Cultural Adaption, Validation and Factor Analysis of the Persian Version of the Non-Nutritive Sucking Scoring System

Abstract

Background: Valid and reliable tools are required to measure non-nutritive sucking and oral feeding readiness of preterm infants. The aim of this study was to translate the Non-Nutritive Sucking scoring system (NNS) into Persian language and to evaluate its measurement properties.
 Methods: A cross-sectional study was conducted to translate and cross-culturally adapt the NNS to Persian language (P-NNS) following steps described in guidelines. Eighty-eight preterm infants participated in this study. Psychometric properties of floor/ceiling effects, internal consistency reliability, inter-rater reliability, Standard Error of Measurement (SEM), Smallest Detectable Change (SDC) and construct validity were tested. Factor analysis was performed to determine the P-NNS structure.
 Results: There were no floor or ceiling effects that indicate the content and responsiveness of P-NNS. Internal consistency was high (Cronbach’s α 0.905). Item–total correlations exceeded acceptable standard of 0.3 for the all the items (0.3–0.9). The inter-rater reliability was excellent (k=0.91, SE=0.04; p<0.001). SEM and SDC were 8.04 and 22.28, respectively. Construct validity was supported by a significant correlation between the P-NNS total score and the Persian version of the Early Feeding Skills (EFS) total score (r=0.94, p<0.001). Explanatory factor analysis revealed 2 components for p-NNS.
 Conclusion: The P-NNS was cross-culturally adapted to Persian and demonstrated to be a reliable and valid instrument to measure non-nutritive sucking and oral feeding readiness of preterm infants.