Cerebral glucose metabolism and early EEG/aEEG in term newborn infants with hypoxic-ischemic encephalopathy

Abstract

The objective was to investigate how early electrocortical background pattern, as recorded with amplitude integrated EEG (aEEG), correlates with global and regional cerebral glucose metabolism (CMRgl) measured by positron emission tomography during the subacute phase after birth asphyxia. Nineteen term infants with hypoxic-ischemic encephalopathy were investigated. The aEEG background was evaluated at 0-6, 6-12, 12-24, 24-48, and 48-72 h postnatal age, and classified into four categories according to increasing degree of abnormality. The aEEG were also evaluated for sleep-wake cycling and epileptic seizure activity. CMRgl was measured by positron emission tomography with 2-(18F) fluoro-2-deoxy-d-glucose at a median (range) postnatal age 10 (4-24) d. Increasing degree of abnormality in aEEG correlated significantly with decreasing CMRgl: at 6-12 h (-0.593; 0.012) (r value; p value), 12-24 h (-0.669; 0.003), and 24-48 h (-0.569; 0.014) postnatal age. Presence of sleep-wake cycling at 0-6 h (0.697; 0.012), 6-12 h (0.668; 0.003), and 12-24 h (0.612; 0.009) of age correlated with increased CMRgl. Delayed seizure activity at 12-24 h correlated with decreased CMRgl (-0.661; 0.004). Infants with abnormal aEEG at 6-12 h had lower CMRgl in all regions of the brain compared with infants with normal aEEG. CMRgl of any specific region of the brain was not significantly more correlated to aEEG than CMRgl of other regions. Early electrocortical background patterns, early presence of sleep-wake cycling, and delayed seizure activity were highly correlated with global CMRgl measured during the subacute phase after asphyxia, but did not correlate with any specific pattern of regional uptake.