V rámci přípravy chirurgické terapie farmakorezistentní epilepsie představuje EEG registrace sfenoidálními elektrodami nenahraditelnou vyšetřovací metodu. Jejímu širšímu používání v EEG laboratořích však mnohdy brání nedostatek přesvědčení o přínosu či lokalizační přesnosti sfenoidálních elektrod, v porovnání s jinými elektrodami extrakraniálními. Srovnáním výsledků semiinvazivního EEG s výsledky skalpového a invazivníhn wšetření se proto autoři pokusili shrnout své dvouleté zkušenosti s EEG registrací prostřednictvím sfenoidálních elektrod. Retrospektivně byl zhodnocen soubor 35 pacientů, z toho 27 pacientů s epilepsií temporálního laloku. Potvrdila se významně vyšší výtěžnost EEG vyšetření za použití sfenoidálních elektrod ve srovnání s klasickým EEG vyšetřením. Při analýze interiktálních záznamů ve skupině pacientů s temporální epilepsií bylo zjištěno zvýšení senzitivity v lateralizaci specifického ložiska o 30 %. Při hodnocení iktáhiích záznamů se ještě výrazněji projevila výhoda sfenoidálních elektrod při odlišení meziotemporálního počátku iktáhií aktivity od laterálního neokortikálního. Nálezy byly verifikovány následným vyšetřením intracerebrálními elektrodami. Zvláštní pozornost byla věnována charakteru iktálních EEG vzorců ve sfenoidálních elektrodách.

Within the framework of preparations for surgery of pharmacoresistant epilepsy EEG recording by "leans of sphenoidal electrodes is an irreplaceable examination method. Its wider use in EEG laboratories is, however, frequently hampered by inadequate confidence in the asset or exact localization of sphenoidal electrodes as compared with other extracranial electrodes. By comparison of results of semiinvasive EEG with results of examinations with electrodes applied to the scalp and invasive examinations the authors tried therefore to summarize their two-year experience with EEG registration using sphenoidal electrodes. They evaluated retrospectively a group of 35 patients incl. 27 patients With epilepsy of the temporal lobe. TTiey confirmed a significantly higher yield of EEG examinations using sphenoidal electrodes as compared with classical EEG examination. Analysis of interictal records in the group of patients with temporal epilepsy revealed a greater sensitivity of lateralization of a specific focus by 30 %. On evaluation of ictal records the advantage of sphenoidal electrodes in the differentiation of a mesiotemporal onset of ictal activity from a neocortical one was even more marked. The findings were verified by subsequent examination using intracerebral electrodes. Special attention was devoted to the character of ictal EEG patterns in sphenoidal electrodes.

• MeSH
• elektroencefalografie metody   MeSH
• epilepsie chirurgie   MeSH
• implantované elektrody MeSH
• lidé MeSH
• Check Tag
• lidé MeSH

Postictal refractoriness checked by paired stimulations of the limbic structures was demonstrated to fail in rats<2 weeks old. Cortical epileptic afterdischarges were used in our study to examine if this phenomenon is restricted to old cortical structures or if it is a general one. Rats 12, 15, 18, 25, and 90 days old with implanted electrodes formed the experimental groups. Stimulation was performed by 15-s series of 1-msec pulses with suprathreshold intensity and frequency of 8 Hz. Paired stimulation of the cerebral cortex in 12-day-old rats elicited the second afterdischarge, even if the 30-s interval was used. Refractoriness started to appear in the third postnatal week and developed progressively so that 25-day-old rats did not differ from adult animals, that is, an interval longer than 1 min was necessary for elicitation of the second seizure.

• MeSH
• elektrická stimulace MeSH
• elektroencefalografie MeSH
• implantované elektrody MeSH
• krysa rodu rattus MeSH
• limbický systém růst a vývoj   fyziologie   MeSH
• mozková kůra růst a vývoj   fyziologie   MeSH
• novorozená zvířata MeSH
• refrakterní doba elektrofyziologická fyziologie   MeSH
• záchvaty patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

OBJECTIVE: Automated behavioral state classification in intracranial EEG (iEEG) recordings may be beneficial for iEEG interpretation and quantifying sleep patterns to enable behavioral state dependent neuromodulation therapy in next generation implantable brain stimulation devices. Here, we introduce a fully automated unsupervised framework to differentiate between awake (AW), sleep (N2), and slow wave sleep (N3) using intracranial EEG (iEEG) only and validated with expert scored polysomnography. APPROACH: Data from eight patients undergoing evaluation for epilepsy surgery (age [Formula: see text], three female) with intracranial depth electrodes for iEEG monitoring were included. Spectral power features (0.1-235 Hz) spanning several frequency bands from a single electrode were used to classify behavioral states of patients into AW, N2, and N3. MAIN RESULTS: Overall, classification accuracy of 94%, with 94% sensitivity and 93% specificity across eight subjects using multiple spectral power features from a single electrode was achieved. Classification performance of N3 sleep was significantly better (95%, sensitivity 95%, specificity 93%) than that of the N2 sleep phase (87%, sensitivity 78%, specificity 96%). SIGNIFICANCE: Automated, unsupervised, and robust classification of behavioral states based on iEEG data is possible, and it is feasible to incorporate these algorithms into future implantable devices with limited computational power, memory, and number of electrodes for brain monitoring and stimulation.

