RT Book, Section A1 Laoprasert, Pramote SR Print(0) ID 1101636039 T1 Generalized Nonepileptiform Activity T2 Atlas of Pediatric EEG YR 2011 FD 2011 PB McGraw-Hill Education PP New York, NY SN 9780071623346 LK neurology.mhmedical.com/content.aspx?aid=1101636039 RD 2024/03/29 AB ▪ The EEG is unable to distinguish between different etiologies. The major usage of the EEG is to determine the severity of encephalopathy, prognosis, and response of treatment.▪ Common etiology:▸ Metabolic, toxic, inflammation, anoxic, and degenerative diseases▪ Few EEG patterns associated with more specific etiologies for the encephalopathy:▸ Periodic pattern:Anoxic encephalopathyCertain encephalitis▸ Triphasic waves (TWs) or 14- and 6-Hz positive spike bursts:Metabolic encephalopathy Lithium and ifosphamide toxicity▸ High-voltage beta activity:Benzodiazepine or barbiturate intoxication▸ Low-voltage fast patterns:Alcohol withdrawal▸ Bursts of high-voltage delta activity interspersed with mixed frequencies:PCP (angel dust) intoxication▪ Prognosis in most EEG patterns is usually correlated with underlying diseases and reactivity of EEG to external stimuli.▸ Ischemic strokes and anoxic ischemia after cardiorespiratory arrest are almost completely irreversible.▸ Brain injury produced by head trauma, subdural hemorrhages, and some intracranial hemorrhages, in the absence of raised intracranial pressure, may be partially, moderately, or occasionally wholly reversible.▸ Electrical disturbances with seizures and status epilepticus (SE), metabolic, and some toxic encephalopathies may be completely reversible.▪ Some particular patterns have been identified that may have some prognostic significance:▸ Poor prognosisTriphasic waves (TWs).Alpha coma (AC) patterns in patients with anoxic encephalopathy nonreactive to noxious stimuli.Continuously diffuse polymorphic delta activity (unless due to a toxic/metabolic disturbance) typically bodes poorly for the patient, when these patterns are low voltage.Marked bilateral suppression coma.Burst-suppression (B-S) patterns.▸ Better prognosis:Spindle coma (SC) patternsBeta coma▪ Severity:▸ Milder encephalopathy:Spontaneous variabilityEvidence of EEG reactivity to painful stimulation◊ Reduction of amplitude, increase in frequency, and reduction in the slow activity◊ Paradoxical activation, which is a period of more severe delta slowing following painful stimuli▸ Severe encephalopathy:Invariant EEG—no spontaneous variability or reactivity to external stimuli▪ Combination of diffuse and focal EEG abnormalities:▸ Associated focal process such as old infarction or tumor▸ Nonketotic hyperosmolar coma▸ Focal seizure▸ Herpes simplex encephalitis and Creutzfeldt-Jakob disease (CJD)