Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society
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J Clin Neurophysiol · Aug 2007
ReviewElectrophysiologic monitoring during surgery to repair the thoraco-abdominal aorta.
Prevention of paraplegia during the repair of thoraco-abdominal aortic aneurysms and dissections present a substantial challenge to the operative team. The value of intraoperative electrophysiological monitoring (IOM) is to identify spinal cord ischemia that occurs during the procedure and guide the intraoperative management to reduce the risks of paralysis. The usefulness of IOM techniques requires an understanding of spinal cord blood flow and the spinal cord physiology, the surgical technique and their interaction. This paper will integrate these factors to review the laboratory and clinical experience with somatosensory evoked responses (SSEP) and motor evoked potentials (MEP) during thoraco-abdominal aorta surgery.
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J Clin Neurophysiol · Aug 2006
ReviewValue and limitations of seizure semiology in localizing seizure onset.
Seizure semiology has been the foundation of clinical diagnosis of seizure disorders. This article discusses the value and the limitations of behavioral features of seizure episodes in localizing seizure onset. Studies have shown that some semiologic features of seizures are highly accurate in the hemispheric lateralization and lobar localization of seizures. ⋯ Many semiologic features of seizures of adults are often missing in seizures of children. Seizure semiology should be analyzed and integrated with EEG and neuroimaging data to localize the seizure focus. A sample of the recorded seizures should be shown to the patient's relatives or friends to verify that it is representative of habitual seizures.
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J Clin Neurophysiol · Apr 2005
ReviewMultimodal brain monitoring in the neurological intensive care unit: where does continuous EEG fit in?
Continuous EEG (cEEG) is a vital component of patient monitoring in the neurologic intensive care unit, allowing the intensivist to diagnose nonconvulsive seizure activity. Though still in its infancy, Fourier-transformed cEEG data are also increasingly being used in ICUs to monitor global cerebral activity and cortical function. In conjunction with other components of multimodality neurologic monitoring, including intracranial pressure, cerebral blood flow, brain tissue oxygen tension monitoring, transcranial Doppler, and microdialysis monitoring, cEEG provides unique data regarding the electrical activity of the brain. The main challenge for clinicians and researchers will be to understand how these different aspects of multimodality monitoring relate to each other, and how physiologic variables such as blood pressure, osmolality, and temperature can be manipulated to optimize cerebral function and tissue survival in the setting of acute injury.
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J Clin Neurophysiol · Apr 2005
ReviewContinuous EEG monitoring in patients with subarachnoid hemorrhage.
Patients with subarachnoid hemorrhage (SAH) are at risk for seizures and delayed cerebral ischemia, both of which can be detected with continuous EEG monitoring (cEEG). Ischemia can be detected with EEG at a reversible stage. CEEG may be most useful in patients with poor grade SAH, as the neurological exam is of limited utility in these stuporous or comatose patients. ⋯ Applying quantitative analysis to the cEEG (relative alpha variability, post-stimulation alpha/delta ratio) allows reliable detection of ischemia from vasospasm, with EEG changes often preceding changes in the clinical exam and other non-continuous monitoring techniques by up to two days. In patients at risk for developing vasospasm, cEEG monitoring, preferably with quantitative EEG analysis, should be started as early as possible and carried out for up to 14 days after the SAH. CEEG findings may lead to therapeutic (e.g., antiepileptic medication, hypertensive therapy, angioplasty) or additional diagnostic interventions such as angiography, CT or MRI.
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J Clin Neurophysiol · Apr 2005
ReviewWhich EEG patterns warrant treatment in the critically ill? Reviewing the evidence for treatment of periodic epileptiform discharges and related patterns.
Continuous electroencephalographic monitoring in critically ill patients has improved detection of nonconvulsive seizures and periodic discharges, but when and how aggressively to treat these electrographic patterns is unclear. A review of the literature was conducted to understand the nature of periodic discharges and the strength of the data on which management recommendations have been based. ⋯ This spectrum suggests a need to consider these phenomena along a continuum between interictal and ictal, but more important clinically is the need to consider the likelihood of neuronal injury from each type of discharge in a given clinical setting. Recommendations for treatment are given, and a modification to current criteria for the diagnosis of nonconvulsive seizures is suggested.