To develop and test the Neonatal Encephalopathy–Rating Scale (NE-RS), a new rating scale to grade the severity of neonatal encephalopathy (NE) within the first 6 hours after birth.

A 3-phase process was conducted: (1) design of a comprehensive scale that would be specific, sensitive, brief, and unsophisticated; (2) evaluation in a cohort of infants with neonatal encephalopathy and healthy controls; and (3) validation with brain magnetic resonance imaging findings and outcome at 2 years of age.

We evaluated the NE-RS in 54 infants with NE and 28 healthy infants. The NE-RS had excellent internal consistency (Cronbach alpha coefficient: 0.93 [95% CI 0.86-0.94]) and reliability (intraclass correlation coefficient in the NE cohort 0.996 [95% CI 0.993-0.998; P < .001]). Alertness, posture, motor response, and spontaneous activity were the top discriminators for degrees of NE. The cut-off value for mild vs moderate NE was 8 points (area under the curve [AUC] 0.99, 95% CI 0.85-1.00) and for moderate vs severe NE, 30 points (AUC 0.93, 95% CI 0.81-0.99). The NE-RS was significantly correlated with the magnetic resonance imaging score (Spearman Rho 0.77, P < .001) and discriminated infants who had an adverse outcome (AUC 0.91, 95% CI 0.83-0.99, sensitivity 0.82, specificity 0.81, positive predictive value 0.87, negative predictive value 0.74).

The NE-RS is reliable and performs well in reflecting the severity of NE within the first 6 hours after birth. This tool could be useful when assessing clinical criteria for therapeutic hypothermia in NE.