National Institutes of Health Stroke Scale (NIHSS) as An Early Predictor of Poststroke Dysphagia

Background: Despite the availability of multiple comprehensive screening methods to detect dysphagia during acute stroke care, consensus is lacking as to the best practice. Our previous study demonstrated favorable sensitivity of the Functional Independence Measure (FIM) compared with a bedside 3-sip test. However, the FIM is challenging to administer during acute stroke care. The National Institutes of Health Stroke Scale (NIHSS) is administered routinely in the emergency department. Objective: To evaluate the utility of the NIHSS as a predictor of clinically relevant poststroke dysphagia compared with FIM data in the same cohort. Design: Retrospective analysis. Setting: Academic medical center. Patients: Individuals with acute stroke who were admitted for acute care and later transferred to acute rehabilitation within the same institution. Methods: Clinically relevant dysphagia was defined as aspiration on modified barium swallow or laryngeal penetration on modified barium swallow requiring diet change, or aspiration pneumonia. NIHSS and FIM scores were compiled for all patients. Main Outcome Measurements: Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for NIHSS and FIM. Sensitivity and specificity of different values of NIHSS and FIM were analyzed via receiver operator characteristic curves. Results: Of 290 patients admitted to acute stroke rehabilitation, 88 (30%) manifested clinically relevant dysphagia during their rehabilitation stay. Sensitivity analyses suggested cut-off values for the NIHSS and the FIM of >9 and <55, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value for the NIHSS were 75%, 62%, 46%, and 85%, respectively. For the FIM, these parameters were 80%, 72%, 55%, and 92%, respectively. Conclusions: The NIHSS >9 and FIM <55 are moderately predictive of clinically relevant dysphagia. Although the NIHSS clinical test characteristics are not as favorable as the FIM, NIHSS appears to be more sensitive than some other reported methods such as a 3-sip water test. Further study into development of paradigms that incorporate NIHSS into initial assessment of dysphagia risk may be appropriate.