Publications by authors named "Greiner H"

Objective: The most common medically resistant epilepsy (MRE) involves the temporal lobe (TLE), and children designated as temporal plus epilepsy (TLE+) have a five-times increased risk of postoperative surgical failure. This retrospective, blinded, cross-sectional study aimed to correlate visual and computational analyses of magnetoencephalography (MEG) virtual sensor waveforms with surgical outcome and epilepsy classification (TLE and TLE+).

Methods: Patients with MRE who underwent MEG and iEEG monitoring and had at least 1 year of postsurgical follow-up were included in this retrospective analysis.

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Objective: Tuberous sclerosis complex (TSC) results from overactivity of the mechanistic target of rapamycin (mTOR). Sirolimus and everolimus are mTOR inhibitors that treat most facets of TSC but are understudied in infants. We sought to understand the safety and potential efficacy of preventative sirolimus in infants with TSC.

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Article Synopsis
  • The study investigates how different areas of the cerebral cortex exhibit varying daily rhythms of high-frequency oscillations (HFOs) in patients with drug-resistant epilepsy.
  • Stereotactic electroencephalography (EEG) was used to analyze HFOs across different brain regions, while filtering out data affected by seizures or artifacts.
  • Five distinct clusters were identified based on HFO patterns, which aligned with specific resting-state brain networks, suggesting a link between time-of-day variations in brain activity and functional connectivity.
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  • The study aimed to assess cognitive changes after surgery that involved removing areas of the brain with significant high-gamma power modulations (HGM) during a visual naming task, even though these areas were not identified as language-critical during standard electrical stimulation mapping.
  • Researchers analyzed the cognitive outcomes of 37 drug-resistant epilepsy patients one year after surgery, highlighting the effects of lesioning HGM language sites on various neuropsychological assessments, specifically measuring reliable change indices (RCIs).
  • Results showed that lesioning even one HGM language site was associated with significant declines in scores for vocabulary, working memory, and verbal learning, indicating that these areas play an important role in cognitive function, despite being categorized as non-language sites through electrical mapping.
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Article Synopsis
  • Ninety percent of patients with tuberous sclerosis complex (TSC) experience seizures, and about half have epilepsy that doesn't respond to medication.
  • A study explored how the size and number of seizure onset zones (SOZ) affect surgical outcomes in TSC patients who underwent epilepsy surgery.
  • The findings revealed that larger SOZ sizes and having more than one SOZ were linked to poorer surgical outcomes, suggesting that these characteristics could help predict the success of surgery in reducing seizures.
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Objective: We investigated the role of transverse temporal gyrus and adjacent cortex (TTG+) in facial expressions and perioral movements.

Methods: In 31 patients undergoing stereo-electroencephalography monitoring, we describe behavioral responses elicited by electrical stimulation within the TTG+. Task-induced high-gamma modulation (HGM), auditory evoked responses, and resting-state connectivity were used to investigate the cortical sites having different types of responses on electrical stimulation.

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Background And Objectives: Epilepsy surgery is often delayed. We previously developed machine learning (ML) models to identify candidates for resective epilepsy surgery earlier in the disease course. In this study, we report the prospective validation.

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Objective: The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail.

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In childhood, language outcomes following brain injury are inversely related to age. Neuroimaging findings suggest that extensive representation and/or topological redundancy may confer the pediatric advantage. Here, we assess whole brain and language network resilience using in silico attacks, for 85 children participating in a magnetoencephalography (MEG) study.

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Language comprehension is a complex process involving an extensive brain network. Brain regions responsible for prosodic processing have been studied in adults; however, much less is known about the neural bases of prosodic processing in children. Using magnetoencephalography (MEG), we mapped regions supporting speech envelope tracking (a marker of prosodic processing) in 80 typically developing children, ages 4-18 years, completing a stories listening paradigm.

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Objective: Transcranial Magnetic Stimulation (TMS) has emerged as a viable non-invasive method for mapping language networks. Little is known about the tolerability of transcranial magnetic stimulation language mapping in children.

Methods: Children aged 5-18 years underwent bilateral language mapping using repetitive transcranial magnetic stimulation (rTMS) to target 33 sites/hemisphere.

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Background And Purpose: We analyzed the association of neuropsychological outcomes after epilepsy surgery with the intracranial electrode type (stereo electroencephalography [SEEG] and subdural electrodes [SDE]), and electrical stimulation mapping (ESM) of speech/language.

Methods: Drug-resistant epilepsy patients who underwent comprehensive neuropsychological evaluation before and 1 year after epilepsy surgery were included. SEEG and SDE subgroups were matched by age, handedness, operated hemisphere, and seizure freedom.

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Objective: To determine whether automated, electronic alerts increased referrals for epilepsy surgery.

Methods: We conducted a prospective, randomized controlled trial of a natural language processing-based clinical decision support system embedded in the electronic health record (EHR) at 14 pediatric neurology outpatient clinic sites. Children with epilepsy and at least two prior neurology visits were screened by the system prior to their scheduled visit.

