Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society
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J Clin Neurophysiol · Aug 2011
Comparative StudyBenefit of repeat multiple sleep latency testing in confirming a possible narcolepsy diagnosis.
The clinical diagnosis of narcolepsy is usually uncomplicated in the presence of cataplexy. Objective testing is more important in ambiguous disease. The gold-standard objective test in these cases is the multiple sleep latency test (MSLT). Repeat testing can be burdensome but is reasonable when faced with a diagnostic dilemma. However, there is limited evidence to support this approach. In this study, we assessed the diagnostic utility of a repeat MSLT in patients suspected of narcolepsy whose first MSLT result was nonconfirmatory. ⋯ We demonstrate that a repeat MSLT confirmed the diagnosis of narcolepsy in 20% of patients whose results had been nonconfirmatory on a first MSLT. This study provides support for a repeat MSLT in cases where clinical suspicion for narcolepsy is high despite an ambiguous first test.
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J Clin Neurophysiol · Jun 2011
Clinical TrialAuditory evoked potential P50 as a predictor of neurologic outcome in resuscitated cardiac arrest patients.
In general, a prediction of neurologic outcome with respect to the resuscitated cardiac arrest patients has been performed by the auditory brainstem response and somatic evoked potential. The auditory brainstem response and somatic evoked potential are known as the predictors that correspond to neurologically poor outcome. None of the methods have been established to access neurologically good outcome. ⋯ It was found that the presence of the P50 at the early stage from the onset (days 5 ± 1.20) indicates good neurologic outcome, while the absence of the P50 implies poor prognosis. As to the auditory sensory gating of the P50, almost no reduction response to the second stimulus was observed. As a consequence, the evaluation of the P50 in resuscitated cardiac arrest patients would have a possibility to predict neurologically good outcome.
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Artifacts may be obtained during routine recording but are more common in special care units (SCUs) outside of the EEG laboratory, where complex electrical currents are present that create a "hostile" environment. Special care units include the epilepsy monitoring unit, neurologic intensive care unit, and operating room, where artifact is present in virtually every recording, increasing with prolonged use. ⋯ The artifacts encountered in special care units during continuous EEG are becoming more complex and may have adverse therapeutic implications. Our knowledge of artifact needs to parallel our growth in technology to avoid the pitfalls that may be incurred during visual analysis of the EEG.
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J Clin Neurophysiol · Jun 2011
Association between neuropathic pain and A-waves in leprosy patients with type 1 and 2 reactions.
Neuropathic pain (NP) is a well-recognized feature of leprosy neuropathy. However, the diagnosis of NP is difficult using only clinical criteria. In the study reported here, by means of conventional nerve conduction studies, the authors sought for an association between long-latency responses and NP complaints in leprosy patients with type 1 and 2 reactions. ⋯ In conclusion, the presence of A-waves correlates well with pain complaints of neuropathic characteristics in leprosy patients, especially in those with type 2 reaction. Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting. Further studies using specific tools for small-fiber assessment are warranted to confirm our findings.
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J Clin Neurophysiol · Jun 2011
EEG patterns and imaging correlations in encephalopathy: encephalopathy part II.
The EEG patterns seen with encephalopathies can be correlated to cerebral imaging findings including head computerized tomography and MRI. Background slowing without slow-wave intrusion is seen with acute and chronic cortical impairments that spare subcortical white matter. ⋯ More specific syndromes, such as Jakob-Creutzfeldt disease, autoimmune limbic encephalitis, autoimmune corticosteroid-responsive encephalopathy with thyroid autoimmunity, sepsis-associated encephalopathy, and acute disseminated encephalomyelitis, have imaging/EEG changes that are variable but which may include slowing and epileptiform activity. This overview highlighting EEG-imaging correlations may help the treating physician in the diagnosis, and hence the appropriate treatment, of patients with encephalopathy.