BACKGROUND: The Neurologic and Adaptive Capacity Score (NACS) is a multi-item scale that was published in 1982 to measure the effects of intrapartum drugs on the neonate. Although this scoring system has been widely used in obstetric anesthesia research, studies confirming its reliability have not been published. The purpose of this study was to assess the reliability of the NACS. METHODS: Two teams of observers were trained to perform the NACS on healthy, term neonates born in the vertex presentation. Two examinations were performed on each neonate within the first 2.5 h of life. Simultaneous (or "split-half") reliability was assessed using the alpha coefficient. Test-retest reliability was assessed using the intraclass correlation coefficient. The test was considered to be reliable if a was greater than 0.7 and the intraclass correlation coefficient was greater than 0.6. RESULTS: Two hundred babies were studied. The a was 0.47 and the intraclass correlation coefficient was 0.38 (95% confidence interval, 0.24-0.52). CONCLUSIONS: The NACS had poor reliability both on simultaneous testing and in the test-retest situation when used to evaluate term, healthy neonates. The authors suggest that other measures need to be developed to evaluate the effect of intrapartum drug administration in the neonate. Health measurement scales should undergo rigorous assessment for reliability and validity before they are used in clinical practice or for research purposes.
BACKGROUND: The Neurologic and Adaptive Capacity Score (NACS) is a multi-item scale that was published in 1982 to measure the effects of intrapartum drugs on the neonate. Although this scoring system has been widely used in obstetric anesthesia research, studies confirming its reliability have not been published. The purpose of this study was to assess the reliability of the NACS. METHODS: Two teams of observers were trained to perform the NACS on healthy, term neonates born in the vertex presentation. Two examinations were performed on each neonate within the first 2.5 h of life. Simultaneous (or "split-half") reliability was assessed using the alpha coefficient. Test-retest reliability was assessed using the intraclass correlation coefficient. The test was considered to be reliable if a was greater than 0.7 and the intraclass correlation coefficient was greater than 0.6. RESULTS: Two hundred babies were studied. The a was 0.47 and the intraclass correlation coefficient was 0.38 (95% confidence interval, 0.24-0.52). CONCLUSIONS: The NACS had poor reliability both on simultaneous testing and in the test-retest situation when used to evaluate term, healthy neonates. The authors suggest that other measures need to be developed to evaluate the effect of intrapartum drug administration in the neonate. Health measurement scales should undergo rigorous assessment for reliability and validity before they are used in clinical practice or for research purposes.