Assessment of aspiration risk in stroke patients with quantification of voluntary cough

Background: Dysphagia and subsequent aspiration are serious complications o f acute stroke that may be related to an impaired cough reflex. It was hypo thesized that aspirating stroke patients would have impaired objective meas ures of voluntary cough as compared with both nonstroke control subjects an d nonaspirating stroke patients. Methods: Swallowing was evaluated by stand ard radiologic or endoscopic methods, and stroke patients were grouped by a spiration severity (severe, n = 11; mild, n = 17; no aspiration, n = 15). A irflow patterns and sound pressure level (SPL) of voluntary cough were meas ured in stroke patients and in a group of normal control subjects (n 18). I nitial stroke severity was determined retrospectively with the Canadian Neu rological Scale. Results: All cough measures were altered in stroke patient s as a group relative to nonstroke control subjects. Univariate analysis sh owed that peak flow of the inspiration phase (770.6 +/- 80.6 versus 1,120.1 +/- 148.4 mL/s), SPL (90.0 +/- 3.1 versus 100.2 +/- 1.6 dB), peak flow of the expulsive phase (875.1 +/- 122.7 versus 1,884.1 +/- 221.6 mL/s), expuls ive phase rise time (0.34 +/- 0.1 versus 0.09 +/- 0.01 s), and cough volume acceleration (5.5 +/- 1.3 versus 27.8 +/- 3.9 mL/s/s) were significantly i mpaired in severe aspirators as compared with nonaspirators. Aspirating pat ients had more severe strokes than nonaspirators (mean Canadian Neurologica l Scale score 7.7 +/- 0.7 versus 9.8 +/- 0.3). Multivariate logistic regres sion found only expulsive phase rise time values during cough correlated wi th aspiration status. Conclusion: Objective analysis of cough may provide a noninvasive way to identify the aspiration risk of stroke patients.