Chronologic changes in neonatal EEG findings in periventricular leukomalacia.

Objective: This study sought to clarify chronologic changes in neonatal electroencephalographic (EEG) findings in periventricular leukomalacia (PVL).
Methods: We obtained serial EEG findings for all premature infants who were admitted to our hospital at gestational age of < or =33 weeks between 1997 and 2006. EEG recordings were obtained on days 1 to 4, 5 to 14, 15 to 28, 29 to 56, and 57 to 84. Abnormal EEG findings were classified as acute-stage abnormalities (ASAs) or chronic-stage abnormalities (CSAs) and were subclassified as mild, moderate, or severe. PVL was classified as noncystic, localized cystic, or extensive cystic. The final diagnosis of PVL was made through neurologic assessment and MRI findings at 24 months.
Results: Fifty-five infants were diagnosed as having PVL, including 23 with noncystic PVL, 9 with localized cystic PVL, and 23 with extensive cystic PVL. ASAs were observed most frequently on days 1 to 4 and were observed rarely thereafter in all groups. CSAs were observed most frequently on days 5 to 14, were most severe on days 5 to 14, and then resolved within 1 to 2 months in all groups. CSAs in patients with extensive cystic PVL were more severe and persisted longer, compared with other groups. ASA and CSA severity was correlated with PVL severity.
Conclusions: EEG findings in PVL differed according to the severity of PVL and the time of recording. To detect PVL, > or =2 EEG recordings are recommended, 1 within 48 hours after birth, to detect ASAs, and 1 in the second week of life, to detect CSAs.