Quantitative analysis of maturational changes in EEG background activity in very preterm infants with a normal neurodevelopment at 1 year of age.

BACKGROUND The electroencephalographic (EEG) background pattern of preterm infants changes with postmenstrual age (PMA) from discontinuous activity to continuous activity. However, changes in discontinuity have been investigated by visual analysis only. AIM To investigate the maturational changes in EEG discontinuity in healthy preterm infants using an automated EEG detection algorithm. STUDY DESIGN Weekly 4h EEG recordings were performed in preterm infants with a gestational age (GA)<32weeks and normal neurological follow-up at 1year. The channel C3-C4 was analyzed using an algorithm which automatically detects periods of EEG inactivity (interburst intervals). The interburst-burst ratio (IBR, percentage of EEG inactivity during a moving time window of 600s) and mean length of the interburst intervals were calculated. Using the IBR, discontinuous background activity (periods with high IBR) and continuous background activity (periods with low IBR) were automatically detected and their mean length during each recording was calculated. Data were analyzed with regression and multivariate analysis. RESULTS 79 recordings were performed in 18 infants. All recordings showed a cyclical pattern in EEG discontinuity. With advancing PMA, IBR (R(2)=0.64; p<0.001), interburst interval length (R(2)=0.43; p<0.001) and length of discontinuous activity (R(2)=0.38; p<0.001) decreased, while continuous activity increased (R(2)=0.50; p<0.001). Multivariate analysis showed that all EEG discontinuity parameters were equally influenced by GA and postnatal age. CONCLUSION Analyzing EEG background activity in preterm infants is feasible with an automated algorithm and shows maturational changes of several EEG derived parameters. The cyclical pattern in IBR suggests brain organisation in preterm infant.

[1]  N. Bayley.  Manual for the Bayley Scales of Infant Development , 1969 .

[2]  José Ramón Castro Conde,et al.  Extrauterine life duration and ontogenic EEG parameters in preterm newborns with and without major ultrasound brain lesions , 2005, Clinical Neurophysiology.

[3]  C. Dreyfus-Brisac.  Ontogenesis of sleep in human prematures after 32 weeks of conceptional age. , 1970, Developmental psychobiology.

[4]  A. Okumura,et al.  Background electroencephalographic (EEG) activities of very preterm infants born at less than 27 weeks gestation: a study on the degree of continuity , 2001, Archives of disease in childhood. Fetal and neonatal edition.

[5]  T. Ogawa,et al.  Sequential changes in electroencephalogram continuity in very premature infants. , 1992, Electroencephalography and clinical neurophysiology.

[6]  Bichat-Claude Bernard,et al.  EEG patterns in 10 extreme premature neonates with normal neurological outcome: qualitative and quantitative data , 2003 .

[7]  B. van Sweden,et al.  Long-term EEG monitoring in the early premature: developmental and chronobiological aspects. , 1991, Electroencephalography and clinical neurophysiology.

[8]  M. Eiselt,et al.  Sleep State Organization in Premature Infants of Less Than 35 Weeks' Gestational Age , 1993, Pediatric Research.

[9]  Anthony G Marson,et al.  Spectral Analysis of Electroencephalography in Premature Newborn Infants: Normal Ranges , 2005, Pediatric Research.

[10]  P. Eken,et al.  The spectrum of leukomalacia using cranial ultrasound , 1992, Behavioural Brain Research.

[11]  Kimberlee Gauvreau,et al.  Electroencephalography in neonatal seizures: comparison of a reduced and a full 10/20 montage. , 2005, Pediatric neurology.

[12]  J. Volpe.  Neurology of the Newborn , 1959, Major problems in clinical pediatrics.

[13]  David Ley,et al.  Early amplitude‐integrated EEG correlates with cord TNF‐α and brain injury in very preterm infants , 2008, Acta paediatrica.

[14]  M. Scher,et al.  Cyclicity of Neonatal Sleep Behaviors at 25 to 30 Weeks' Postconceptional Age , 2005, Pediatric Research.

[15]  M. Gunning,et al.  Quantitative electroencephalographic patterns in normal preterm infants over the first week after birth. , 2006, Early human development.

[16]  G. Holmes,et al.  Prognostic value of background patterns in the neonatal EEG. , 1993, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[17]  E. Draper,et al.  Chronic lung disease of prematurity and intrauterine growth retardation: a population-based study. , 2003, Pediatrics.

[18]  F. Torres,et al.  The EEG of the early premature. , 1985, Electroencephalography and clinical neurophysiology.

[19]  G Cioni,et al.  Background EEG activity in preterm infants: correlation of outcome with selected maturational features. , 1994, Electroencephalography and clinical neurophysiology.

[20]  Floris Groenendaal,et al.  Sleep-Wake Cycling on Amplitude-Integrated Electroencephalography in Term Newborns With Hypoxic-Ischemic Encephalopathy , 2005, Pediatrics.

[21]  M. André,et al.  Normal EEG in very premature infants: reference criteria , 2000, Clinical Neurophysiology.

[22]  H. Monyer,et al.  Interburst interval measurements in the EEGs of premature infants with normal neurological outcome. , 1989, Electroencephalography and clinical neurophysiology.

[23]  R. Oozeer,et al.  Continuous 4-channel EEG monitoring: a guide to interpretation, with normal values, in preterm infants. , 1987, Neuropediatrics.

[24]  C T Lombroso,et al.  Neonatal Polygraphy in Full‐Term and Premature Infants: A Review of Normal and Abnormal Findings , 1985, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[25]  S. Bambang Oetomo,et al.  Analyzing EEG maturation in preterm infants : the value of a quantitative approach , 2008 .

[26]  G. Benda,et al.  Prolonged inactive phases during the discontinuous pattern of prematurity in the electroencephalogram of very-low-birthweight infants. , 1989, Electroencephalography and clinical neurophysiology.

[27]  Robert R. Clancy,et al.  Sensitivity of Amplitude-Integrated Electroencephalography for Neonatal Seizure Detection , 2007, Pediatrics.