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1.
World Neurosurg ; 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32014543

RESUMO

BACKGROUND: Research experience is believed to be an important component of the neurosurgery residency application process. One measure of research productivity is publication volume. The preresidency publication volume of U.S. neurosurgery interns and any potential association between applicant publication volume and the match results of top-ranked residency programs have not been well characterized. OBJECTIVE: In this study, we sought to characterize the preresidency publication volume of U.S. neurosurgery residents in the 2018-2019 intern class using the Scopus database. METHODS: For each intern, we recorded the total number of publications, total number of first or last author publications, total number of neuroscience-related publications, mean number of citations per publication, and mean impact factor of the journal per publication. Preresidency publication volumes of interns at the top-25 programs (based on a composite ranking score according to 4 different ranking metrics) were compared with those at all other programs. RESULTS: We found that 82% of neurosurgery interns included in the analysis (190 interns from 95 programs) had at least 1 publication. The average number of publications per intern among all programs was 6 ± 0.63 (mean ± standard error of the mean). We also found that interns at top-25 neurosurgery residency programs tended to have a higher number of publications (8.3 ± 1.2 vs. 4.8 ± 0.7, P = 0.0137), number of neuroscience-related publications (6.8 ± 1.1 vs. 4.1 ± 0.7, P = 0.0419), and mean number of citations per publication (9.8 ± 1.7 vs. 5.7 ± 0.8, P = 0.0267) compared with interns at all other programs. CONCLUSIONS: Our results provide a general estimate of the preresidency publication volume of U.S. neurosurgery interns and suggest a potential association between publication volume and matching in the top-25 neurosurgery residency programs.

2.
Cereb Cortex ; 29(2): 461-474, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29194517

RESUMO

Conscious perception occurs within less than 1 s. To study events on this time scale we used direct electrical recordings from the human cerebral cortex during a conscious visual perception task. Faces were presented at individually titrated visual threshold for 9 subjects while measuring broadband 40-115 Hz gamma power in a total of 1621 intracranial electrodes widely distributed in both hemispheres. Surface maps and k-means clustering analysis showed initial activation of visual cortex for both perceived and non-perceived stimuli. However, only stimuli reported as perceived then elicited a forward-sweeping wave of activity throughout the cerebral cortex accompanied by large-scale network switching. Specifically, a monophasic wave of broadband gamma activation moves through bilateral association cortex at a rate of approximately 150 mm/s and eventually reenters visual cortex for perceived but not for non-perceived stimuli. Meanwhile, the default mode network and the initial visual cortex and higher association cortex networks are switched off for the duration of conscious stimulus processing. Based on these findings, we propose a new "switch-and-wave" model for the processing of consciously perceived stimuli. These findings are important for understanding normal conscious perception and may also shed light on its vulnerability to disruption by brain disorders.

3.
Epilepsia ; 59(11): 2075-2085, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30187919

RESUMO

OBJECTIVE: Studies of infraslow amplitude modulations (<0.15 Hz) of band power time series suggest that these envelope correlations may form a basis for distant spatial coupling in the brain. In this study, we sought to determine how infraslow relationships are affected by antiepileptic drug (AED) taper, time of day, and seizure. METHODS: We studied intracranial electroencephalographic (icEEG) data collected from 13 medically refractory adult epilepsy patients who underwent monitoring at Yale-New Haven Hospital. We estimated the magnitude-squared coherence (MSC) at <0.15 Hz of traditional EEG frequency band power time series for all electrode contact pairs to quantify infraslow envelope correlations between them. We studied, first, hour-long background icEEG epochs before and after AED taper to understand the effect of taper. Second, we analyzed the entire record for each patient to study the effect of time of day. Finally, for each patient, we reviewed the clinical record to find all seizures that were at least 6 hours removed from other seizures and analyzed infraslow envelope MSC before and after them. RESULTS: Infraslow envelope MSC increased slightly, but significantly, after AED taper, and increased on average during the night and decreased during the day. It was also increased significantly in all frequency bands up to 3 hours preseizure and 1 hour postseizure as compared to background icEEG (61 seizures studied). These changes occurred for both daytime and nighttime seizures (28 daytime, 33 nighttime). Interestingly, there was significant spatial variability to these changes, with the seizure onset area peaking at 3 hours preseizure, then showing progressive desynchronization from 3 hours preseizure to 1 hour postseizure. SIGNIFICANCE: Infraslow envelope analysis may be used to understand long-term changes over the course of icEEG monitoring, provide unique insight into interictal electrophysiological changes related to ictogenesis, and contribute to the development of novel seizure forecasting algorithms.