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Article Synopsis
  • The study compares the effectiveness and safety of electrical stimulation mapping (ESM) using subdural electrodes (SDE) and stereoelectroencephalography (SEEG) in functional brain localization for patients with epilepsy.
  • Results showed similar language and motor responses between the two methods, but SEEG had a higher incidence of sensory responses and less frequent afterdischarges (ADs) and EISs (unwanted seizures).
  • Overall, SEEG is considered a safer and more effective option for functional brain mapping due to its favorable thresholds and capacity for identifying sensory areas compared to SDE.
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Background: Posterior quadrant disconnection (PQD) has been described as a treatment for patients with refractory posterior quadrant subhemispheric epilepsy. Surgical outcomes are difficult to interpret because of limited literature.

Objective: To provide insight regarding the operative technique and postsurgical seizure freedom in young pediatric patients who underwent surgical disconnection for the treatment of posterior quadrant subhemispheric epilepsy at our institution.

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Objective: Seizures are known to occur with diurnal and other rhythms. To gain insight into the neurophysiology of periodicity of seizures, we tested the hypothesis that intracranial high-frequency oscillations (HFOs) show diurnal rhythms and sleep-wake cycle variation. We further hypothesized that HFOs have different rhythms within and outside the seizure-onset zone (SOZ).

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Objective: Patients with tuberous sclerosis complex (TSC) epilepsy present with unique clinical challenges such as early seizure onset and high rates of intractability and multifocality. Although there are numerous studies about the safety and efficacy of stereoelectroencephalography (SEEG), this topic has not been studied in TSC patients who have distinct epilepsy profiles. The authors investigated subdural grid (SDG) and SEEG monitoring to determine whether these procedures lead to similar seizure and safety outcomes and to identify features unique to this pediatric population.

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Objective: To clinically validate the connectivity-based magnetoencephalography (MEG) analyses to identify seizure onset zone (SOZ) with comparing to equivalent current dipole (ECD).

Methods: The ECD cluster was quantitatively analyzed by calculating the centroid of the cluster and maximum distance (the largest distance between all dipoles). The "primary hub" was determined by the highest eigencentrality.

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Objective: This systematic review and meta-analysis evaluated the diagnostic validity of functional magnetic resonance imaging (fMRI) compared to electrical stimulation mapping (ESM) for pre-surgical language mapping.

Methods: A structured literature search was performed and studies with electrode-level data comparing fMRI and ESM for language localization were analyzed. Outcome measures included pooled estimates of diagnostic odds ratio (DOR), sensitivity, and specificity.

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Objective: Pediatric epilepsy is characterized as drug resistant in 20%-30% of patients and defined as persistent seizures despite adequate treatment with two first-line antiepileptic medications. The American Academy of Neurology advocates surgical options earlier in the treatment of epilepsy to provide long-term seizure reduction. The new development of minimally invasive approaches has recently allowed for surgical options to patients not previously deemed surgical candidates.

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Background: Improvement in visual naming abilities throughout the childhood and adolescence supports development of higher-order linguistic skills. We investigated neuronal circuits underlying improvement in the speed of visual naming with age, and age-related dynamics of these circuits.

Methods: Response times were electronically measured during an overt visual naming task in epilepsy patients undergoing stereo-EEG monitoring.

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Purpose: Magnetoencephalography (MEG) defines the spike-generating zone and provides targets for invasive monitoring with stereotactic electroencephalography. This retrospective, blinded, cross-sectional study determined whether MEG virtual sensors could identify hippocampal epileptiform activity.

Methods: Using MEG beamformer analysis, virtual sensors were manually placed in bilateral hippocampi and corresponding virtual sensor waveforms were analyzed for the presence of epileptiform activity.

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Objective: Cerebral spatiotemporal dynamics of visual naming were investigated in epilepsy patients undergoing stereo-electroencephalography (SEEG) monitoring.

Methods: Brain networks were defined by Parcel-Activation-Resection-Symptom matching (PARS) approach by matching high-gamma (50-150 Hz) modulations (HGM) in neuroanatomic parcels during visual naming, with neuropsychological outcomes after resection/ablation of those parcels. Brain parcels with >50% electrode contacts simultaneously showing significant HGM were aligned, to delineate spatiotemporal course of naming-related HGM.

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Objective: Focal cortical dysplasia (FCD) is often associated with drug-resistant epilepsy, leading to a recommendation to surgically remove the seizure focus. Predicting outcome for resection of FCD is challenging, requiring a new approach. Lesion-symptom mapping is a powerful and broadly applicable method for linking neurological symptoms or outcomes to damage to particular brain regions.

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Objective: We evaluated SISCOM patterns and their relationship with surgical outcome in children with temporal lobe epilepsy (TLE) who had undergone a temporal lobe surgery.

Methods: This was an observational study evaluating SISCOM patterns in 40 children with TLE. We classified SISCOM patterns into 4 categories; (i) unilateral anteromesial and/or anterolateral temporal pattern; (ii) unilateral anteromesial and/or anterolateral temporal plus posterior extension pattern; (iii) bilateral anteromesial and/or anterolateral temporal pattern; and (iv) atypical pattern.

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