Objective: To evaluate an electroencephalography (EEG)-based index, the Cerebral Health Index in babies (CHI/b), for identification of neonates with high Sarnat scores and abnormal EEG as markers of hypoxic ischemic encephalopathy (HIE) after perinatal asphyxia.Study Design: This is a retrospective study using 30 min of EEG data collected from 20 term neonates with HIE and 20 neurologically normal neonates. The HIE diagnosis was made on clinical grounds based on history and examination findings. The maximum-modified clinical Sarnat score was used to grade HIE severity within 72 h of life. All neonates underwent 2-channel bedside EEG monitoring. A trained electroencephalographer blinded to clinical data visually classified each EEG as normal, mild or severely abnormal. The CHI/b was trained using data from Channel 1 and tested on Channel 2. Result:The CHI/b distinguished among HIE and controls (P<0.02) and among the three visually interpreted EEG categories (P<0.0002). It showed a sensitivity of 82.4% and specificity of 100% in detecting high grades of neonatal encephalopathy (Sarnat 2 and 3), with an area under the receiver operator characteristic (ROC) curve of 0.912. CHI/b also identified differences between normal vs mildly abnormal (P<0.005), mild vs severely abnormal (P<0.01) and normal vs severe (P<0.002) EEG groups. An ROC curve analysis showed that the optimal ability of CHI/b to discriminate poor outcome was 89.7% (sensitivity: 87.5%; specificity: 82.4%). Conclusion:The CHI/b identified neonates with high Sarnat scores and abnormal EEG. These results support its potential as an objective indicator of neurological injury in infants with HIE.

To test the reliability of amplitude-integrated electroencephalogram (aEEG) in cerebral hypoxic ischemia (HI), 12 neonatal piglets subjected to different levels of HI are divided into three groups based on the histological outcomes obtained 4 days after experiment. Results show that concomitant with the increased severity of brain injury, the upper and lower margins of aEEG decrease significantly (p < 0.05) during early recovery period after HI (about 2 hours post-resuscitation). We conclude that aEEG method reliably reflects hypoxic-ischemic cerebral injury and constitutes a valuable monitoring tool in neonatal intensive care unit (NICU).

Background Cardiac arrest (CA) can lead to significant neurological damage following resuscitation. A real-time tool for monitoring of neurological status in CA survivors is likely to have a significant impact on post-CPR therapy. To avoid typical subjective prediction of outcome, we have developed a quantitative EEG-based Cerebral Health Index (CHI), a multiparametric algorithm combining several separate spectral, temporal and probabilistic features. CHI is a measure of outcome that evaluates and scores the EEG post-resuscitation from CA. In the present study, we compared CHI to a species-specific behavioral outcome scoring measure, the Neurological Deficit Scores (NDS). Previously calibrated and tested, NDS includes multiple generalized neural, motor, sensory and behavioral subscores. We demonstrated the utility of CHI as a measure of monitoring neurological status as given by NDS. Methods CHI is an empirically trained algorithm that allows for parameter weighting to uniquely characterize the recovering EEG. We investigated the utility of CHI by comparing 72-h CHI values to 72-h of an asphyxial CA rodent model. Sixteen rats underwent a baseline EEG recording followed by 7- or 9-min asphyxia and anesthesia washout which led to CA. The NDS was scored at 72 hr after CA with concurrent 30-min EEG recording. The rats were divided into two groups: 8 rats with known NDS outcomes were used for training the CHI algorithm and 8 rats were used for testing the algorithm in a single blinded fashion. CHI values of the testing group were then compared to their corresponding NDS outcomes via Receiver Operator Characteristic (ROC) curve calculation. Results Physiological measures and arrest times were comparable in both poor and good outcome animals. On a scale basis of 0–80, average CHI values were 70 (±3.8) and 51 (±4.4) for the good and bad outcome animals, respectively. This translated to respective t-test p-values of p≤0.05. ROC analyses on testing cohorts at 72 hr showed an average area under the curve of 0.9. Conclusion CHI is a multi-feature index for accurately describing neurological status after CA in rats. CHI can potentially be used to supplement the traditional neurological exam to make EEG characterization a routine part of post-CA assessments.

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