Assuntos
Mapeamento Encefálico , Ondas Encefálicas/fisiologia , Epilepsia Resistente a Medicamentos/fisiopatologia , Eletrocorticografia , Convulsões/fisiopatologia , Adulto , Anticonvulsivantes/uso terapêutico , Ondas Encefálicas/efeitos dos fármacos , Epilepsia Resistente a Medicamentos/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Processamento de Sinais Assistido por Computador , Fatores de Tempo , Adulto Jovem
4.
Front Neurosci ; 12: 474, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30108472

RESUMO

Seizures have traditionally been considered hypersynchronous excitatory events and epilepsy has been separated into focal and generalized epilepsy based largely on the spatial distribution of brain regions involved at seizure onset. Epilepsy, however, is increasingly recognized as a complex network disorder that may be distributed and dynamic. Responsive neurostimulation (RNS) is a recent technology that utilizes intracranial electroencephalography (EEG) to detect seizures and delivers stimulation to cortical and subcortical brain structures for seizure control. RNS has particular significance in the clinical treatment of medically refractory epilepsy and brain-computer interfaces in epilepsy. Closed loop RNS represents an important step forward to understand and target nodes in the seizure network. The thalamus is a central network node within several functional networks and regulates input to the cortex; clinically, several thalamic nuclei are safe and feasible targets. We highlight the network theory of epilepsy, potential targets for neuromodulation in epilepsy and the first reported use of RNS as a first generation brain-computer interface to detect and stimulate the centromedian intralaminar thalamic nucleus in a patient with bilateral cortical onset of seizures. We propose that advances in network analysis and neuromodulatory techniques using brain-computer interfaces will significantly improve outcomes in patients with epilepsy. There are numerous avenues of future direction in brain-computer interface devices including multi-modal sensors, flexible electrode arrays, multi-site targeting, and wireless communication.

5.
Curr Treat Options Neurol ; 20(8): 34, 2018 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-30019165

RESUMO

PURPOSE OF REVIEW: Management of patients with subdural hematomas starts with Emergency Neurological Life Support guidelines. Patients with acute or chronic subdural hematomas (SDHs) associated with rapidly deteriorating neurologic exam, unilaterally or bilaterally dilated nonreactive pupils, and extensor posturing are considered imminently surgical; likewise, SDHs more than 10 mm in size or those associated with more than 5-mm midline shift are deemed operative. RECENT FINDINGS: While twist drill craniostomy and placement of subdural evacuating vport system (SEPS) are quick, bedside procedures completed under local anesthesia and appropriate for patients with chronic SDH or patients that cannot tolerate anesthesia, these techniques are not optimal for patients with acute SDH or chronic SDH with septations. Burr hole SDH evacuation under conscious sedation or general anesthesia is an analogous technique; however, it requires basic surgical equipment and operating room staff, with a focus on a closed system with burr hole followed by rapid drain placement to avoid introduction of air into the subdural space, or multiple burr holes with extensive irrigation to reduce pneumocephalus and continue SDH evacuation via drain for several days. Acute SDH associated with significant mass effect and cerebral edema requires aggressive decompression via craniotomy with clot evacuation and frequently a craniectomy. Chronic SDHs that fail conservative management and progress clinically or radiographically are addressed with craniotomy with or without membranectomy. Surgical SDH management is variable depending on its characteristics and etiology, patient's functional status, comorbidities, goals of care, institutional preferences, and availability of specialized surgical equipment and adjunct therapies. Rapid access to surgical suites and trained staff to address surgical hemorrhages in a timely manner, with appropriate post-operative care by a specialized team including neurosurgeons and neurointensivists, is of paramount importance for successful patient outcomes. Here, we review various aspects of surgical SDH management.

