Normal Pattern of the Cerebral Function Monitor Trace in Term and Preterm Neonates

Abstract

Cerebral Function Monitor (CFM) recordings were performed on 10 term and 19 preterm healthy infants. Term infants were monitored once, while preterm infants were followed serially. Forty-six recordings were made on 7, 14, 16 and 9 occasions in the age groups 30-31, 32-33, 34-35 and 36-37 weeks. All infants were examined clinically at 18 months of age and found healthy. By drawing weighted lines derived from the lower and upper limits of the CFM traces, mean values of minimum and maximum cerebral activity were calculated for the different age groups. In the term infants different CFM traces were identified corresponding to quiet sleep and active sleep. In the preterm infants a similar cyclic variability of the CFM trace was noted. A gradual increase in the minimum cerebral activity was found with increasing gestational age, resulting in a gradual narrowing of the trace.

Neurological maturation of late preterm infants at 34 wk assessed by amplitude integrated electroencephalogram

“…This limits gestational age related changes in aEEG (12)(13)(14) and focuses on the lower gestational age of late preterm infants who are known to have a higher frequency of morbidities which may require intensive care compared with infants at Articles Sommers et al 35-36 wk (9,15-17). Thus, accurate gestational age was critical and infants were enrolled only if a first trimester sonogram was available (18).…”

“…Cycles represent the repetitive changes between continuous and discontinuous EEG activity as described by Kidokoro et al (19). Cycle type was prospectively defined based on published criteria (12)(13)(14) and are described below (Figure 4). Cycles were visually identified and Analyze was used in cases of uncertainty to establish cycle criteria.…”

Using amplitude-integrated EEG in neonatal intensive care

“…Typically, a narrow bandwidth characterizes wakefulness and active sleep, whereas a wider bandwidth denotes quiet sleep. 22 In addition to normal and abnormal sleep-wake cycles, Hellström-Westas et al 13 suggest that an intermediate category of imminent/immature SWC be added to the presence or absence of cycling. 13 Infants with HIE have noticeable differences in SWC with regard to severity of encephalopathy.…”

“…Several key studies characterized cerebral function for infants >30 weeks. 22,39 Compared with term infants, the background pattern of less mature infants is more discontinuous. There are more frequent 'bursts', and the raw tracing of the EEG signal may show periods of relatively low voltage with sudden but infrequent bursts of high activity.…”

Calculation of compact amplitude-integrated EEG tracing and upper and lower margins using raw EEG data

“…Unfortunately, the amplitude of the aEEG margins, which serves as an important discriminating index, usually is measured semisubjectively with the naked eye from the voltage scale on printed paper [6,7]. In most cases, a line is drawn manually through the upper and lower margins of the aEEG tracing, with half of the voltage peaks (for the upper margin) or troughs (for the lower margin) below the line and half above [3,[8][9][10][11][12][13]. Therefore, potential bias may be introduced in the assessed amplitudes.…”