scholarly journals Real-time functional mapping: potential tool for improving language outcome in pediatric epilepsy surgery

2014 ◽  
Vol 14 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Milena Korostenskaja ◽  
Po-Ching Chen ◽  
Christine M. Salinas ◽  
Michael Westerveld ◽  
Peter Brunner ◽  
...  

Accurate language localization expands surgical treatment options for epilepsy patients and reduces the risk of postsurgery language deficits. Electrical cortical stimulation mapping (ESM) is considered to be the clinical gold standard for language localization. While ESM affords clinically valuable results, it can be poorly tolerated by children, requires active participation and compliance, carries a risk of inducing seizures, is highly time consuming, and is labor intensive. Given these limitations, alternative and/or complementary functional localization methods such as analysis of electrocorticographic (ECoG) activity in high gamma frequency band in real time are needed to precisely identify eloquent cortex in children. In this case report, the authors examined 1) the use of real-time functional mapping (RTFM) for language localization in a high gamma frequency band derived from ECoG to guide surgery in an epileptic pediatric patient and 2) the relationship of RTFM mapping results to postsurgical language outcomes. The authors found that RTFM demonstrated relatively high sensitivity (75%) and high specificity (90%) when compared with ESM in a “next-neighbor” analysis. While overlapping with ESM in the superior temporal region, RTFM showed a few other areas of activation related to expressive language function, areas that were eventually resected during the surgery. The authors speculate that this resection may be associated with observed postsurgical expressive language deficits. With additional validation in more subjects, this finding would suggest that surgical planning and associated assessment of the risk/benefit ratio would benefit from information provided by RTFM mapping.

2015 ◽  
Vol 04 (04) ◽  
pp. 184-206 ◽  
Author(s):  
Kyousuke Kamada ◽  
Christoph Guger ◽  
Christine Salinas ◽  
Michael Westerveld ◽  
Eduardo Castillo ◽  
...  

2015 ◽  
Vol 74 (6) ◽  
Author(s):  
Norlaili Mat Safri ◽  
Siti Nurainn Fayyadhah Adnan

Eye therapy such as eye massages, has been designed to reduce eye problems and improve blood circulation of the eyes. When reading, the signs and symptoms of visual exhaustion are related to visual stress and people may make use of eye therapy to reduce this visual stress. It is well-known that a relaxed mind can be analysed via the study of an electroencephalogram signal. In this paper, we investigated the effect of eye therapy on visual stress by analysing brain signals (EEG) in frequency domain. Ten subjects participated. In the control task, subjects were asked to relax while EEG data were captured for two minutes. The next part was a visual test task, where the subjects were asked to search for a specific word in a text displayed on a computer screen while their EEG data were recorded. One visual test was performed without prior eye therapy, while the other three visual test tasks were performed following different eye therapy routines. The visual test task was completed fastest when subjects received eye drops and eye massages prior to the visual test. The difference between the visual test with and without prior eye therapy can be observed in the high-gamma frequency band, where with eye therapy, the high-gamma frequency band significantly increases in the frontal, temporal and occipital areas, and the word search performance was improved, with a shorter time needed to complete the task. In conclusion, the high-gamma frequency band may be an indicator to study visual stress, while specific eye-therapy routines may contribute to better eye and brain performance in word searching in a text displayed on a computer screen.


2013 ◽  
Vol 45 (3) ◽  
pp. 205-211 ◽  
Author(s):  
Milena Korostenskaja ◽  
Adam J. Wilson ◽  
Douglas F. Rose ◽  
Peter Brunner ◽  
Gerwin Schalk ◽  
...  

2019 ◽  
Author(s):  
Philémon Roussel ◽  
Gaël Le Godais ◽  
Florent Bocquelet ◽  
Marie Palma ◽  
Jiang Hongjie ◽  
...  

