Italian validation of the Neck Dissection Impairment Index questionnaire

Objective: The Neck Dissection Impairment Index (NDII) questionnaire is a useful and validated Quality of Life (QoL) evaluation instrument in patients undergoing major head-neck surgery. Its English version has been used in several studies in the last years. The aim of this work is to validate the NDII in Italian for both patient assessment and future studies. Materials and methods: Cross-cultural adaptation of the NDII was performed using standard techniques. Items of the original NDII were translated into Italian by a professional translator and two bilingual investigators. A final consensus version was obtained and given to two professional translators to produce a literal translation into English. The two translators and an expert committee synthesised the results of the translations in an English back-translated version that was compared with the original to check that they had the same semantic value. Results: Finally, a total of 42 patients completed both copies of the translated questionnaires. Internal consistency proved to be excellent, with Cronbach's alpha = 0.95. Conclusions: The NDII was successfully translated into Italian and its use was easy for patients. The translation of the NDII can represent a useful tool for individual patient assessment and future research.