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Purpose: Post-operative seizure rates after endoscopic third ventriculostomy (ETV) are not definitively known. We analyzed our institution's experience for all causes of hydrocephalus in pediatric patients undergoing ETV to determine rates of post-ETV seizure. Methods: A retrospective review of institutional pediatric patients undergoing ETV from May 2014 to December 2018. Included were < 21 years, with 1-year follow-up. Exclusion criteria included ventriculoperitoneal shunts (VPS) prior to ETV, VPS within 7 days post-ETV, and prior seizure disorder. Data included age, gender, diagnosis, early post-operative seizure (within 7 days post-ETV), late post-operative seizures (after first 7 days and within first year post-ETV), concomitant choroid plexus cauterization (CPC), VPS conversion within 1 year, and administration of prophylactic antiepileptics. Results: Sixty of 81 ETV cases were included; 41% underwent concomitant CPC. Of these, 53% (n = 32) were male, 46% (n = 28) female, averaging 5.8 years, with the most common diagnosis neoplasm-related obstructive hydrocephalus (38.3%, n = 23). Early post-operative seizure occurred in 6.7% (n = 4); late post-operative seizure occurred in 8.3% (n = 5). Late post-operative seizures were higher in patients experiencing early post-operative seizure versus those without (75% vs 3.7%, p = 0.003). Late post-operative seizure occurred in 13.6% (n = 3 patients) requiring VPS versus 5.3% (n = 2 patients) with successful ETV (p = 0.36). Rates did not correlate with pathology. No patients received prophylactic antiepileptics prior to surgery or exhibiting a seizure. Conclusions: Patients with early post-operative seizures have an increased likelihood of developing late post-operative seizures. Pediatric ETV patients may have a lower rate of both early and late post-operative seizure; underlying pathology may influence these rates. [ABSTRACT FROM AUTHOR]

During active movement the electric potentials measured from the surface of the motor cortex exhibit consistent modulation, revealing two distinguishable processes in the power spectrum. At frequencies <40 Hz, narrow-band power decreases occur with movement over widely distributed cortical areas, while at higher frequencies there are spatially more focal power increases. These high-frequency changes have commonly been assumed to reflect synchronous rhythms, analogous to lower-frequency phenomena, but it has recently been proposed that they reflect a broad-band spectral change across the entire spectrum, which could be obscured by synchronous rhythms at low frequencies. In 10 human subjects performing a finger movement task, we demonstrate that a principal component type of decomposition can naively separate low-frequency narrow-band rhythms from an asynchronous, broad-spectral, change at all frequencies between 5 and 200 Hz. This broad-spectral change exhibited spatially discrete representation for individual fingers and reproduced the temporal movement trajectories of different individual fingers. [ABSTRACT FROM AUTHOR]

Two methods of quantifying hemispheric language dominance (HLD) in neurosurgical patients are compared: (1) an average magnitudes (AM) method, which is a calculation of the average signal intensity variation in regions of interest for each patient that were predefined in a group analysis for each task, and (2) a lateralization indices (LI) method, which is based on the number of activated pixels in regions of interest predefined in each individual patient. Four language tasks [a living/nonliving (LNL) judgment, word stem completion (WSC), semantic associate (SA) and a phonological associate (PA) task] were compared with “gold standard” measures such as the Wada test or electrocortical stimulation. Results showed that the LI method was more accurate (73% agreement with gold standard methods) than the AM method (only 40% agreement) across tasks and subjects. Furthermore, by varying the threshold used for determining laterality, the ability of functional magnetic resonance imaging (fMRI) to predict HLD was influenced for the AM method, whereas the LI method was relatively unaffected by changing the threshold. Using the LI method, the SA task was the most accurate for quantifying HLD (100% agreement with gold standard methods) with respect to the other three language tasks (80% accuracy for WSC, 65% for the LNL and 63% for phonological task). Depending on the method and the task, fMRI may be a promising tool for assessing HLD in neurosurgical patients. [ABSTRACT FROM AUTHOR]

Neuroimaging studies have suggested that specific regions of the frontal and medial temporal cortex are engaged during memory formation. Further, there is specialization across these regions such that verbal materials appear to preferentially engage the left regions while nonverbal materials primarily engage the right regions. An open question, however, has been to what extent frontal regions contribute to successful memory formation. The present study investigates this question using a reversible lesion technique known as the Wada test. Patients memorized words and unfamiliar faces while portions of their left and right hemispheres were temporarily anesthetized with sodium amytal. Subsequent memory tests revealed that faces were remembered better than words following left-hemisphere anesthesia, whereas words were remembered better than faces following right-hemisphere anesthesia. Importantly, inspection of the circulation affected by the amytal further suggests that these memory impairments did not result from direct anesthetization of the medial temporal regions. Taken in the context of the imaging findings, these results suggest that frontal regions may also contribute to memory formation in normal performance. [ABSTRACT FROM AUTHOR]

We report a patient with hydrocephalus who developed levodopa responsive parkinsonism and severe bradyphrenia associated with shunt malfunction and revision. Magnetic resonance imaging revealed periaqueductal edema involving medial substantia nigra. [18F]dopa positron emission tomography demonstrated reduced uptake in the caudate and putamen with relative sparing of the posterior putamen. Hydrocephalus associated with shunt malfunction can cause a distinct parkinsonian syndrome with greater dysfunction of projections from the medial substantia nigra to anterior striatum than in idiopathic Parkinson's disease. [ABSTRACT FROM AUTHOR]