AbstractA current challenge of neurotechnologies is the development of speech brain-computer interfaces to restore communication in people unable to speak. To achieve a proof of concept of such system, neural activity of patients implanted for clinical reasons can be recorded while they speak. Using such simultaneously recorded audio and neural data, decoders can be built to predict speech features using features extracted from brain signals. A typical neural feature is the spectral power of field potentials in the high-gamma frequency band (between 70 and 200 Hz), a range that happens to overlap the fundamental frequency of speech. Here, we analyzed human electrocorticographic (ECoG) and intracortical recordings during speech production and perception as well as rat microelectrocorticographic (µ-ECoG) recordings during sound perception. We observed that electrophysiological signals, recorded with different recording setups, often contain spectrotemporal features highly correlated with those of the sound, especially within the high-gamma band. The characteristics of these correlated spectrotemporal features support a contamination of electrophysiological recordings by sound. In a recording showing high contamination, using neural features within the high-gamma frequency band dramatically increased the performance of linear decoding of acoustic speech features, while such improvement was very limited for another recording showing weak contamination. Further analysis and in vitro replication suggest that the contamination is caused by a mechanical action of the sound waves onto the cables and connectors along the recording chain, transforming sound vibrations into an undesired electrical noise that contaminates the biopotential measurements. This study does not question the existence of relevant physiological neural information underlying speech production or sound perception in the high-gamma frequency band, but alerts on the fact that care should be taken to evaluate and eliminate any possible acoustic contamination of neural signals in order to investigate the cortical dynamics of these processes.


2015 ◽  
Author(s):  
Jovana Belic ◽  
Per Halje ◽  
Ulrike Richter ◽  
Per Petersson ◽  
Jeanette Hellgren Kotaleski

We simultaneously recorded local field potentials in the primary motor cortex and sensorimotor striatum in awake, freely behaving, 6-OHDA lesioned hemi-parkinsonian rats in order to study the features directly related to pathological states such as parkinsonian state and levodopa-induced dyskinesia. We analysed the spectral characteristics of the obtained signals and observed that during dyskinesia the most prominent feature was a relative power increase in the high gamma frequency range at around 80 Hz, while for the parkinsonian state it was in the beta frequency range. Here we show that during both pathological states effective connectivity in terms of Granger causality is bidirectional with an accent on the striatal influence on the cortex. In the case of dyskinesia, we also found a high increase in effective connectivity at 80 Hz. In order to further understand the 80- Hz phenomenon, we performed cross-frequency analysis and observed characteristic patterns in the case of dyskinesia but not in the case of the parkinsonian state or the control state. We noted a large decrease in the modulation of the amplitude at 80 Hz by the phase of low frequency oscillations (up to ~10 Hz) across both structures in the case of dyskinesia. This may suggest a lack of coupling between the low frequency activity of the recorded network and the group of neurons active at ~80 Hz.


2005 ◽  
Vol 20 (1_suppl) ◽  
pp. S1-S56 ◽  
Author(s):  
James W. Wheless ◽  
Dave F. Clarke ◽  
Daniel Carpenter

Background. Childhood epilepsies are a heterogeneous group of conditions that differ in diagnostic criteria and management and have dramatically different outcomes. Despite increasing data on treatment of epilepsy, research findings on childhood epilepsy are more limited and many clinical questions remain unanswered, so that clinicians must often rely on clinical judgment. In such clinical situations, expert opinion can be especially helpful. Methods. A survey on pediatric epilepsy and seizures (33 questions and 645 treatment options) was sent to 41 U.S. physicians specializing in pediatric epilepsy, 39 (95%) of whom completed it. In some questions, the experts were asked to recommend overall treatment approaches for specific syndromes (the order in which they would use certain strategies). Most of the questions asked the experts to rate options using a modified version of the RAND 9-point scale for medical appropriateness. Consensus was defined as a non-random distribution of scores by chisquare test, with ratings used to assign a categorical rank (first line/usually appropriate, second line/equivocal, and third line/usually not appropriate) to each option. Results. Valproate was treatment of choice for symptomatic myoclonic and generalized tonic-clonic seizures except in the very young, with lamotrigine and topiramate also first line (usually appropriate). Zonisamide was first line only if the child also has myoclonic seizures. For initial monotherapy for complex partial seizures, oxcarbazepine and carbamazepine were treatments of choice, with lamotrigine and levetiracetam also first line. As initial therapy for infantile spasms caused by tuberous sclerosis, viagabatrin was treatment of choice, with adrenocorticotropic hormone (ACTH) also first line. As initial therapy for infantile spasms that are symptomatic in etiology, ACTH was treatment of choice, with topiramate also first line As initial therapy for Lennox-Gastaut syndrome, valproate was treatment of choice, with topiramate and lamotrigine also first line. For acute treatment of a prolonged febrile seizure or cluster of seizures, rectal diazepam was treatment of choice. For benign childhood epilepsy with centro-temporal spikes, oxcarbazepine and carbamazepine were treatments of choice, with gabapentin, lamotrigine, and levetiracetam also first line. For childhood absence epilepsy, ethosuximide was treatment of choice, with valproate and lamotrigine also first line. For juvenile absence epilepsy, valproate and lamotrigine were treatments of choice. For juvenile myoclonic epilepsy in adolescent males, valproate and lamotrigine were treatments of choice, with topiramate also first line; for juvenile myoclonic epilepsy in adolescent females, lamotrigine was treatment of choice, with topiramate and valproate other first-line options. As initial therapy for neonatal status epilepticus, intravenous phenobarbital was treatment of choice, with intravenous lorazepam or fosphenytoin also first line. As initial therapy for all types of pediatric status epilepticus, lorazepam was treatment of choice, with intravenous diazepam also first line. For generalized tonic-clonic status epilepticus, rectal diazepam and fosphenytoin were also first line; for complex partial status epilepticus, fosphenytoin was also first line; and for absence status epilepticus, intravenous valproate was also first line. Conclusion. The expert panel reached consensus on many treatment options. Within the limits of expert opinion and with the understanding that new research data may take precedence, the experts' recommendations provide helpful guidance in situations where the medical literature is scant or lacking. The information in this report should be evaluated in conjunction with evidence-based findings. (J Child Neurol 2005;20:Sl-S56)


