Transcultural Adaptation and Validation of Kannada version of the National Institute of Health Stroke Scale (NIHSS)

BACKGROUND AND PURPOSE: The National Institute of Health Stroke Scale (NIHSS) is widely used in clinical practice to evaluate stroke-related neurological deficits. The aim of this study was to develop Kannada language version of the NIHSS (Ka-NIHSS) and determine its validity and reliability. MATERIALS AND METHODS: In the first phase of the study, Ka-NIHSS was adapted based on cultural and linguistic peculiarities. In the next phase, 51 acute stroke patients were prospectively enrolled in the study. The concurrent validity of the Ka-NIHSS was evaluated by comparison with the Glasgow Coma Scale (GCS) and the modified Rankin Scale (mRS). The predictive validity was assessed by comparison with Barthel Index (BI) score and mRS at a 90-day telephonic follow-up. The reliability was evaluated using the kappa statistics for inter-rater agreement between two independent raters and intra-class correlation coefficient (ICC) analysis. The inter-rater agreement of videotaped assessment of items 9 and 10 between four independent raters was evaluated using kappa statistics. RESULTS: Ka-NIHSS scores highly correlated with GCS (P = –0.74 P < 0.001) and mRS (P = 0.85, P < 0.001) at baseline. It moderately correlated with mRS (P = 0.67, P < 0.001) and BI (P = –0.64, P < 0.001) at 90 days follow up. Inter-rater reliability was high between the two examiners, with kappa values ranging from 0.66 to 0.95. The inter-rater agreements of the video assessment of items 9 and 10 for nine patients among four raters were 0.81 and 1 respectively. CONCLUSIONS: Ka-NIHSS is a valid and reliable tool for assessing neurological deficits in Kannada-speaking stroke patients.