Browsing by Author "Cash, Sydney S."

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    Brain-responsive neurostimulation in patients with medically intractable mesial temporal lobe epilepsy
    (Wiley, 2017-06) Geller, Eric B.; Skarpass, Tara L.; Gross, Robert E.; Goodman, Robert R.; Barkley, Gregory L.; Bazil, Carl W.; Berg, Michael J.; Bergey, Gregory K.; Cash, Sydney S.; Cole, Andrew J.; Duckrow, Robert B.; Edwards, Jonathan C.; Eisenschenk, Stephan; Fessler, James; Fountain, Nathan B.; Goldman, Alicia M.; Gwinn, Ryder P.; Heck, Christianne; Herekar, Aamar; Hirsch, Lawrence J.; Jobst, Barbara C.; King-Stephens, David; Labar, Douglas R.; Leiphart, James W.; Marsh, W. Richard; Meador, Kimford J.; Mizrahi, Eli M.; Murro, Anthony M.; Nair, Dileep R.; Noe, Katherine H.; Park, Yong D.; Rutecki, Paul A.; Salanova, Vicenta; Sheth, Raj D.; Shields, Donald C.; Skidmore, Christopher; Smith, Michael C.; Spencer, David C.; Srinivasan, Shraddha; Tatum, William; Van Ness, Paul C.; Vossler, David G.; Wharen, Robert E., Jr.; Worrell, Gregory A.; Yoshor, Daniel; Zimmerman, Richard S.; Cicora, Kathy; Sun, Felice T.; Morrell, Martha J.; Neurology, School of Medicine
    Objective Evaluate the seizure-reduction response and safety of mesial temporal lobe (MTL) brain-responsive stimulation in adults with medically intractable partial-onset seizures of mesial temporal lobe origin. Methods Subjects with mesial temporal lobe epilepsy (MTLE) were identified from prospective clinical trials of a brain-responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2–6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events. Results There were 111 subjects with MTLE; 72% of subjects had bilateral MTL onsets and 28% had unilateral onsets. Subjects had one to four leads placed; only two leads could be connected to the device. Seventy-six subjects had depth leads only, 29 had both depth and strip leads, and 6 had only strip leads. The mean follow-up was 6.1 ± (standard deviation) 2.2 years. The median percent seizure reduction was 70% (last observation carried forward). Twenty-nine percent of subjects experienced at least one seizure-free period of 6 months or longer, and 15% experienced at least one seizure-free period of 1 year or longer. There was no difference in seizure reduction in subjects with and without mesial temporal sclerosis (MTS), bilateral MTL onsets, prior resection, prior intracranial monitoring, and prior vagus nerve stimulation. In addition, seizure reduction was not dependent on the location of depth leads relative to the hippocampus. The most frequent serious device-related adverse event was soft tissue implant-site infection (overall rate, including events categorized as device-related, uncertain, or not device-related: 0.03 per implant year, which is not greater than with other neurostimulation devices). Significance Brain-responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including patients with unilateral or bilateral MTLE who are not candidates for temporal lobectomy or who have failed a prior MTL resection.
