Browsing by Author "Vinette, Sarah"
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- ItemOpen AccessArtifact reduction in long-term monitoring of cerebral hemodynamics using near-infrared spectroscopy(Society of Photo-optical Instrumentation Engineers, 2015-05-26) Vinette, Sarah; Dunn, Jeff; Slone, Edward; Federico, PaoloNear-infrared spectroscopy (NIRS) is a noninvasive neuroimaging technique used to assess cerebral hemodynamics. Its portability, ease of use, and relatively low operational cost lend itself well to the long-term monitoring of hemodynamic changes, such as those in epilepsy, where events are unpredictable. Long-term monitoring is associated with challenges including alterations in behaviors and motion that can result in artifacts. Five patients with epilepsy were assessed for interictal hemodynamic changes and alterations in behavior or motion. Based on this work, visual inspection was used to identify NIRS artifacts during a period of interest, specifically prior to seizures, in four patients. A motion artifact reduction algorithm (MARA, also known as the spline interpolation method) was tested on these data. Alterations in the NIRS measurements often occurred simultaneously with changes in motion and behavior. Occasionally, sharp shift artifacts were observed in the data. When artifacts appeared as sustained baseline shifts in the data, MARA reduced the standard deviation of the data and the appearance improved. We discussed motion and artifacts as challenges associated with longterm monitoring of cerebral hemodynamics in patients with epilepsy and our group’s approach to circumvent these challenges and improve the quality of the data collected.
- ItemOpen AccessInvestigation of the Pre-ictal State Using Near Infrared Spectroscopy and Functional Magnetic Resonance Imaging(2014-01-29) Vinette, Sarah; Federico, PaoloThe unpredictability of seizures impacts the quality of life of those with epilepsy. Previous studies have reported changes in cerebral hemodynamics prior to the onset of seizures, providing evidence of the existence of a pre-ictal state. In this thesis, near infrared spectroscopy (NIRS) and functional magnetic resonance imaging (fMRI) techniques were developed to characterize the variation in cerebral hemodynamics prior to seizures, in patients with focal epilepsy. The findings indicate that there are changes in cerebral hemodynamics within both hemispheres minutes prior to seizures. These results provide encouraging evidence that, with further technical improvements in the specificity of these techniques, the identification of such changes could allow sufficient time for measures to be taken to prevent seizure onset, thereby reducing the likelihood of seizures and improving the quality of life of those with epilepsy.