2009 ◽  
Vol 9 (3) ◽  
pp. 72-74 ◽  
Author(s):  
Susan T. Herman

Rufinamide for Generalized Seizures Associated with Lennox–Gastaut Syndrome. Glauser T, Kluger G, Sachdeo R, Krauss G, Perdomo C, Arroyo S. Neurology 2008;70(21):1950–1958. BACKGROUND: Lennox–Gastaut syndrome is a catastrophic pediatric epilepsy syndrome characterized by multiple types of treatment-resistant seizures and high rates of seizure-related injury. Current available treatments are inadequate, leaving patients with few treatment options and opportunities. METHODS: We conducted a double-blind, randomized, placebo-controlled trial of the antiepileptic drug rufinamide in patients with Lennox–Gastaut syndrome. Eligible patients between 4 and 30 years of age had multiple types of seizures (including tonic–atonic and atypical absence seizures) with a minimum of 90 seizures in the month before baseline and a recent history of a slow spike-and-wave pattern on EEG. RESULTS: After a 28-day baseline period, 139 eligible patients were randomized; 138 patients received either rufinamide (n = 74) or placebo (n = 64) in addition to their other antiepileptic drugs. The median percentage reduction in total seizure frequency was greater in the rufinamide therapy group than in the placebo group (32.7% vs 11.7%, p = 0.0015). There was a difference ( p < 0.0001) in tonic–atonic (“drop attack”) seizure frequency with rufinamide (42.5% median percentage reduction) vs placebo (1.4% increase). The rufinamide group had a greater improvement in seizure severity ( p = 0.0041) and a higher 50% responder rate compared with placebo for total seizures ( p = 0.0045) and tonic–atonic seizures ( p = 0.002). The common adverse events (reported by 10% of patients receiving rufinamide) were somnolence (24.3% with rufinamide vs 12.5% with placebo) and vomiting (21.6% vs 6.3%). CONCLUSIONS: Rufinamide was an effective and well-tolerated treatment for seizures associated with Lennox–Gastaut syndrome.


2012 ◽  
Vol 107 (1) ◽  
pp. 424-432 ◽  
Author(s):  
Shin Yanagihara ◽  
Neal A. Hessler

The basal ganglia is thought to be critical for motor control and learning in mammals. In specific basal ganglia regions, gamma frequency oscillations occur during various behavioral states, including sleeping periods. Given the critical role of sleep in regulating vocal plasticity of songbirds, we examined the presence of such oscillations in the basal ganglia. In the song system nucleus Area X, epochs of high-gamma frequency (80–160 Hz) oscillation of local field potential during sleep were associated with phasic increases of neural activity. While birds were awake, activity of the same neurons increased specifically when birds were singing. Furthermore, during sleep there was a clear tendency for phase locking of spikes to these oscillations. Such patterned activity in the sleeping songbird basal ganglia could play a role in off-line processing of song system motor networks.


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