Spinal dural arteriovenous fistula in a child: a rare presentation.

Spinal dural arteriovenous fistula (AVF) is an abnormal shunting between the segmental artery and radicular vein adjacent to the dural root sleeve in the spine. This is the most common vascular malformation of the spinal cord and is a rare but treatable cause of para or quadriplegia. It most commonly occurs in elderly men and often affects the thoracolumbar region. These patients clinically present with progressive myelopathies, and other autonomic symptoms (e.g., bladder and bowel dysfunction) subsequently in the later course of the disease. Computed tomography angiography and magnetic resonance imaging remain the modality for initial evaluation. Herein, we present a rare case of spinal dural AVF in a child along with a review of imaging modalities. To the best of our knowledge, there are few case reports of this condition in a paediatric age group.

Functional MRI and direct cortical stimulation: Prediction of postoperative language decline.

OBJECTIVE: To assess the ability of functional MRI (fMRI) to predict postoperative language decline compared to direct cortical stimulation (DCS) in epilepsy surgery patients. METHODS: In this prospective case series, 17 patients with drug-resistant epilepsy had intracranial monitoring and resection from 2012 to 2016 with 1-year follow-up. All patients completed preoperative language fMRI, mapping with DCS of subdural electrodes, pre- and postoperative neuropsychological testing for language function, and resection. Changes in language function before and after surgery were assessed. fMRI activation and DCS electrodes in the resection were evaluated as potential predictors of language decline. RESULTS: Four of 17 patients (12 female; median [range] age, 43 [23-59] years) experienced postoperative language decline 1 year after surgery. Two of 4 patients had overlap of fMRI activation, language-positive electrodes in basal temporal regions (within 1 cm), and resection. Two had overlap between resection volume and fMRI activation, but not DCS. fMRI demonstrated 100% sensitivity and 46% specificity for outcome compared to DCS (50% and 85%, respectively). When fMRI and DCS language findings were concordant, the combined tests showed 100% sensitivity and 75% specificity for language outcome. Seizure-onset age, resection side, type, volume, or 1 year seizure outcome did not predict language decline. SIGNIFICANCE: Language localization overlap of fMRI and direct cortical stimulation in the resection influences postoperative language performance. Our preliminary study suggests that fMRI may be more sensitive and less specific than direct cortical stimulation. Together they may predict outcome better than either test alone.

Using network analysis to localize the epileptogenic zone from invasive EEG recordings in intractable focal epilepsy.

Treatment of medically intractable focal epilepsy (MIFE) by surgical resection of the epileptogenic zone (EZ) is often effective provided the EZ can be reliably identified. Even with the use of invasive recordings, the clinical differentiation between the EZ and normal brain areas can be quite challenging, mainly in patients without MRI detectable lesions. Consequently, despite relatively large brain regions being removed, surgical success rates barely reach 60-65%. Such variable and unfavorable outcomes associated with high morbidity rates are often caused by imprecise and/or inaccurate EZ localization. We developed a localization algorithm that uses network-based data analytics to process invasive EEG recordings. This network algorithm analyzes the centrality signatures of every contact electrode within the recording network and characterizes contacts into susceptible EZ based on the centrality trends over time. The algorithm was tested in a retrospective study that included 42 patients from four epilepsy centers. Our algorithm had higher agreement with EZ regions identified by clinicians for patients with successful surgical outcomes and less agreement for patients with failed outcomes. These findings suggest that network analytics and a network systems perspective of epilepsy may be useful in assisting clinicians in more accurately localizing the EZ.

Language functional MRI and direct cortical stimulation in epilepsy preoperative planning.

OBJECTIVE: Presurgical language assessment can help minimize damage to eloquent cortex during resective epilepsy surgery. Two methods for presurgical language mapping are functional MRI (fMRI) and direct cortical stimulation (DCS) of implanted subdural electrodes. We compared fMRI results to DCS to help optimize noninvasive language localization and assess its validity. METHODS: We studied 19 patients referred for presurgical evaluation of drug-resistant epilepsy. Patients completed four language tasks during preoperative fMRI. After subdural electrode implantation, we used DCS to localize language areas. For each stimulation site, we determined whether language positive electrode pairs intersected with significant fMRI activity clusters for language tasks. RESULTS: Sensitivity and specificity depended on electrode region of interest radii and statistical thresholding. For patients with at least one language positive stimulation site, an auditory description decision task provided the best trade-off between sensitivity and specificity. For patients with no language positive stimulation sites, fMRI was a dependable method of excluding eloquent language processing. INTERPRETATION: Language fMRI is an effective tool for determining language lateralization before electrode implantation and is especially useful for excluding unexpected critical language areas. It can help guide subdural electrode implantation and narrow the search for eloquent cortical areas by DCS. Ann Neurol 2017;81:526-537.