6.
Curr Treat Options Neurol ; 20(8): 28, 2018 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-29936548

RESUMO

PURPOSE OF REVIEW: Subdural hematomas (SDH) represent common neurosurgical problem associated with significant morbidity, mortality, and high recurrence rates. SDH incidence increases with age; numbers of patients affected by SDH continue to rise with our aging population and increasing number of people taking antiplatelet agents or anticoagulation. Medical and surgical SDH management remains a subject of investigation. RECENT FINDINGS: Initial management of patients with concern for altered mental status with or without trauma starts with Emergency Neurological Life Support (ENLS) guidelines, with a focus on maintaining ICP < 22 mmHg, CPP > 60 mmHg, MAP 80-110 mmHg, and PaO2 > 60 mmHg, followed by rapid sequence intubation if necessary, and expedited acquisition of imaging to identify a space-occupying lesion. Patients are administered anti-seizure medications, and their antiplatelet medications or anticoagulation may be reversed if neurosurgical interventions are anticipated, or until hemorrhage is stabilized on imaging. Medical SDH care focuses on (a) management of intracranial hypertension; (b) maintenance of adequate cerebral perfusion; (c) seizure prevention and treatment; (d) maintenance of normothermia, eucarbia, euglycemia, and euvolemia; and (e) early initiation of enteral feeding, mobilization, and physical therapy. Post-operatively, SDH patients require ICU level care and are co-managed by neurointensivists with expertise in treating increased intracranial pressure, seizures, and status epilepticus, as well as medical complications of critical illness. Here, we review various aspects of medical management with a brief overview of pertinent literature and clinical trials for patients diagnosed with SDH.

7.
Lancet Neurol ; 17(4): 373-382, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29553383

RESUMO

Intracranial electrophysiological recording in patients with refractory focal epilepsy is the gold standard for defining epileptogenic tissue. Although the concordance of intracranial electrophysiology, structural MRI, and pathology can identify brain regions for resection, complete seizure control after surgery is not achieved in all patients with focal epilepsy. Repetitive identical behavioural seizures suggest one onset area, but epileptogenesis might be distributed and connected by functional and structural brain networks outside the seizure onset area, which could explain poor postsurgical outcomes in some patients. Similar networks are postulated in neuropsychiatric disorders, such as depression and anxiety, and seem to overlap with posited epilepsy networks, perhaps explaining the high prevalence of comorbid neuropsychiatric disorders in patients with epilepsy. These networks are difficult to verify with available electrophysiological recording approaches. Advances in intracranial technology are needed to confirm the epilepsy network hypothesis and improve surgical outcomes by providing individualised therapies based on specific network contributions.


Assuntos
Encéfalo/cirurgia , Epilepsias Parciais/cirurgia , Transtornos Mentais/complicações , Rede Nervosa/cirurgia , Convulsões/cirurgia , Encéfalo/fisiopatologia , Eletroencefalografia , Epilepsias Parciais/complicações , Epilepsias Parciais/fisiopatologia , Humanos , Rede Nervosa/fisiopatologia , Convulsões/complicações , Convulsões/fisiopatologia
8.
J Neurol Neurosurg Psychiatry ; 89(8): 886-896, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29371415

RESUMO

OBJECTIVE: Refractory psychiatric disease is a major cause of morbidity and mortality worldwide, and there is a great need for new treatments. In the last decade, investigators piloted novel deep brain stimulation (DBS)-based therapies for depression and obsessive-compulsive disorder (OCD). Results from recent pivotal trials of these therapies, however, did not demonstrate the degree of efficacy expected from previous smaller trials. To discuss next steps, neurosurgeons, neurologists, psychiatrists and representatives from industry convened a workshop sponsored by the American Society for Stereotactic and Functional Neurosurgery in Chicago, Illinois, in June of 2016. DESIGN: Here we summarise the proceedings of the workshop. Participants discussed a number of issues of importance to the community. First, we discussed how to interpret results from the recent pivotal trials of DBS for OCD and depression. We then reviewed what can be learnt from lesions and closed-loop neurostimulation. Subsequently, representatives from the National Institutes of Health, the Food and Drug Administration and industry discussed their views on neuromodulation for psychiatric disorders. In particular, these third parties discussed their criteria for moving forward with new trials. Finally, we discussed the best way of confirming safety and efficacy of these therapies, including registries and clinical trial design. We close by discussing next steps in the journey to new neuromodulatory therapies for these devastating illnesses. CONCLUSION: Interest and motivation remain strong for deep brain stimulation for psychiatric disease. Progress will require coordinated efforts by all stakeholders.


