Reliability and validity of a Japanese version of Neonatal Infant Pain Scale

Abstract

Aim

This study aimed to develop a Japanese version of the Neonatal Infant Pain Scale (NIPS) and evaluate its reliability and validity.

Methods

After the Japanese version of NIPS was created through translation and back-translation, the researchers assessed neonates' behavior during adhesive removal. Additionally, two observers watched a video from before to after the adhesive removal and evaluated the neonates' behavior at three-time points, such as “before,” “during,” and “after” adhesive removal. For construct validity assessment, total NIPS scores at the three time points were compared using the Friedman test. Internal reliability was confirmed by calculating Cronbach's alpha and item-to-item correlations and adjusted item-total correlations for the NIPS at the three time points.

Results

The total NIPS scores at three-time points (χ²=48.04, df=2, p<.001) had a significant difference, and total scores were high when pain procedures were implemented, confirming construct validity. Intraclass correlation coefficients of the total NIPS scores between researchers and observers were r=0.72 (p<.001), which confirmed inter-rater reliability. Cronbach's alphas for the NIPS “before,” “during,” and “after” adhesive removal were 0.95, 0.86, and 0.94, respectively. Correlation coefficients for the inter-item correlations ranged from 0.60–1.00 for “before,” 0.39–0.79 for “during,” and 0.65–0.94 for “after.” Adjusted item-total correlations ranged from 0.71–0.92 “before,” 0.61–0.80 for “during,” and 0.72–0.88 for “after.” These results confirm the internal reliability of NIPS.

Conclusion

The reliability and validity of the Japanese version of NIPS were confirmed. Japanese medical staff may assess a neonate's pain during medical procedures using the NIPS. Future use of NIPS will be widely expected in many situations with neonates, including in the neonatal unit of the obstetrics department beyond use in the NICU.