Electrogastrography-Derived Mean Power Ratio as an Exploratory Objective Measure of Feeding Intolerance in Preterm Infants

Feeding intolerance (FI) is common in preterm infants and disrupts enteral nutrition. Because clinical signs of FI are nonspecific, objective biomarkers are needed. In this exploratory study, we evaluated whether electrogastrography (EGG) can distinguish infants with FI from those with no FI (NFI) based on their gastric response to feeding. For each infant, the first available weekly EGG recording (postnatal week 1 or, if unavailable, week 2), comprising two consecutive feeding cycles, was analyzed. Each recording included pre-, during-, and post-feed segments. Power spectral density (PSD) was computed over 0.5-9 cycles per minute (cpm) to derive baseline mean PSD (mPSD) and PSD ratios (PSDR) for during/pre- and post/pre-feeding (PSDR_Dur/Pre, PSDR_Post/Pre). Mean power ratios (mPR) were calculated across bradygastria, normogastria, and tachygastria frequency bands. Group differences were assessed using bootstrap resampling. Eighty-four infants were analyzed (75 NFI, 9 FI). Baseline mPSD values were comparable between the two groups. FI infants demonstrated lower PSDR_Dur/Pre values in the bradygastria and tachygastria bands, whereas normogastria responses were similar. No differences were observed in PSDR_Post/Pre. EGG detected attenuated gastric activity specifically during feeding and not after feeding in infants with FI, supporting its potential as a non-invasive physiologic marker that warrants further validation.