Assessment of Prolonged Pain in Infants With Excessive Crying: the Role of Thermal Imaging

The EDIN is a validated behavioral scale for the heteroassessment of pain in newborns and infants up to 9 months of age. The EDIN scale includes 5 assessment criteria: facial expression, movements, sleep, interactive behavior, and comfort. Each item is scored on a 3-point scale based on symptom intensity; a score of 5 or higher indicates probable pain, and analgesia is recommended. It is easy to use, quick to administer (about 3 minutes), reliable (0.69), has good internal validity (0.92), and has the advantage of assessing prolonged pain.

Cortisol is a steroid hormone involved in the stress response. Capillary cortisol levels have been studied in newborns as a biomarker of chronic stress and are associated with chronic pain in adults.

Capillary hair sampling is a noninvasive and rapid method; the samples are easy to store and remain stable over time. Protocols have been validated for the collection and analysis of capillary cortisol levels in preterm infants using hair samples weighing less than 2.5 mg.

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Full-body and facial thermographic images will be divided into regions of interest based on their vascular distribution. Asymmetries in body and facial temperatures will be systematically assessed. The child will be filmed in the supine position and then in the prone position, lying on their back, for 2 minutes on each side. Measurements will be taken using an OPTRIS 450 PI thermal camera. The images will then be analyzed by a specialized engineer who is blinded to the assignment group.

Skin temperature regulation is central to the body's thermoregulation and is symmetrical and instantaneous under normal physiological conditions. Asymmetrical qualitative and quantitative changes in temperature indicate a metabolic, hemodynamic, or neurological alteration in thermoregulation in the affected region.

Each infant's general movements will be filmed and recorded according to the protocol described by Einspieler and his team. The infant will be filmed in the supine position, wearing only a diaper or onesie, for 2 to 5 minutes of active wakefulness (without crying, interaction, a pacifier, or hiccups). This is currently the best clinically available method for assessing the neurological status of infants under 6 months of age. The assessment will be conducted by two independent observers, trained in the analysis of gross motor movements and blinded to the assignment group (GM Trust Basic and Advanced), who will assign a GMOS-R score.

The Bayley-4 scales allow for the qualitative and quantitative analysis of motor development (fine and gross motor skills). The scale will be administered by the experimenter but scored by an external observer trained in administering the Bayley and blinded to the assignment group.