Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society
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J Clin Neurophysiol · Feb 2012
Test-retest reliability of contact heat-evoked potentials from cervical dermatomes.
The purpose of this study was to investigate the test-retest reliability of contact heat-evoked potentials (CHEPs) in neurologically healthy subjects from cervical dermatomes (C4-C8). Seventeen individuals underwent test-retest examination of cervical CHEPs. Peak latencies and peak-to-peak amplitude of N2-P2 and ratings of perceived intensity were analyzed using test-retest reliability statistics (intraclass correlation coefficients [ICCs] and Bland-Altman confidence parameters). ⋯ Superior peak-to-peak amplitude test-retest reliability was found for CHEPs. In conclusion, the test-retest reliability of dSSEP and CHEP parameters supports the fact that these outcomes can be used to objectively track changes in spinal conduction in the dorsal column and spinothalamic tract, respectively. The reliable acquisition of CHEPs may depend on the intensity of the sensation reported by the subject for a given area of skin stimulated.
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J Clin Neurophysiol · Dec 2011
ReviewNeurophysiologic intraoperative monitoring of the glossopharyngeal and vagus nerves.
Neurophysiologic intraoperative monitoring (NIOM) of the glossopharyngeal and vagus nerves (CN IX and X) is often used during surgeries involving the lower brain stem. Although both of these nerves contain sensory, autonomic, and motor fibers, it is the motor fibers that are most amenable to NIOM. CN IX supplies the stylopharyngeus muscle, and CN X supplies striated muscles in the soft palate, pharynx, and larynx. ⋯ Various surface and needle electrodes can be used to monitor these muscle groups. When CN IX is monitored, CN X should also be monitored, as it is often needed to differentiate when CN IX is selectively activated. Data are accumulating noting the use of monitoring these CN in tumor surgeries involving the lower brain stem.
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The aim was to determine the electroencephalographic (or electroencephalogram [EEG]) findings predictive of functional outcome in a subset of patients with acute subdural hematoma (SDH) with epileptiform activity on their EEG. Twenty-four patients who underwent evacuation for acute or acute-on-chronic SDH and with epileptiform activity on EEG were identified retrospectively. Their EEGs were reviewed and the findings categorized along with clinical information, the preoperative computed tomography (CT) scan, and functional outcome. ⋯ The EEG findings in this group of patients were complex. Epileptiform discharges were common, and specific types were associated with midline shift on neuroimaging and poor functional outcome at hospital discharge. Improvement in follow-up EEG examinations over time was predictive of good long-term functional outcome.
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J Clin Neurophysiol · Oct 2011
Time-frequency analysis of somatosensory evoked potentials for intraoperative spinal cord monitoring.
To evaluate the potential use of time-frequency analysis and its reliability in intraoperative somatosensory evoked potential (SEP) monitoring. ⋯ The SEP peak component was found stable and reliable during the different stages of surgery. For clinical application purpose, time-frequency analysis was suggested to be an additional monitoring method besides the conventional amplitude/latency measurement since it provided a more reproducible and prompt response to the potential injury in intraoperative SEP monitoring.
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J Clin Neurophysiol · Oct 2011
Application of electrophysiologic techniques in poor outcome prediction among patients with severe focal and diffuse ischemic brain injury.
To explore various electrophysiologic examinations as predictors for poor outcome in patients with severe ischemic brain injury, by comparing the prognostic ability of EEG, short-latency somatosensory evoked potentials (SLSEP), and brain stem auditory evoked potentials (BAEP). ⋯ The predictive power of electrophysiologic examinations is different according to the etiology of ischemic brain injury. Short-latency somatosensory evoked potentials (N20) can be considered the most powerful method to predict poor outcome in anoxic-ischemic encephalopathy. Combination of EEG (unfavorable EEG patterns) and SLSEP (N20)/BAEP (wave V) is best suited in massive hemispheric infarction to predict poor outcome.