Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society
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J Clin Neurophysiol · Jul 1999
Sources of movement-related cortical potentials derived from foot, finger, and mouth movements.
Movement-related cortical potentials (MRCPs) register brain electrical activity before and during movement execution. In an attempt to delineate the components of MRCPs that reflect common sources to various movements and that are movement-specific, simple self-paced voluntary foot, finger, and mouth movements were studied. MRCPs were recorded in eight healthy volunteers with 30 electrodes placed on the scalp. ⋯ Multiple equivalent dipole models developed in this study implied the activity originating in corresponding brain areas as previously detected by positron emission tomography or functional magnetic resonance imaging. However, MRCPs provided additional information regarding the temporal evolution of the brain activity related to the execution of voluntary movements. Thus, the concurrent use of MRCPs and other imaging techniques may provide complementary information not easily obtained by the other imaging techniques themselves.
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J Clin Neurophysiol · Jul 1999
ReviewAssessing the outcomes in patients with nonconvulsive status epilepticus: nonconvulsive status epilepticus is underdiagnosed, potentially overtreated, and confounded by comorbidity.
Nonconvulsive status epilepticus (NCSE) is characterized by behavioral or cognitive change from baseline for at least 30 minutes with EEG evidence of seizures. Categorized into complex partial status epilepticus (with lateralized seizures), and generalized nonconvulsive status epilepticus (bilateral diffuse synchronous seizures), there is debate regarding the diagnosis and morbidity of NCSE. Because EEG is needed for diagnosis, only a high index of suspicion leads to a request for the study, whereas EEG is often unavailable after hours or on weekends. ⋯ Regarding treatment, comatose NCSE patients treated with benzodiazepines may worsen, whereas generalized nonconvulsive status epilepticus patients may suffer iatrogenically from aggressive treatment (hypotension and respiratory depression) necessitating balancing the potential neurologic morbidity of NCSE against the possible morbidity of IV antiepileptic drugs. A high index of suspicion is needed to initiate EEG studies. Better stratification of level of consciousness will be needed to distinguish among morbidity due to underlying conditions, treatment, and the effects of status epilepticus, proper.
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J Clin Neurophysiol · Jul 1999
ReviewEpidemiology and evidence for morbidity of nonconvulsive status epilepticus.
Convulsive status epilepticus (SE) is convincingly related to serious morbidity and mortality and well recognized as a medical emergency, but prompt diagnosis and treatment of patients with nonconvulsive status epilepticus (NCSE) is often not emphasized because its consequences are thought to be benign. Nonconvulsive status epilepticus has been considered a relatively benign entity because it does not produce the adverse systemic consequences of convulsive status epilepticus, such as hyperthermia, acidosis, hyperkalemia, pulmonary compromise, or cardiovascular collapse. However, recent reports indicate that NCSE is not so benign. ⋯ Other similar epileptiform encephalopathies such as "subclinical," "electroencephalographic," "nontonic-clonic," and "subtle" SE have not been as well studied as NCSE but pose similar issues. Early diagnosis and aggressive intervention have proven the best means of averting adverse outcomes in patients with convulsive SE. The diagnosis and treatment of NCSE, particularly complex partial status epilepticus, merit similar emphasis and attention.