Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society
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J Clin Neurophysiol · Dec 2013
Simultaneous direct cortical motor evoked potential monitoring and subcortical mapping for motor pathway preservation during brain tumor surgery: is it useful?
The warning-sign hierarchy between quantitative subcortical motor mapping and continuous motor evoked potential monitoring during resection of supratentorial brain tumors: clinical article.Seidel K, Beck J, Steiglitz L, Schucht P, Raabe A.J Neurosurg 2013; 118:287-296. ⋯ Mapping should primarily guide tumor resection adjacent to the CST. Direct cortical stimulation-motor evoked potential is a useful predictor of deficits, but its value as a warning sign is limited because signal alterations were reversible in only approximately 60% of the present cases and irreversibility is a post hoc definition. The true safe mapping MT is lower than previously thought. The authors postulate a mapping MT of 1 mA or less where irreversible DCS-MEP changes and motor deficits regularly occur. Therefore, they recommend stopping tumor resection at an MT of 2 mA at the latest. The limited spatial and temporal coverage of contemporary mapping may increase error and may contribute to false, higher MTs.
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This article serves to (1) review the relationship of the terms "delirium" and "encephalopathy," (2) describe delirium as defined in current diagnostic systems, (3) summarize the epidemiology and theories of pathogenesis, (4) review clinical diagnostic approaches, and (5) highlight the history using EEG in the study of delirium in the psychiatric literature. Delirium is an important medical syndrome with significant implications; there is continued need for better physiologic measures of the underlying brain dysfunction.
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This review will discuss several intracranial infections and sepsis-associated encephalopathy. Intracranial infections and inflammation of interest to the neurologist and EEG technicians include viral and autoimmune encephalitides; bacterial, fungal, and other meningitides; cerebritis; and brain abscess and subdural empyema. Sepsis-associated encephalopathy refers to a diffuse brain dysfunction secondary to infection that is principally located outside of the central nervous system. ⋯ It probably involves a number of mechanisms that are not mutually exclusive and likely vary from patient to patient. Morbidity and mortality are directly related to the severity of SAE. The earliest features of SAE are delirium and mild EEG slowing; it is crucial to recognize these early features and to search for and treat the underlying infection promptly to reduce mortality and morbidity.
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J Clin Neurophysiol · Aug 2013
Comparative StudyDensity spectral array for seizure identification in critically ill children.
We evaluated the validity and interrater reliability of encephalographer interpretation of color density spectral array EEG for seizure identification was evaluated in critically ill children and explored predictors of accurate seizure identification. ⋯ Color density spectral array may be a useful screening tool for seizure identification by encephalographers, but it does not identify all seizures and false positives occur.
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J Clin Neurophysiol · Aug 2013
Comparative StudyPreservation of motor evoked potentials under anesthesia in children with spinal muscular atrophy type II undergoing spinal deformity surgery.
Spinal muscular atrophy is a progressive condition in which movement is gradually lost as a result of the loss of spinal motor neurons. Individuals with this condition may require surgical correction of a secondary scoliosis. Motor evoked potentials were recorded using transcranial electrical stimulation in four such individuals undergoing surgery. ⋯ Motor evoked potentials were recordable in both upper and lower limb muscles, with similar stimulation parameters to control subjects undergoing surgery for idiopathic scoliosis. The amplitudes of the motor evoked potentials were similar to those in control subjects, although the latencies were shorter reflective of the smaller stature of the spinal muscular atrophy patients. The relative preservation of the motor evoked potentials despite the patients' poor voluntary motor control suggests that there is a selective preservation of the motor neurons mediating the motor evoked potential in spinal muscular atrophy and a maintenance of the conduction velocities of the corticospinal tract.