Assuntos
Transtornos Mentais/cirurgia , Neurocirurgia , Procedimentos Neurocirúrgicos/métodos , Humanos , Estados Unidos
10.
J Neurosurg ; 125(Suppl 1): 154-159, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27903196

RESUMO

OBJECTIVE Functional Gamma Knife radiosurgery (GKRS) procedures have been increasingly used for treating patients with tremor, trigeminal neuralgia (TN), and refractory obsessive-compulsive disorder. Although its rates of toxicity are low, GKRS has been associated with some, if low, risks for serious sequelae, including hemiparesis and even death. Anecdotal reports have suggested that even with a standardized prescription dose, rates of functional GKRS toxicity increase after replacement of an old cobalt-60 source with a new source. Dose rate changes over the course of the useful lifespan of cobalt-60 are not routinely considered in the study of patients treated with functional GKRS, but these changes may be associated with significant variation in the biologically effective dose (BED) delivered to neural tissue. METHODS The authors constructed a linear-quadratic model of BED in functional GKRS with a dose-protraction factor to correct for intrafraction DNA-damage repair and used standard single-fraction doses for trigeminal nerve ablation for TN (85 Gy), thalamotomy for tremor (130 Gy), and capsulotomy for obsessive-compulsive disorder (180 Gy). Dose rate and treatment time for functional GKRS involving 4-mm collimators were derived from calibrations in the authors' department and from the cobalt-60 decay rate. Biologically plausible values for the ratio for radiosensitivity to fraction size (α/ß) and double-strand break (DSB) DNA repair halftimes (τ) were estimated from published experimental data. The biphasic characteristics of DSB repair in normal tissue were accounted for in deriving an effective τ1 halftime (fast repair) and τ2 halftime (slow repair). A sensitivity analysis was performed with a range of plausible parameter values. RESULTS After replacement of the cobalt-60 source, the functional GKRS dose rate rose from 1.48 to 2.99 Gy/min, treatment time fell, and estimated BED increased. Assuming the most biologically plausible parameters, source replacement resulted in an immediate relative BED increase of 11.7% for GKRS-based TN management with 85 Gy, 15.6% for thalamotomy with 130 Gy, and 18.6% for capsulotomy with 180 Gy. Over the course of the 63-month lifespan of the cobalt-60 source, BED decreased annually by 2.2% for TN management, 3.0% for thalamotomy, and 3.5% for capsulotomy. CONCLUSIONS Use of a new cobalt-60 source after replacement of an old source substantially increases the predicted BED for functional GKRS treatments for the same physical dose prescription. Source age, dose rate, and treatment time should be considered in the study of outcomes after high-dose functional GKRS treatments. Animal and clinical studies are needed to determine how this potential change in BED contributes to GKRS toxicity and whether technical adjustments should be made to reduce dose rates or prescription doses with newer cobalt-60 sources.


Assuntos
Radioisótopos de Cobalto/uso terapêutico , Radiocirurgia/métodos , Humanos , Dosagem Radioterapêutica , Eficiência Biológica Relativa
11.
Clin Neurophysiol ; 127(11): 3485-3491, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27692590

RESUMO

OBJECTIVE: We examined low-frequency amplitude modulations of band power time-series, i.e. the second spectrum, of the intracranial EEG (icEEG) for evidence of support for spatial relationships between different parts of the brain and within the default mode network (DMN). METHODS: We estimated magnitude-squared coherence (MSC) of the running power in the delta, theta, alpha, beta, and gamma frequency bands for one-hour background icEEG epochs recorded from 9 patients. We isolated two test areas within the DMN and one control area outside it. We tested if the relationship between DMN areas was stronger than the relationship between each of these areas and the control location, and between all intrahemispheric contact pairs with similar intercontact distance. RESULTS: We observed very low values of second spectrum relationship between different parts of the brain, except at very short distances. These relationships are strongest in the delta band and decrease with increasing frequency, with gamma band relationships being the weakest. Our DMN-specific analysis showed no enhanced connectivity in the second spectrum in DMN locations in any frequency band. CONCLUSIONS: Though we observed significantly nonzero relationships in lower frequency bands, second spectrum relationships are consistently very low across the entire brain in every frequency band. SIGNIFICANCE: This study suggests a lack of support for the DMN in the icEEG second spectrum.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Eletroencefalografia/métodos , Rede Nervosa/fisiologia , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Distribuição Aleatória , Adulto Jovem
12.
Clin Neurophysiol ; 127(5): 2302-7, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27072103

