Objective differentiation of neonatal EEG background grades using detrended fluctuation analysis

• Main Authors: Vladimir eMatic, Joseph Perumpillichira Cherian, Ninah eKoolen, Amir Hossein Ansari, Gunnar eNaulaers, Paul eGovaert, Sabine eVan Huffel, Maarten eDe Vos, Sampsa eVanhatalo
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2015-04-01
• Series: Frontiers in Human Neuroscience
• Subjects: Asphyxia; detrended fluctuation analysis; multifractal; Brain monitoring; background EEG
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fnhum.2015.00189/full

A quantitative and objective assessment of background electroencephalograph (EEG) in sick neonates remains an everyday clinical challenge. We studied whether long range temporal correlations quantified by detrended fluctuation analysis (DFA) could be used in the neonatal EEG to distinguish different grades of abnormality in the background EEG activity.Long-term EEG records of 34 neonates were collected after perinatal asphyxia, and their background was scored in 1h epochs (8h in each neonate) as mild, moderate or severe. We applied DFA on 15 min long, non-overlapping EEG epochs (n=1088) filtered from 3-8Hz. Our formal feasibility study suggested that DFA exponent can be reliably assessed in only part of the EEG epochs, and in only relatively short time scales (10-60sec), while it becomes ambiguous if wider time scale are considered. This prompted further exploration whether paradigm used for quantifying multifractal DFA (MF-DFA) could be applied in a more efficient way, and whether metrics from MF-DFA paradigm could yield useful benchmark with existing clinical EEG gradings.Comparison of MF-DFA metrics showed a significant difference between three visually assessed background EEG grades. MF-DFA parameters were also significantly correlated to interburst intervals quantified with our previously developed automated detector. Finally, we piloted the intra-patient application of MF-DFA metrics and showed their evolution during patient recovery from asphyxia. Our exploratory study showed that neonatal EEG can be quantified using multifractal metrics, which might offer a suitable parameter to quantify the grade of EEG background, or to monitor changes in brain state that take place during long-term brain monitoring.