Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2
Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2
9Activation ProceduresTHORU YAMADA and ELIZABETH MENGActivation procedures include various sensor}'' and pharmacological stimulations to alter the phy Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2ysiological state. They are usually aimed at eliciting or enhancing abnormal activity, especially epileptiform activity. The most commonly used sensory stimulation is photic stimulation. Others include tactile or electrical stimuli for somatosensory stimulation and music or sounds for auditory stimu Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2lation. Pharmacological activation includes pentylenetetrazol to induce a seizure or benzodiazepine to attenuate one. The most routine activation procEbook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2
edures in any EEG laboratory are hyperventilation (HV), photic stimulation (PS), and sleep.NORMAL HYPERVENTILATION RESPONSEThis procedure consists of 9Activation ProceduresTHORU YAMADA and ELIZABETH MENGActivation procedures include various sensor}'' and pharmacological stimulations to alter the phy Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2ed by asking the child to blow on a pinwheel. A characteristic IIV response consists of bilaterally diffuse and synchronous slow-wave bursts, initially with theta frequency and then progressing to delta frequency. This is called “HV buildup” (Figs. 9-1A and B and 9-2A and B). rhe amplitude may reach Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2 as high as 500 pV. Theta-delta buildup by IIV is usually anterior dominant in adolescents or adults but may be posterior dominant in children. TheseEbook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2
occur in a serial semirhythmic fashion with fluctuating amplitude (Video 9-1). The effect is most prominent in children between the ages 8 and 12 year9Activation ProceduresTHORU YAMADA and ELIZABETH MENGActivation procedures include various sensor}'' and pharmacological stimulations to alter the phy Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2may be less than 10%.' HV effects, however, vary considerably from one individual to another. Physiologically, HV reduces the carbon dioxide concentration (PCO2), which causes vasoconstriction and reduction of cerebral blood flow. The reduction of PCO2 (hypocapnia) is likely the major factor in prod Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2ucing HV buildup. HV buildup is enhanced by a blood sugar level below 80 mg/100 mL.-’ Therefore, HV buildup may be more prominent when the patient isEbook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2
hungry or his/her last meal was some time ago. In subjects who show- a low--voltage and poorly defined alpha rhythm, IIV may bring out a better define9Activation ProceduresTHORU YAMADA and ELIZABETH MENGActivation procedures include various sensor}'' and pharmacological stimulations to alter the phy Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 2-year-old boy. Note the increase of posterior delta waves (posterior slow waves of youth) and semirhythmic 3- to 4-Hz generalized delta-theta bursts during hyperventilation (B).'■ Xc>- si'^.^V-VF^V#-r*T.•.**♦••>* Ebook Practical guide for clinical neurophysiologic testing EEG (2/E): Part 29Activation ProceduresTHORU YAMADA and ELIZABETH MENGActivation procedures include various sensor}'' and pharmacological stimulations to alter the phyGọi ngay
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