RESUMO

OBJECTIVE: We evaluated changes to sleep structure during continuous intracranial EEG (icEEG) monitoring of epilepsy patients undergoing localization of the seizure onset area. METHODS: We studied 28 adult epilepsy patients who underwent icEEG monitoring for a median of 12 nights. We used a metric calculated from relative delta power (RDP) to evaluate the emergence of sleep cycles for every night of monitoring. We further evaluated the effect of seizures and AEDs on trends in the RDP metric. RESULTS: We observed oscillations corresponding to sleep cycles in the RDP time-series. There was a significant increasing trend in our RDP sleep metric over the course of monitoring. Seizures and AEDs did not significantly affect this trend. CONCLUSIONS: The RDP metric increased during icEEG monitoring, independent of seizures and AEDs. This increase may be due to a number of factors and these factors appear to outweigh the effects of seizures and AEDs. SIGNIFICANCE: Our results indicate that sleep is not uniform during icEEG monitoring, rather there is a considerable increasing, multi-night change in sleep structure.


Assuntos
Encéfalo/fisiopatologia , Epilepsia/fisiopatologia , Sono/fisiologia , Adolescente , Adulto , Mapeamento Encefálico , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
J Neurosci ; 35(44): 14771-82, 2015 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-26538648

RESUMO

UNLABELLED: Hippocampal sharp-wave ripples (SWRs) are highly synchronous oscillatory field potentials that are thought to facilitate memory consolidation. SWRs typically occur during quiescent states, when neural activity reflecting recent experience is replayed. In rodents, SWRs also occur during brief locomotor pauses in maze exploration, where they appear to support learning during experience. In this study, we detected SWRs that occurred during quiescent states, but also during goal-directed visual exploration in nonhuman primates (Macaca mulatta). The exploratory SWRs showed peak frequency bands similar to those of quiescent SWRs, and both types were inhibited at the onset of their respective behavioral epochs. In apparent contrast to rodent SWRs, these exploratory SWRs occurred during active periods of exploration, e.g., while animals searched for a target object in a scene. SWRs were associated with smaller saccades and longer fixations. Also, when they coincided with target-object fixations during search, detection was more likely than when these events were decoupled. Although we observed high gamma-band field potentials of similar frequency to SWRs, only the SWRs accompanied greater spiking synchrony in neural populations. These results reveal that SWRs are not limited to off-line states as conventionally defined; rather, they occur during active and informative performance windows. The exploratory SWR in primates is an infrequent occurrence associated with active, attentive performance, which may indicate a new, extended role of SWRs during exploration in primates. SIGNIFICANCE STATEMENT: Sharp-wave ripples (SWRs) are high-frequency oscillations that generate highly synchronized activity in neural populations. Their prevalence in sleep and quiet wakefulness, and the memory deficits that result from their interruption, suggest that SWRs contribute to memory consolidation during rest. Here, we report that SWRs from the monkey hippocampus occur not only during behavioral inactivity but also during successful visual exploration. SWRs were associated with attentive, focal search and appeared to enhance perception of locations viewed around the time of their occurrence. SWRs occurring in rest are noteworthy for their relation to heightened neural population activity, temporally precise and widespread synchronization, and memory consolidation; therefore, the SWRs reported here may have a similar effect on neural populations, even as experiences unfold.


