Comparing Single-Photon Emission Computed Tomography (SPECT), Electroencephalography (EEG), and Magneto-encephalography (MEG) Seizure Localizations in Pediatric Cases of Laser Ablation.

Intractable epilepsy may have a more severe effect on children in comparison to adults because the motor, sensorial, and cognitive functions of children are still undergoing development. For this same reason, however, children maintain a greater potential for recovery from intractable epilepsy because of the remaining cerebral plasticity. Thus, after 2 unsuccessful antiepileptic medications, surgical intervention is recommended. Pre-surgical localization of the epileptogenic zone increases seizure-freedom post-surgery by 200% to 300%. Single-photon emission computed tomography (SPECT) is commonly used, with magneto-encephalography (MEG) and electroencephalography (EEG), to localize the epileptogenic zone, because it localizes cerebral blood flow. There is limited research in the efficacy of SPECT localization in pediatric pharmacoresistant epilepsy. Therefore, the objective of this study was to determine the efficacy of SPECT in it's ability to localize the epileptogenic zone in laser ablation cases of pediatric pharmacoresistant epilepsy. Out of 122 SPECTs conducted at Dell Children's Medical Center from July 2010 to January 2015, 12 underwent laser ablation. In the 12 cases of laser ablation, SPECT displayed more sensitivity and specificity than EEG and more specificity than MEG when held against the laser ablation outcomes. This study further proves that SPECT is efficacious in epileptogenic zone localization of pediatric pharmacoresistant epilepsy.

Benign rolandic epilepsy -- perhaps not so benign: use of magnetic source imaging as a predictor of outcome.

The purpose of this study was to evaluate children with benign rolandic epilepsy, a childhood epilepsy characterized by centrotemporal/rolandic spike-wave discharges with infrequent partial seizures that may secondarily generalize. Recently, some investigators have questioned whether benign rolandic epilepsy is indeed "benign" or whether long-term cognitive outcome may be adversely affected. We initiated an ongoing study to identify children with benign rolandic epilepsy. The children were evaluated in the Texas Comprehensive Epilepsy Program using outpatient or continuous video-electroencephalographic monitoring, brain magnetic resonance imaging, magnetoencephalography, and neuropsychological testing. Neuropsychological testing revealed fine motor dysfunction, visuomotor integration deficits, dyscalculia, and/or expressive language deficits in all of the 9 patients evaluated, reaffirming that benign rolandic epilepsy is not necessarily a benign disorder. Our study shows a high concordance of motor and cognitive deficits in benign rolandic epilepsy, as others have previously suggested. Furthermore, magnetic source imaging shows a higher resolution of dipole localization compared with conventional electroencephalography, which may ultimately improve prediction of deficits. This reaffirms that magnetoencephalography is a valuable diagnostic tool in the evaluation of children with benign rolandic epilepsy.

Corpus callosotomy: a palliative therapeutic technique may help identify resectable epileptogenic foci.

Corpus callosotomy has a long history as a palliative treatment for intractable epilepsy. Identification of a single epileptogenic zone is critical to performing successful resective surgery. We describe three patients in which corpus callosotomy allowed recognition of unapparent seizure foci, leading to subsequent successful resection. We retrospectively reviewed our epilepsy surgery database from 2003 to 2005 for children who had a prior callosotomy and were candidates for focal resection. All underwent magnetic resonance imaging and scalp video electroencephalograph monitoring, and two had magnetoencephalography, electrocorticography and/or intracranial video electroencephalograph monitoring. The children were 8 and 9 years old, and seizure onset varied from early infancy to early childhood. One child had a history of head trauma preceding seizure onset, one had a large intracerebral infarct and dysplastic cortex in the contralateral frontal lobe, and the other had an anterior temporal lobe resection without improvement in seizure frequency. After medical management failed, callosotomy was performed with the expectation of decreasing the seizure types affecting both hemispheres. Following transection of the callosal fibers, a single focus was recognized and resected, with resultant dramatic improvement in seizure control. In medically refractory epilepsy, where rapid secondary bisynchrony is suspected but the electroencephalograph is non-localizing, callosotomy should be considered as a means of treating generalized seizure types, but may also assist in identifying potentially operable seizure foci. Study limitations include its retrospective nature and cohort size. The findings, however, suggest the need for prospective, systematic, well-controlled studies of the use of corpus callostomy in this intractable patient population.

An MRI-compatible force sensor for measuring differential isometric precision grip force.

