Objective: To study the characteristics of amplitude integrated electroencephalography (aEEG) in preterm infants and changes of maturation with gestational age.
Methods: aEEG monitoring was done within 3 days of age with domestically produced digital aEEG set (CFM3000). Duration of each recording was at least 4 hours. The continuity, sleep-wake cycle, voltage and bandwidth of all aEEG tracing were analyzed.
Results: The percent of continuity background increased from 30% of 28 weeks to 85.7% of 36 weeks (χ(2) = 28.2, P = 0.026); the percent of mature sleep-wake cycle increased from 10% of 28 weeks to 100% of 36 weeks (χ(2) = 192.4, P < 0.01). Low bound voltage increased with gestational age, from (6.8 ± 1.7) µV (28 w) to 9.7 - 10.1 µV (35 - 36 w) (F = 11.4, P < 0.01). Bandwidth of the narrow band decreases gradually with gestational age, from 1.45 cm (28 w) to (0.86 ± 0.24) cm (36 w) (F = 8.731, P < 0.01). The correlation coefficient for continuity, sleep-wake cycle, low bound voltage and bandwidth of narrow band, and total scores were 0.32, 0.81, 0.38, 0.55 and 0.78 respectively (P < 0.05).
Conclusion: The older the gestational age of infants at birth, the more mature the aEEG pattern, manifested as increased continuity and sleep-wake cycle, the higher low bound voltage and more narrowed bandwidth with increased gestational age.