Assuntos
Potenciais de Ação/fisiologia , Ondas Encefálicas/fisiologia , Movimentos Oculares/fisiologia , Hipocampo/fisiologia , Estimulação Luminosa/métodos , Percepção Visual/fisiologia , Animais , Feminino , Macaca mulatta , Masculino
14.
J Neurophysiol ; 114(2): 1248-54, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26084904

RESUMO

A widely accepted view is that wakefulness is a state in which the entire cortical mantle is persistently activated, and therefore desynchronized. Consequently, the EEG is dominated by low-amplitude, high-frequency fluctuations. This view is currently under revision because the 1-4 Hz delta rhythm is often evident during "quiet" wakefulness in rodents and nonhuman primates. Here we used intracranial EEG recordings to assess the occurrence of delta rhythm in 18 awake human beings. Our recordings reveal rhythmic delta during wakefulness at 10% of all recording sites. Delta rhythm could be observed in a single cortical lobe or in multiple lobes. Sites with high delta could flip between high and low delta power or could be in a persistently high delta state. Finally, these sites were rarely identified as the sites of seizure onset. Thus rhythmic delta can dominate the background operation and activity of some neocortical circuits in awake human beings.


Assuntos
Córtex Cerebral/fisiologia , Ritmo Delta/fisiologia , Vigília/fisiologia , Adulto , Córtex Cerebral/fisiopatologia , Córtex Cerebral/cirurgia , Eletrocorticografia , Eletrodos Implantados , Epilepsia/fisiopatologia , Epilepsia/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Convulsões/fisiopatologia , Convulsões/cirurgia , Adulto Jovem
15.
Neurosurg Focus ; 38(6): E10, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26030698

RESUMO

When drug-resistant epilepsy is poorly localized or surgical resection is contraindicated, current neurostimulation strategies such as deep brain stimulation and vagal nerve stimulation can palliate the frequency or severity of seizures. However, despite medical and neuromodulatory therapy, a significant proportion of patients continue to experience disabling seizures that impair awareness, causing disability and risking injury or sudden unexplained death. We propose a novel strategy in which neuromodulation is used not only to reduce seizures but also to ameliorate impaired consciousness when the patient is in the ictal and postictal states. Improving or preventing alterations in level of consciousness may have an effect on morbidity (e.g., accidents, drownings, falls), risk for death, and quality of life. Recent studies may have elucidated underlying networks and mechanisms of impaired consciousness and yield potential novel targets for neuromodulation. The feasibility, benefits, and pitfalls of potential deep brain stimulation targets are illustrated in human and animal studies involving minimally conscious/vegetative states, movement disorders, depth of anesthesia, sleep-wake regulation, and epilepsy. We review evidence that viable therapeutic targets for impaired consciousness associated with seizures may be provided by key nodes of the consciousness system in the brainstem reticular activating system, hypothalamus, basal ganglia, thalamus, and basal forebrain.


Assuntos
Encéfalo/fisiologia , Estado de Consciência/fisiologia , Estimulação Encefálica Profunda/métodos , Epilepsia/fisiopatologia , Epilepsia/terapia , Humanos
16.
Epilepsia ; 55(12): 1986-95, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25470216

RESUMO

OBJECTIVES: To study the incidence, spatial distribution, and signal characteristics of high frequency oscillations (HFOs) outside the epileptic network. METHODS: We included patients who underwent invasive evaluations at Yale Comprehensive Epilepsy Center from 2012 to 2013, had all major lobes sampled, and had localizable seizure onsets. Segments of non-rapid eye movement (NREM) sleep prior to the first seizure were analyzed. We implemented a semiautomated process to analyze oscillations with peak frequencies >80 Hz (ripples 80-250 Hz; fast ripples 250-500 Hz). A contact location was considered epileptic if it exhibited epileptiform discharges during the intracranial evaluation or was involved ictally within 5 s of seizure onset; otherwise it was considered nonepileptic. RESULTS: We analyzed recordings from 1,209 electrode contacts in seven patients. The nonepileptic contacts constituted 79.1% of the total number of contacts. Ripples constituted 99% of total detections. Eighty-two percent of all HFOs were seen in 45.2% of the nonepileptic contacts (82.1%, 47%, 34.6%, and 34% of the occipital, parietal, frontal, and temporal nonepileptic contacts, respectively). The following sublobes exhibited physiologic HFOs in all patients: Perirolandic, basal temporal, and occipital subregions. The ripples from nonepileptic sites had longer duration, higher amplitude, and lower peak frequency than ripples from epileptic sites. A high HFO rate (>1/min) was seen in 110 nonepileptic contacts, of which 68.2% were occipital. Fast ripples were less common, seen in nonepileptic parietooccipital regions only in two patients and in the epileptic mesial temporal structures. CONCLUSIONS: There is consistent occurrence of physiologic HFOs over vast areas of the neocortex outside the epileptic network. HFOs from nonepileptic regions were seen in the occipital lobes and in the perirolandic region in all patients. Although duration of ripples and peak frequency of HFOs are the most effective measures in distinguishing pathologic from physiologic events, there was significant overlap between the two groups.