Investigating neural correlates of fine motor control in a magnetically sensitive environment requires special considerations in sensor design. Our application requires measurement of forefinger and thumb forces during precision grip in a relatively low (<; 20 N) force range. This work describes the design, characterization and performance evaluation of an MR-compatible precision grip sensor that independently measures forefinger and thumb forces. We selective laser sintered Nylon 12 into a flexure, measuring deformation using optic fibers which matches our finite element model simulation. We found that the device was capable of measuring forces within the desired range, with some hysteresis at higher frequencies as expected. We conclude that the device performs well compared to specifications.

Passive language mapping with magnetoencephalography in pediatric patients with epilepsy.

OBJECT: Functional mapping is important for determining surgical candidacy and also in epilepsy surgery planning. However, in young children and uncooperative patients, language mapping has been particularly challenging despite the advances in performing noninvasive functional studies. In this study the authors review a series of children with epilepsy who underwent language mapping with magnetoencephalography (MEG) while sedated or sleeping, to determine receptive language localization for presurgical evaluation. METHODS: The authors undertook a retrospective review of patients who underwent MEG between December 2007 and July 2009, and identified 15 individuals who underwent passive language testing as part of their presurgical evaluation because they were unable to participate in traditional language testing, such as Wada or functional MRI. Factors necessitating passive language testing included age and neurocognitive development. RESULTS: Three of the 15 patients were deemed candidates for epilepsy surgery based on the results from standard preoperative testing, including video electroencephalography, MRI, and passive receptive language testing using MEG technology. The MEG studies were used successfully to localize language in all 3 patients, creating opportunities for seizure freedom through surgery that would not otherwise have been available. All 3 patients then underwent resective epilepsy surgery without experiencing postoperative language deficits. CONCLUSIONS: This case series is the first to look at language mapping during sleep (passive language mapping) in which MEG was used and is the first to evaluate passive language testing in a patient population with intracranial pathological entities. This case series demonstrates that MEG can provide an alternative method for receptive language localization in patients with barriers to more traditional language testing, and in these 3 cases surgery was performed safely based on the results.

Time-locked brain activity associated with emotion: a pilot MEG study.

OBJECTIVE: To examine the time course of brain activation in response to emotionally evocative pictures. METHODS AND PROCEDURES: Regions of the brain involved in the processing of affective stimuli in response to picture sets rated unpleasant, pleasant and affectively neutral, as well as the order of activation of each region, were investigated using magnetoencephalography in 10 normal adult volunteers. RESULTS: Spatiotemporal maps were found consisting of two basic components. The first involving activation in the occipital and basal aspects of the temporal cortex- lasted, on average, 270 ms post-stimulus. The second component involving activation in the mesial temporal lobes (MTL) extended from 270 to 850 ms post-stimulus. After (serial) activating the mesial temporal lobe structures or simultaneous (parallel) to it, activation is also observed in the frontal structures. CONCLUSIONS: The temporal organization in the brain of an emotional stimulus requires the serial and alternating engagement of frontal and posterior cortices. It is suggested that lesions to the brain may disrupt this temporal course, altering the emotional response commonly observed in patients with brain injury.

EEG asymmetry, power, and temperament in children.

Measures of EEG spectral power, lateral asymmetry in the frontal and parietal areas, and social behavior with an examiner were analyzed on 166 children, 10 to 12 years old, who were participating in a longitudinal study of the temperamental contributions to social behavior. Loss of 8- to 13-Hz power (alpha band) on the right, compared with the left, frontal area (right frontal active) was most prevalent among children who were classified as high reactive at 4 months and were highly fearful at 14 and 21 months. Second, greater frontal power in the 14- to 30-Hz band (beta) at rest was correlated with the tendency to be right frontal active. Finally, spontaneous talkativeness with an unfamiliar examiner was associated with right frontal activation and high alpha power for boys, but with right frontal activation and high beta power for girls. Right frontal activation is most characteristic of children who begin life with a temperamental bias favoring high reactivity and who develop a fearful reaction to unfamiliar events in the second year of life.

One measure, one meaning: multiple measures, clearer meaning.

This paper tries to make three points. First, current constructs in personality and psychopathology are based on the restrictive evidence contained in self-reports. As a result, heterogeneous categories of individuals are assigned to the same category. Second, it is suggested that when different sources of evidence are included, theoretically distinct groups will be detected within the prior heterogeneous category. Third, the authors argue that physiological information has the potential to parse individuals with similar phenotypes on self-report data into distinct groups that reveal the temperamental origins of their phenotype.