Predictive value of the NIHSS for ADL outcome after ischemic hemispheric stroke: does timing of early assessment matter?

Background and purpose: Early prediction of future functional abilities is important for stroke management. The objective of the present study was to investigate the predictive value of the 13-item National Institutes of Health Stroke Scale (NIHSS), measured within 72 h after stroke, for the outcome in terms of activities of daily living (ADL) 6 months post stroke. The second aim was to examine if the timing of NIHSS assessment during the first days post stroke affects the accuracy of predicting ADL outcome 6 months post stroke. Methods: Baseline characteristics including neurological deficits were measured in 188 stroke patients, using the 13-item NIHSS, within 72 h and at 5 and 9 days after a first-ever ischemic hemispheric stroke. Outcome in terms of ADL dependency was measured with the Barthel Index (BI) at 6 months post stroke. The area under the curve (AUC) from the receiver operating characteristic (ROC) was used to determine the discriminative properties of the NIHSS at days 2, 5 and 9 for outcome of the BI. In addition, at optimal cut-off odds ratio (OR), sensitivity, specificity, positive (PPV) and negative predicted values (NPV) for the different moments of NIHSS assessment post stroke were calculated. Results: One hundred and fifty-nine of the 188 patients were assessed at a mean of 2.2 (1.3), 5.4 (1.4) and 9.0 (1.8) days after stroke. Significant Spearman rank correlation coefficients were found between BI at 6 months and NIHSS scores on days 2 (r