

Vagus nerve stimulation (VNS) by intermittent and programmed electrical stimulation of the left vagus nerve in the neck, has become widely available. It is an effective treatment for patients with refractory epilepsy. Patients can be provided with a magnet that allows to deliver additional stimulation trains. Since earlier studies have demonstrated the persistence of a stimulation effect after discontinuation of the stimulation train, we evaluated the clinical efficacy of VNS both in the programmed intermittent stimulation mode and magnet stimulation mode.

METHODS

A group of 30 patients (16 F, 14 M) with medically refractory partial epilepsy, who were unsuitable candidates for resective surgery, were included in the study. The patients, their companions and caregivers were instructed on how to administer additional stimulation trains using a hand-held magnet when an aura or a seizure onset occurred. Patients or caregivers could recognize habitual seizures and were able to evaluate sudden interruption of these seizures. Using seizure diaries, detailed accounts of magnet use and regular clinic follow-up visits, data on seizure frequency and severity and number of magnet applications were collected. Patients who provided unreliable information were excluded from the analysis.

RESULTS

Forty-seven percent of all patients had an improvement in seizure control with a reduction in seizure frequency of more than 50% during a mean follow-up of 33 months (range: 4-67 months). More than half of the patients used the magnet and provided reliable information. In 63% of patients who were able to self-administer or receive additional magnet stimulation, seizures could be interrupted, be it consistently or occasionally. More than half of the patients who reported a positive effect of magnet stimulation became responders. In most cases the magnet was applied by a caregiver.

CONCLUSIONS

To our knowledge, this study is the first to explore the efficacy of magnet-induced vagus nerve stimulation. Results suggest that the magnet is a useful tool that provides patients and mainly caregivers with an additional means of controlling refractory seizures. Additional controlled studies comparing programmed stimulation and magnet-induced stimulation in monitoring conditions are warranted.

Developing a comprehensive presurgical functional MRI protocol for patients with intractable temporal lobe epilepsy: a pilot study

Our aim was to put together and test a comprehensive functional MRI (fMRI) protocol which could compete with the intracarotid amytal (IAT) or Wada test for the localisation of language and memory function in patients with intractable temporal lobe epilepsy. The protocol was designed to be performed in under 1 h on a standard 1.5 tesla imager. We used five paradigms to test nine healthy right-handed subjects: complex scene-encoding, picture-naming, reading, word-generation and semantic-decision tasks. The combination of these tasks generated two activation maps related to memory in the mesial temporal lobes, and three language-related maps of activation in a major part of the known language network. The functional maps from the encoding and naming tasks showed typical and symmetrical posterior mesial temporal lobe activation related to memory in all subjects. Only four of nine subjects also showed symmetrical anterior hippocampal activation. Language lateralisation was best with the word generation and reading paradigms and proved possible in all subjects. The reading paradigm enables localisation of language function in the left anterior temporal pole and middle temporal gyrus, areas typically resected during epilepsy surgery. The combined results of this comprehensive f MRI protocol are adequate for a comparative study with the IAT in patients with epilepsy being assessed for surgery.