Electroencephalography and clinical neurophysiology
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Electroencephalogr Clin Neurophysiol · Nov 1984
Monitoring of multimodality evoked potentials during open heart surgery under hypothermia.
Multimodality evoked responses (ERs) were monitored in 16 adults who had cardiac surgery under cardiopulmonary bypass and moderate hypothermia (19-25 degrees C). Cooling affected all sensory ERs by progressively increasing the latencies of the major components. The effect was more profound on the later than on the earlier ER components. ⋯ Brain-stem auditory evoked responses (BAERs) were consistently present at temperatures above 25 degrees C, wave V was recordable in majority between 20 and 25 degrees C. All sensory ERs disappeared with severe hypothermia (20 degrees C or less) except the components generated more peripherally such as N10 of the short latency SERs. We feel that BAERs and short latency SERs may serve as useful intraoperative monitors of brain function during hypothermia.
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Electroencephalogr Clin Neurophysiol · Apr 1984
Alumina cream-induced focal motor seizures in cats. V. Unilateral lesions of the brain-stem reticular formation.
The effect of unilateral mesencephalic (MRF) and pontine (PRF) lesions on EEG-EMG patterns of type B and C alumina cream induced focal motor seizures was studied on cats with chronically implanted electrode and cannula lesion systems. EEG patterns included number, amplitude and contralateral propagation of type B spikes and occurrence and duration of type C tonic-clonic discharges. ⋯ They also reduced amplitude of type B muscular jerks and blocked type C tonic contradversion with a significant decrease in EMG-MUA time locked to the onset of type B spikes and type C paroxysmal EEG discharges. (2) PRF lesions contralateral to the cortical epileptogenic focus produced an effect on muscular contractions of type B and C seizures similar to that produced by ipsilateral MRF lesions. PRF lesions, however, did not significantly change the EEG patterns of type B and C seizures. (3) Neither MRF lesions contralateral nor PRF lesions ipsilateral to the cortical epileptogenic focus produced significant changes on EEG and EMG patterns of types B and C epileptic seizures.
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Electroencephalogr Clin Neurophysiol · Dec 1983
Spinal and far-field components of human somatosensory evoked potentials to posterior tibial nerve stimulation analysed with oesophageal derivations and non-cephalic reference recording.
Somatosensory evoked potentials (SEPs) were elicited by stimulation of the right posterior tibial nerve at the ankle in 20 experiments on 18 normal adults. A non-cephalic reference on the left knee was used throughout (with triggering of averaging cycles from the ECG), except for recording the peripheral nerve potentials. The responses were recorded along the spine, from oesophageal probes and from the scalp. ⋯ The P31 reflects the initial volley in the medial lemniscus. The P40 at Cz represents the cortical response of the foot projection. Average central CVs were calculated and discussed.
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Electroencephalogr Clin Neurophysiol · Mar 1983
Middle-latency auditory evoked responses during open-heart surgery with hypothermia.
Middle-latency auditory evoked responses (MLRs) were recorded from infants and adults before and during open heart surgery. Hypothermia was induced through perfusion cooling by cardiopulmonary bypass. In infants deep hypothermia (to 15 degrees C nasopharyngeal temp.) was often followed by the induction of total circulatory arrest. ⋯ The MLRs proved to be resistant to muscle relaxation induced by pancuronium and to anesthesia induced and maintained in most cases by fentanyl. In most cases MLR peak latencies were progressively delayed as temperature decreased. Hypotension resulted in decreased MLR (Pa) amplitude.
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Electroencephalogr Clin Neurophysiol · Jan 1981
Case ReportsCoexistence of triphasic waves and alpha-coma pattern.
The coexistence of triphasic waves and alpha-coma pattern in an EEG was observed in a 67-year-old comatose man following cardiopulmonary arrest, while his brain stem functions were intact. Although they may be diagnostically and prognostically significant, these EEG findings can be hard to recognize. These two distinct EEG patterns do not seem to be mutually exclusive.