Fz theta/alpha bursts: a transient EEG pattern in healthy newborns.

We named transient activity recorded from midline frontal area 'Fz theta/alpha bursts' and investigated their characteristics and clinical significance. Polygraphic examinations were carried out on a total of 155 infants from 35 to 46 weeks of postconceptional age. Fz theta/alpha bursts were recorded in 40 (36%) of 111 infants without neurological problems. Especially these bursts were found in 33 (55%) of 60 infants at 38-42 weeks of postconceptional age. They occurred in pre-term as well as in full-term newborns. Three hundred and sixty-two Fz theta/alpha bursts were recorded from 40 infants without neurological problems. Ninety-one percent of them were found in quiet sleep, and others in indeterminate sleep. None of them were recorded in active sleep. Fz theta/alpha bursts did not occur synchronously with frontal or temporal sharp transients. The incidence of Fz theta/alpha bursts in infants with abnormal neurological signs was lower than in control infants (4/44 vs. 37/73; P less than 0.01). The bursts were not detected in EEGs with moderately or more severely depressed background. One hundred and thirty-five infants were followed up for more than 12 months. Fz theta/alpha bursts were recorded in 38 (35%) of 109 infants with normal outcome, and in only 1 (4%) of 26 infants with abnormal outcome. Our results indicated that Fz theta/alpha bursts were of normal EEG components without pathological significance.