Assuntos
Mapeamento Encefálico , Ondas Encefálicas/fisiologia , Encéfalo/fisiopatologia , Epilepsia/patologia , Epilepsia/fisiopatologia , Adolescente , Adulto , Relógios Biológicos/fisiologia , Criança , Eletroencefalografia , Feminino , Humanos , Masculino , Curva ROC , Adulto Jovem
17.
ScientificWorldJournal ; 2014: 349319, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25405219

RESUMO

Hemifacial spasm (HFS) is characterized by involuntary unilateral contractions of the muscles innervated by the ipsilateral facial nerve, usually starting around the eyes before progressing inferiorly to the cheek, mouth, and neck. Its prevalence is 9.8 per 100,000 persons with an average age of onset of 44 years. The accepted pathophysiology of HFS suggests that it is a disease process of the nerve root entry zone of the facial nerve. HFS can be divided into two types: primary and secondary. Primary HFS is triggered by vascular compression whereas secondary HFS comprises all other causes of facial nerve damage. Clinical examination and imaging modalities such as electromyography (EMG) and magnetic resonance imaging (MRI) are useful to differentiate HFS from other facial movement disorders and for intraoperative planning. The standard medical management for HFS is botulinum neurotoxin (BoNT) injections, which provides low-risk but limited symptomatic relief. The only curative treatment for HFS is microvascular decompression (MVD), a surgical intervention that provides lasting symptomatic relief by reducing compression of the facial nerve root. With a low rate of complications such as hearing loss, MVD remains the treatment of choice for HFS patients as intraoperative technique and monitoring continue to improve.


Assuntos
Descompressão Cirúrgica , Nervo Facial/cirurgia , Espasmo Hemifacial/cirurgia , Síndromes de Compressão Nervosa/cirurgia , Adulto , Idade de Início , Toxinas Botulínicas Tipo A/uso terapêutico , Eletromiografia , Nervo Facial/irrigação sanguínea , Nervo Facial/efeitos dos fármacos , Nervo Facial/fisiopatologia , Feminino , Espasmo Hemifacial/tratamento farmacológico , Espasmo Hemifacial/epidemiologia , Espasmo Hemifacial/fisiopatologia , Humanos , Imagem por Ressonância Magnética , Masculino , Microcirurgia/métodos , Pessoa de Meia-Idade , Síndromes de Compressão Nervosa/tratamento farmacológico , Síndromes de Compressão Nervosa/epidemiologia , Síndromes de Compressão Nervosa/fisiopatologia , Fármacos Neuromusculares/uso terapêutico
18.
Epilepsia ; 55(2): 289-95, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24417694

RESUMO

OBJECTIVE: Secondary generalization of seizures has devastating consequences for patient safety and quality of life. The aim of this intracranial electroencephalography (icEEG) study was to investigate the differences in onset and propagation patterns of temporal lobe seizures that remained focal versus those with secondary generalization, in order to better understand the mechanism of secondary generalization. METHODS: A total of 39 seizures were analyzed in nine patients who met the following criteria: (1) icEEG-video monitoring with at least one secondarily generalized tonic-clonic seizure (GTCS), (2) pathologically proven hippocampal sclerosis, and (3) no seizures for at least 1 year after anteromedial temporal lobe resection. Seizures were classified as focal or secondary generalized by behavioral analysis of video. Onset and propagation patterns were compared by analysis of icEEG. RESULTS: We obtained data from 22 focal seizures without generalization (FS), and 17 GTCS. Seizure-onset patterns did not differ between FS and GTCS, but there were differences in later propagation. All seizures started with low voltage fast activity, except for seven seizures in one patient (six FS, one GTCS), which started with sharply contoured theta activity. Fifteen of 39 seizures started from the hippocampus, and 24 seizures (including six seizures in a patient without hippocampal contacts) started from other medial temporal lobe areas. We observed involvement or more prominent activation of the posterior-lateral temporal regions in GTCS prior to propagation to the other cortical regions, versus FS, which had no involvement or less prominent activation of the posterior lateral temporal cortex. Occipital contacts were not involved at the time of clinical secondary generalization. SIGNIFICANCE: The posterior-lateral temporal cortex may serve as an important "gateway" controlling propagation of medial temporal lobe seizures to other cortical regions. Identifying the mechanisms of secondary generalization of focal seizures could lead to improved treatments to confine seizure spread.