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    Brain-responsive neurostimulation in patients with medically intractable seizures arising from eloquent and other neocortical areas
    (Wiley, 2017-06) Jobst, Barbara C.; Kapur, Ritu; Barkley, Gregory L.; Bazil, Carl W.; Berg, Michel J.; Bergey, Gregory K.; Boggs, Jane G.; Cash, Sydney S.; Cole, Andrew J.; Duchowny, Michael S.; Duckrow, Robert B.; Edwards, Jonathan C.; Eisenschenk, Stephan; Fessler, A. James; Fountain, Nathan B.; Geller, Eric B.; Goldman, Alica M.; Goodman, Robert R.; Gross, Robert E.; Gwinn, Ryder P.; Heck, Christianne; Herekar, Aamr A.; Hirsch, Lawrence J.; King-Stephens, David; Labar, Douglas R.; Marsh, W. R.; Meador, Kimford J.; Miller, Ian; Mizrahi, Eli M.; Murro, Anthony M.; Nair, Dileep R.; Noe, Katherine H.; Olejniczak, Piotr W.; Park, Yong D.; Rutecki, Paul; Salanova, Vicenta; Sheth, Raj D.; Skidmore, Christopher; Smith, Michael C.; Spencer, David C.; Srinivasan, Shraddha; Tatum, William; Van Ness, Paul; Vossler, David G.; Wharen, Robert E., Jr.; Worrell, Gregory A.; Yoshor, Daniel; Zimmerman, Richard S.; Skarpass, Tara L.; Morrell, Martha J.; Neurology, School of Medicine
    Objective Evaluate the seizure-reduction response and safety of brain-responsive stimulation in adults with medically intractable partial-onset seizures of neocortical origin. Methods Patients with partial seizures of neocortical origin were identified from prospective clinical trials of a brain-responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2–6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events. Additional analyses considered safety and seizure reduction according to lobe and functional area (e.g., eloquent cortex) of seizure onset. Results There were 126 patients with seizures of neocortical onset. The average follow-up was 6.1 implant years. The median percent seizure reduction was 70% in patients with frontal and parietal seizure onsets, 58% in those with temporal neocortical onsets, and 51% in those with multilobar onsets (last observation carried forward [LOCF] analysis). Twenty-six percent of patients experienced at least one seizure-free period of 6 months or longer and 14% experienced at least one seizure-free period of 1 year or longer. Patients with lesions on magnetic resonance imaging (MRI; 77% reduction, LOCF) and those with normal MRI findings (45% reduction, LOCF) benefitted, although the treatment response was more robust in patients with an MRI lesion (p = 0.02, generalized estimating equation [GEE]). There were no differences in the seizure reduction in patients with and without prior epilepsy surgery or vagus nerve stimulation. Stimulation parameters used for treatment did not cause acute or chronic neurologic deficits, even in eloquent cortical areas. The rates of infection (0.017 per patient implant year) and perioperative hemorrhage (0.8%) were not greater than with other neurostimulation devices. Significance Brain-responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including adults with seizures of neocortical onset, and those with onsets from eloquent cortex.
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    Delay Differential Analysis of Seizures in Multichannel Electrocorticography Data
    (MIT, 2017-12) Lainscsek, Claudia; Weyhenmeyer, Jonathan; Cash, Sydney S.; Sejnowski, Terrence J.; Neurological Surgery, School of Medicine
    High-density electrocorticogram (ECoG) electrodes are capable of recording neurophysiological data with high temporal resolution with wide spatial coverage. These recordings are a window to understanding how the human brain processes information and subsequently behaves in healthy and pathologic states. Here, we describe and implement delay differential analysis (DDA) for the characterization of ECoG data obtained from human patients with intractable epilepsy. DDA is a time-domain analysis framework based on embedding theory in nonlinear dynamics that reveals the nonlinear invariant properties of an unknown dynamical system. The DDA embedding serves as a low-dimensional nonlinear dynamical basis onto which the data are mapped. This greatly reduces the risk of overfitting and improves the method's ability to fit classes of data. Since the basis is built on the dynamical structure of the data, preprocessing of the data (e.g., filtering) is not necessary. We performed a large-scale search for a DDA model that best fit ECoG recordings using a genetic algorithm to qualitatively discriminate between different cortical states and epileptic events for a set of 13 patients. A single DDA model with only three polynomial terms was identified. Singular value decomposition across the feature space of the model revealed both global and local dynamics that could differentiate electrographic and electroclinical seizures and provided insights into highly localized seizure onsets and diffuse seizure terminations. Other common ECoG features such as interictal periods, artifacts, and exogenous stimuli were also analyzed with DDA. This novel framework for signal processing of seizure information demonstrates an ability to reveal unique characteristics of the underlying dynamics of the seizure and may be useful in better understanding, detecting, and maybe even predicting seizures.