Reliability and validity of the Taiwanese version of the Neurological Disorders Depression Inventory for Epilepsy (Tw-NDDI-E)

Abstract

Introduction: Depression is the most commonly seen psychiatric co-morbidity of epilepsy. Depression in patients with epilepsy (PWE) is underrecognized. The Neurological Disorders Depression Inventory for Epilepsy (NDDI-E) is a useful tool to screen for major depressive episodes (MDEs) in PWE. This study validated the Taiwanese version of the NDDI-E using data from adult PWE in our hospital.

Method: PWE were recruited from the Taipei Veterans General Hospital from April 2017 to December 2019. The Chinese version of the NDDI-E for the Taiwanese population and the Beck Depression Inventory-II (BDI-II) were completed as part of the self-rated psychiatric assessments. The mood disorder module of the Mini International Neuropsychiatric Interview (MINI) was completed as part of the psychiatric assessment before the self-rated assessment. Internal consistency, external validation, and receiver operator characteristic (ROC) curve analysis were used to assess the utility of the Taiwanese version of the NDDI-E.

Results: We recruited 109 patients during the 33-month study period. The mean age was 33.1 ± 8.94 years old. The mean NDDI-E score was 12.32 ± 4.96. The mean BDI-II score was 13.26 ± 12.77. All NDDI-E items were significantly positively associated with the corrected overall NDDI-E score (Cronbach's alpha = 0.902, r = 0.825, p < 0.0001). The cut-off point for the NDDI-E determined with receiver operating characteristic (ROC) curve analysis is 15 (sensitivity = 85.0%, specificity = 87.64%).

Conclusion: The Chinese version of the NDDI-E adapted for the Taiwanese population is a reliable and valid self-reported questionnaire for detecting MDE in Taiwanese PWE.

Keywords: Depression; Epilepsy; NDDI-E; Taiwanese.