Assuntos
Eletroencefalografia/métodos , Epilepsia Generalizada/fisiopatologia , Epilepsia do Lobo Temporal/fisiopatologia , Convulsões/fisiopatologia , Adulto , Epilepsias Parciais/diagnóstico , Epilepsias Parciais/fisiopatologia , Epilepsia Generalizada/diagnóstico , Epilepsia do Lobo Temporal/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Convulsões/diagnóstico , Gravação em Vídeo/métodos , Adulto Jovem
19.
J Neurointerv Surg ; 6(9): 684-90, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24319021

RESUMO

OBJECT: Seizures are a common presenting sign of intracranial arteriovenous malformations (AVMs). The object of this meta-analysis was to determine if the modality selected to treat AVMs affects the rate of seizure outcomes. METHODS: All published data describing seizure status as an outcome goal over the past 20 years were included in this study. Seizure outcomes following microsurgery (MS), endovascular embolization for cure (EVE), or stereotactic radiosurgery (SRS) were compared using a validated random effect logistic regression approach. RESULTS: 24 studies, with a total of 1157 patients, were analyzed. Overall, the microsurgical group had the best seizure control (p<0.01), with the relative predicted rates of seizure outcome as follows: MS 78.3% (95% CI 70.1% to 85.8%); SRS 62.8% (95% CI 55.0% to 70.0%); and EVE 49.3% (95% CI 32.1% to 66.6%). Patients in the SRS group who had complete obliteration of their AVMs achieved the highest rate of seizure control (85.2% (95% CI 79.1% to 91.2%); p<0.01). The development of new onset seizures occurred more frequently in patients undergoing EVE (39.4% (95% CI 8.1% to 67.8%)) compared with MS (9.1% (95% CI 5.0% to 13.1%)) and SRS (5.4% (95% CI 3.0% to 7.8%)) (p<0.3 and p<0.01, respectively). CONCLUSIONS: This is the first meta-analysis designed to study relative rates of seizure outcomes following the currently utilized AVM treatment modalities. In general, MS results in the highest proportion of seizure control. However, if SRS results in successful obliteration of the AVM, then this modality is the most effective in achieving seizure control.


Assuntos
Malformações Arteriovenosas Intracranianas/complicações , Malformações Arteriovenosas Intracranianas/cirurgia , Procedimentos Neurocirúrgicos/métodos , Convulsões/etiologia , Convulsões/cirurgia , Anticonvulsivantes/uso terapêutico , Embolização Terapêutica , Humanos , Microcirurgia/métodos , Radiocirurgia , Resultado do Tratamento
20.
Nat Protoc ; 8(5): 949-57, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23598445

RESUMO

Single-neuronal studies remain the gold standard for studying brain function. Here we describe a protocol for studying task-related single-neuronal activity in human subjects during neurosurgical procedures involving microelectrode recordings. This protocol has two phases: a preoperative phase and an intraoperative phase. During the preoperative phase, we discuss informed consent, equipment setup and behavioral testing. During the intraoperative phase, we discuss the procedure for microelectrode recordings. Because patients are often awake during these procedures, this protocol can be performed in conjunction with behavioral tasks for studying a variety of cognitive functions. We describe the protocol in detail and provide two examples of expected results. In addition, we discuss the potential difficulties and pitfalls related to intraoperative studies. This protocol takes ∼1.5 h to complete.


Assuntos
Encéfalo/fisiologia , Microeletrodos , Neurônios/fisiologia , Mapeamento Encefálico , Eletrofisiologia/métodos , Humanos , Procedimentos Neurocirúrgicos
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