• MeSH
• algoritmy MeSH
• bdění fyziologie   MeSH
• chování fyziologie   MeSH
• dospělí MeSH
• elektrokortikografie metody   MeSH
• epilepsie chirurgie   MeSH
• hluboká mozková stimulace MeSH
• implantované elektrody MeSH
• lidé středního věku MeSH
• lidé MeSH
• polysomnografie MeSH
• reprodukovatelnost výsledků MeSH
• spánek pomalých vln fyziologie   MeSH
• stadia spánku fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

DNA methylation plays an important role in physiological and pathological processes. Several genetic diseases and most malignancies tend to be associated with aberrant DNA methylation. Among other analytical methods, electrochemical approaches have been successfully employed for characterisation of DNA methylation patterns that are essential for the diagnosis and treatment of particular diseases. This article discusses current trends in the electrochemical sensing and biosensing of DNA methylation. Particularly, it provides an overview of applied electrode materials, electrode modifications and biorecognition elements applications with an emphasis on strategies that form the core DNA methylation detection approaches. The three main strategies as (i) bisulfite treatment, (ii) cleavage by restriction endonucleases, and (iii) immuno/affinity reaction were described in greater detail. Additionally, the availability of the reviewed platforms for early cancer diagnosis and the approval of methylation inhibitors for anticancer therapy were discussed.

• MeSH
• biosenzitivní techniky přístrojové vybavení   metody   MeSH
• DNA analýza   genetika   MeSH
• elektrochemické techniky přístrojové vybavení   metody   MeSH
• elektrody MeSH
• lidé MeSH
• metylace DNA * MeSH
• nádory diagnóza   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

• MeSH
• algoritmy MeSH
• elektrody využití   MeSH
• elektromyografie metody   přístrojové vybavení   využití   MeSH
• horní končetina MeSH
• lidé MeSH
• počítačové zpracování signálu MeSH
• statistika jako téma MeSH
• Check Tag
• lidé MeSH

Interictal epileptiform discharges (spikes, IEDs) are electrographic markers of epileptic tissue and their quantification is utilized in planning of surgical resection. Visual analysis of long-term multi-channel intracranial recordings is extremely laborious and prone to bias. Development of new and reliable techniques of automatic spike detection represents a crucial step towards increasing the information yield of intracranial recordings and to improve surgical outcome. In this study, we designed a novel and robust detection algorithm that adaptively models statistical distributions of signal envelopes and enables discrimination of signals containing IEDs from signals with background activity. This detector demonstrates performance superior both to human readers and to an established detector. It is even capable of identifying low-amplitude IEDs which are often missed by experts and which may represent an important source of clinical information. Application of the detector to non-epileptic intracranial data from patients with intractable facial pain revealed the existence of sharp transients with waveforms reminiscent of interictal discharges that can represent biological sources of false positive detections. Identification of these transients enabled us to develop and propose secondary processing steps, which may exclude these transients, improving the detector's specificity and having important implications for future development of spike detectors in general.

• MeSH
• algoritmy MeSH
• analýza hlavních komponent MeSH
• chronická bolest diagnóza   patofyziologie   MeSH
• dítě MeSH
• dospělí MeSH
• elektroencefalografie metody   MeSH
• epilepsie diagnóza   patofyziologie   MeSH
• falešně negativní reakce MeSH
• falešně pozitivní reakce MeSH
• implantované elektrody MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mozek patofyziologie   MeSH
• obličejová bolest diagnóza   patofyziologie   MeSH
• počítačové zpracování signálu MeSH
• rozpoznávání automatizované metody   MeSH
• senzitivita a specificita MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Until now there has been no way of distinguishing between physiological and epileptic hippocampal ripples in intracranial recordings. In the present study we addressed this by investigating the effect of cognitive stimulation on interictal high frequency oscillations in the ripple range (80-250 Hz) within epileptic (EH) and non-epileptic hippocampus (NH). METHODS: We analyzed depth EEG recordings in 10 patients with intractable epilepsy, in whom hippocampal activity was recorded initially during quiet wakefulness and subsequently during a simple cognitive task. Using automated detection of ripples based on amplitude of the power envelope, we analyzed ripple rate (RR) in the cognitive and resting period, within EH and NH. RESULTS: Compared to quiet wakefulness we observed a significant reduction of RR during cognitive stimulation in EH, while it remained statistically marginal in NH. Further, we investigated the direct impact of cognitive stimuli on ripples (i.e. immediately post-stimulus), which showed a transient statistically significant suppression of ripples in the first second after stimuli onset in NH only. CONCLUSION: Our results point to a differential reactivity of ripples within EH and NH to cognitive stimulation.

