Quantification electroencephalography response to procedural pain during heel puncture in preterm infants

<i>Objective</i>. Pain assessment in preterm infants is often based on subjective observations, which may lack objectivity and are labor-intensive. Non-invasive EEG can serve as an objective assessment tool. However, no specific EEG feature within a particular frequency band and brain region has been reported for pain detection in the objective pain assessment of preterm infants. This study quantified electroencephalography (EEG) responses to procedural pain during a puncture in preterm infants, specifically analyzing three EEG parameters.<i>Approach</i>. Fifty-seven EEG datasets from forty-two preterm infants were analyzed across eight EEG channels. The differences between the upper and lower margins (UM-LM) of amplitude-integrated EEG (aEEG), as well as the five frequency bands (low delta, high delta, theta, alpha, and beta) of frequency power and time-frequency power, were used to characterize the response of the brain to pain during specific periods: before, during, and after the puncture.<i>Main results</i>. The Fp1 and Fp2 exhibited the most significant differences in the UM-LM aEEG differences between before vs during (Fp1:<i>p</i>= 0.0060, Fp2:<i>p</i>= 0.0031), before vs after (<i>p</i>< 0.0001), and during vs after (Fp1:<i>p</i>= 0.0427, Fp2:<i>p</i>= 0.025) the puncture. The C3 and C4 responded significantly to pain during the puncture in the frequency and time-frequency power, notably the time-frequency power in the low delta, which showed the most significant differences between the periods before vs during (<i>p</i>< 0.0001), before vs after (<i>p</i>< 0.0001), and during vs after (<i>p</i>= 0.0002) the puncture.<i>Significance</i>. The central brain region responds significantly to procedural pain in preterm infants, which is prominently detected in the low delta of time-frequency power. These findings support the use of EEG application as an objective and non-invasive method to identify and detect pain in nonverbal populations, focusing on specific critical channels and frequency bands.