lặp đi lặp lại và đánh giá cao tổ chức mô hình có thể bị nhầm lẫn với một xả của petit mal hoặc mal tiểu loại biến thể. Bất thường này là gần như liên tục, và trong nhiều trường hợp, nó cho thấy rõ ràng trong thức như trong các bản ghi đang ngủ. | 16 SEVERE ENCEPHALOPATHIC EPILEPSY IN INFANTS INFANTILE SPASMS WEST SYNDROME 253 Fp1-A1 Fp2-A2 C3-A1 C4-A2 O1-A1 O2-A2 T5-A1 T6-A2 Fp1-C3 Fp2-C4 C3-O1 C4-O2 C3-T3 C4-T4 T3-Fp1 T4-Fp2 FIGURE 16-3 Hypsarrhythmia. Digital recording from a 6-month-old male. repetitive and highly organized pattern that could be confused with a discharge of the petit mal or petit mal variant type. The abnormality is almost continuous and in most cases it shows as clearly in the waking as in the sleeping record. This prototypic pattern is usually seen in the early stages of the disorder and most often in younger infants younger than 1 year of age . The pattern has been reported in 7 to 75 of patients with infantile spasms 10 12 37-41 . In addition variations or modifications of this pattern may be seen in many patients. In 1984 we identified five variations of the originally described pattern after reviewing the 24-hour EEG-video monitoring studies in 67 infants with infantile spasms 29 . These variations include hypsarrhythmia with a consistent focus of abnormal discharge hypsarrhyth-mia with increased interhemispheric synchronization hypsarrhythmia comprising primarily high-voltage slow-wave activity with very little spike or sharp wave activity asymmetrical or unilateral hypsarrhythmia and hypsarrhythmia with episodes of generalized regional or localized voltage attenuation which in its maximal expression is referred to as the suppression-burst variant. These variations were subsequently confirmed by Alva-Moncayo et al 37 in 100 cases. In addition to demonstrating these basic variations 24-hour EEG-video monitoring studies have shown that hypsarrhythmia is a highly dynamic pattern with transient alterations in the pattern occurring throughout the day. The hypsarrhythmic activity tends to be most pronounced and to persist to the latest age in slow-wave non-rapid-eye movement NREM sleep. During NREM sleep there is a tendency for grouping of the multifocal spike and sharp wave discharges