• MeSH
• bdění MeSH
• dospělí MeSH
• elektroencefalografie MeSH
• epilepsie patofyziologie   MeSH
• hipokampus patofyziologie   MeSH
• implantované elektrody MeSH
• kognice fyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• neuropsychologické testy MeSH
• odpočinek MeSH
• rozpoznávání automatizované MeSH
• zraková percepce fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Epidural spinal cord stimulation (ESCS) is widely used for chronic pain treatment, and is also a promising tool for restoring motor function after spinal cord injury. Despite significant positive impact of ESCS, currently available protocols provide limited specificity and efficiency partially due to the limited number of contacts of the leads and to the limited flexibility to vary the spatial distribution of the stimulation field in respect to the spinal cord. Recently, we introduced Orientation Selective (OS) stimulation strategies for deep brain stimulation, and demonstrated their selectivity in rats using functional MRI (fMRI). The method achieves orientation selectivity by controlling the main direction of the electric field gradients using individually driven channels. Here, we introduced a similar OS approach for ESCS, and demonstrated orientation dependent brain activations as detected by brain fMRI. The fMRI activation patterns during spinal cord stimulation demonstrated the complexity of brain networks stimulated by OS-ESCS paradigms, involving brain areas responsible for the transmission of the motor and sensory information. The OS approach may allow targeting ESCS to spinal fibers of different orientations, ultimately making stimulation less dependent on the precision of the electrode implantation.

• MeSH
• epidurální prostor diagnostické zobrazování   patofyziologie   MeSH
• implantované elektrody MeSH
• krysa rodu rattus MeSH
• magnetická rezonanční tomografie * MeSH
• míšní stimulace * MeSH
• poranění míchy * diagnostické zobrazování   patofyziologie   terapie   MeSH
• potkani Sprague-Dawley MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Objective.Understanding how the retina converts a natural image or an electrically stimulated one into neural firing patterns is the focus of on-going research activities.Ex vivo, the retina can be readily investigated using multi electrode arrays (MEAs). However, MEA recording and stimulation from an intact retina (in the eye) has been so far insufficient.Approach.In the present study, we report new soft carbon electrode arrays suitable for recording and stimulating neural activity in an intact retina. Screen-printing of carbon ink on 20μm polyurethane (PU) film was used to realize electrode arrays with electrodes as small as 40μm in diameter. Passivation was achieved with a holey membrane, realized using laser drilling in a thin (50μm) PU film. Plasma polymerized 3.4-ethylenedioxythiophene was used to coat the electrode array to improve the electrode specific capacitance. Chick retinas, embryonic stage day 13, both explanted and intact inside an enucleated eye, were used.Main results.A novel fabrication process based on printed carbon electrodes was developed and yielded high capacitance electrodes on a soft substrate.Ex vivoelectrical recording of retina activity with carbon electrodes is demonstrated. With the addition of organic photo-capacitors, simultaneous photo-electrical stimulation and electrical recording was achieved. Finally, electrical activity recordings from an intact chick retina (inside enucleated eyes) were demonstrated. Both photosensitive retinal ganglion cell responses and spontaneous retina waves were recorded and their features analyzed.Significance.Results of this study demonstrated soft electrode arrays with unique properties, suitable for simultaneous recording and photo-electrical stimulation of the retina at high fidelity. This novel electrode technology opens up new frontiers in the study of neural tissuein vivo.

• MeSH
• elektrická stimulace metody   MeSH
• mikroelektrody MeSH
• retina * fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVE: Automated behavioral state classification can benefit next generation implantable epilepsy devices. In this study we explored the feasibility of automated awake (AW) and slow wave sleep (SWS) classification using wide bandwidth intracranial EEG (iEEG) in patients undergoing evaluation for epilepsy surgery. APPROACH: Data from seven patients (age [Formula: see text], 4 women) who underwent intracranial depth electrode implantation for iEEG monitoring were included. Spectral power features (0.1-600 Hz) spanning several frequency bands from a single electrode were used to train and test a support vector machine classifier. MAIN RESULTS: Classification accuracy of 97.8  ±  0.3% (normal tissue) and 89.4  ±  0.8% (epileptic tissue) across seven subjects using multiple spectral power features from a single electrode was achieved. Spectral power features from electrodes placed in normal temporal neocortex were found to be more useful (accuracy 90.8  ±  0.8%) for sleep-wake state classification than electrodes located in normal hippocampus (87.1  ±  1.6%). Spectral power in high frequency band features (Ripple (80-250 Hz), Fast Ripple (250-600 Hz)) showed comparable performance for AW and SWS classification as the best performing Berger bands (Alpha, Beta, low Gamma) with accuracy  ⩾90% using a single electrode contact and single spectral feature. SIGNIFICANCE: Automated classification of wake and SWS should prove useful for future implantable epilepsy devices with limited computational power, memory, and number of electrodes. Applications include quantifying patient sleep patterns and behavioral state dependent detection, prediction, and electrical stimulation therapies.

• MeSH
• algoritmy * MeSH
• diagnóza počítačová metody   MeSH
• dospělí MeSH
• elektrokortikografie metody   MeSH
• epilepsie diagnóza   patofyziologie   MeSH
• hipokampus patofyziologie   MeSH
• lidé MeSH
• reprodukovatelnost výsledků MeSH
• rozpoznávání automatizované metody   MeSH
• senzitivita a specificita MeSH
• stadia spánku * MeSH
• strojové učení MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH