The cry as a vital sign: A smartphone based study protocol of neonatal cry acoustics in hypoxic ischemic encephalopathy

Background. Many Indian special newborn care units (SNCUs) cannot offer amplitude-integrated EEG (aEEG) or early MRI, so bedside judgement decides which newborns receive closer neurological attention. Earlier work found that asphyxiated newborns cry with a higher pitch and shorter phonation than healthy newborns, and a meta-analysis reported higher fundamental frequency, dysphonation and atypical melody in infants with neurological dysfunction, with wide differences between studies. Aim. To determine whether basic acoustic features of a smartphone-recorded pain cry (following a heel prick) can differentiate term newborns with HIE from control newborns. Also, to track changes in cry acoustics over the first 72 hours of life and evaluate their association with the clinical severity and short-term outcomes of encephalopathy. Design. A prospective, single centre diagnostic accuracy and cohort study in a tertiary SNCU. Three groups of term newborns are recorded: newborns with HIE, healthy comparators, and sick comparators who do not have HIE. Every newborn is recorded after the same stimulus, the first clinically indicated heel-prick. Newborns with HIE and sick comparators are recorded again at 24 hours, 72 hours and before discharge. A cry that is late or absent counts as a result and not as a missing value. Three clinicians blinded to group also classify the cries by listening, so the phone-based measures can be compared with the human ear. Analysis. The primary outcome is the area under the ROC curve of a logistic model with five pre-specified acoustic predictors. The target is 180 analyzable newborns (70 with HIE and 110 comparators). Reporting follows STARD and TRIPOD+AI. Relevance. In a South Asian trial, cooling did not reduce death or disability at 18 months and increased death alone. A cry tool in this setting is therefore proposed to help prioritize EEG, seizure surveillance, closer observation and referral. It is not proposed as a trigger for cooling. Keywords: neonatal encephalopathy; infant cry; acoustic analysis; smartphone; diagnostic accuracy; low-resource setting.