Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society
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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.
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J Clin Neurophysiol · Apr 2005
ReviewContinuous EEG monitoring for the detection of seizures in traumatic brain injury, infarction, and intracerebral hemorrhage: "to detect and protect".
Brain injury results in a primary pathophysiologic response that enables the brain to have seizures. Seizures occur frequently after traumatic and nontraumatic intracerebral bleeding. ⋯ Seizures after brain injury worsen clinical outcome and need to be treated. In summary, cEEG is a valuable clinical instrument "to detect and protect," i.e., to detect seizures and protect the brain from seizure-related injury in critically ill patients, whose brains are often in a particularly vulnerable state.
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J Clin Neurophysiol · Jan 2005
Comparative Study Clinical TrialHow salient is the silent period? The role of the silent period in the prognosis of upper extremity motor recovery after severe stroke.
Transcranial magnetic stimulation (TMS) has been successful in the prediction of motor recovery in acute stroke patients with initially severe paresis or paralysis of the upper extremity. Motor evoked potentials (MEP) appear to have a high specificity but a rather low sensitivity with regard to motor recovery. The silent period (SP) has been proposed as an additional factor to the MEP for predicting motor recovery that might optimize the sensitivity of TMS. ⋯ This review emphasizes the significance of the SP in predicting poststroke motor recovery and spasticity. Although the relation among the SP, recovery-related intracortical phenomena, and spasticity remains unclear, a neurophysiologic model underlying the SP is discussed. However, more research is needed on the value of the SP for predicting poststroke spasticity.
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J Clin Neurophysiol · Nov 2004
Comparative Study Clinical TrialClinical versus electrophysiological assessment of dysautonomia in obstructive sleep apnea syndrome.
To assess the autonomic system in obstructive sleep apnea syndrome (OSAS), the sympathetic skin response (SSR) and the R-R interval variation (RRIV) tests were studied in 34 OSAS patients and in 32 healthy controls. The aim of the study was to evaluate the sympathetic and parasympathetic system function in OSAS, to define the pattern of autonomic abnormalities found in SSR and RRIV in patients, and to analyze the usefulness of both tests in paraclinical assessment of the dysautonomia, compared with clinical symptoms and signs of autonomic nervous system involvement. The correlations between both autonomic tests results were also studied. ⋯ The clinical studies results (according to the Autonomic Symptoms Questionnaire) were related to the SSR results (p < 0.05 on chi and Fisher exact test). According to these results, SSR and RRIV are simple paraclinical electrophysiologic tests that confirm clinical dysautonomia. They may be useful as screening tests for assessment of dysautonomia in OSAS.