Original article| Volume 93, ISSUE 11, P1982-1986, November 2012

Simplified Cough Test for Screening Silent Aspiration


      Sato M, Tohara H, Iida T, Wada S, Inoue M, Ueda K. Simplified cough test for screening silent aspiration.


      To simplify the cough test to screen silent aspiration without sacrificing accuracy.


      Criterion standard.


      University dental hospital.


      Consecutive patients (N=141; 92 men, 49 women; mean age 71±14y, range 23–94y) who had complained of some dysphagic symptoms between June 2008 and February 2010.


      All patients were administrated a simplified cough test and underwent the fiberoptic endoscopic evaluation of swallowing. Citric acid inhalation was terminated when the first cough occurred, and the time between the start of inhalation and the first cough was measured.

      Main Outcome Measures

      The time when the first cough was observed by the simplified cough test was compared with the results of the fiberoptic endoscopic evaluation of swallowing, which was used as a criterion standard.


      Receiver operating characteristic curve analysis was performed for 53 patients evaluated as having aspiration by fiberoptic endoscopic evaluation of swallowing. We found that 30 seconds or less was an appropriate cutoff value for detecting patients without silent aspiration, where the sensitivity was .92 and the specificity was .94. From the receiver operating characteristic curve analyses for all patients, 60 seconds or less was determined to be an appropriate cutoff, and the sensitivity and specificity were .81 and .65, respectively.


      The simplified cough test is a useful screening tool for silent aspiration in patients with aspiration.

      Key Words

      List of Abbreviations:

      AUC (area under the receiver operating characteristic curve), FEES (fiberoptic endoscopic evaluation of swallowing), NPV (negative predictive value), RAR (rapidly adapting receptor), ROC (receiver operating characteristic), SCT (simplified cough test)
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        • Gordon C.
        • Hewer R.L.
        • Wade D.T.
        Dysphagia in acute stroke.
        BMJ. 1987; 295: 411-414
        • Depippo K.L.
        • Holas M.A.
        • Reding M.J.
        Validation of the 3-oz water swallow test for aspiration following stroke.
        Arch Neurol. 1992; 49: 1259-1261
        • Smithard D.G.
        • O'Neill P.A.
        • Park C.
        • et al.
        Can bedside assessment reliably exclude aspiration following acute stroke?.
        Age Aging. 1988; 27: 99-106
        • Gottlieb D.
        • Kipnis M.
        • Sister E.
        • Vardi Y.
        • Brill S.
        Validation of the 50ml drinking test for evaluation of post-stroke dysphagia.
        Disabil Rehabil. 1996; 18: 529-532
        • Tohara H.
        • Saitoh E.
        • Mays K.A.
        • Kuhlemeier K.
        • Palmer J.B.
        Three tests for predicting aspiration without videofluorography.
        Dysphagia. 2003; 18: 126-134
        • Ramsey J.C.
        • Smithard D.G.
        • Kalra L.
        Early assessments of dysphagia and aspiration risk in acute stroke patients.
        Stroke. 2003; 34: 1252-1257
        • Lim H.B.
        • Lieu P.K.
        • Phua S.Y.
        • et al.
        Accuracy of bedside clinical methods compared with fiberoptic endoscopic examination of swallowing (FEES) in determining the risk of aspiration in acute stroke patients.
        Dysphagia. 2001; 16: 1-6
        • Wakasugi Y.
        • Tohara H.
        • Hattori F.
        • et al.
        Screening test for silent aspiration at the bedside.
        Dysphagia. 2008; 23: 364-370
        • Wakasugi Y.
        • Tohara H.
        • Nakane A.
        • et al.
        Study of usefulness of the cough test as to screening for silent aspiration.
        Jpn J Dysphagia Rehabil. 2008; 2: 109-117
        • Sekizawa K.
        • Ujiie Y.
        • Itabashi S.
        • Sasaki H.
        Lack of cough reflex in aspiration pneumonia.
        Lancet. 1990; 335: 1228-1229
        • Teramoto S.
        • Fukuchi Y.
        Detection of aspiration and swallowing disorder in older stroke patients: simple swallowing provocation test versus water swallowing test.
        Arch Phys Med Rehabil. 2000; 81: 1517-1519
        • Wu M.C.
        • Chang Y.C.
        • Wang T.G.
        • Lin L.C.
        Evaluating swallowing dysfunction using a 100-ml water swallowing test.
        Dysphagia. 2004; 19: 43-47
        • Zaidi N.H.
        • Smith N.H.
        • King S.C.
        • Park C.
        • O'Neill P.A.
        • Connolly M.J.
        Oxygen desaturation on swallowing as a potential marker of aspiration in acute stroke.
        Age Aging. 1995; 24: 267-270
        • Collins M.J.
        • Bakheit A.M.O.
        Does pulse oximetry reliably detect aspiration in dysphagic stroke patients?.
        Stroke. 1997; 28: 1773-1775
        • Sherman B.
        • Nisenboum J.M.
        • Jesberqer B.L.
        • Morrow C.A.
        • Jesberqer J.A.
        Assessment of dysphagia with the use of pulse oximetry.
        Dysphagia. 1999; 14: 152-156
        • Sellars C.
        • Dunnet C.
        • Carter R.
        A preliminary comparison of videofluoroscopy of swallow and pulse oximetry in the identification of aspiration in dysphagic patients.
        Dysphagia. 1998; 13: 82-86
        • Wang T.G.
        • Chang Y.C.
        • Chen S.Y.
        • Hsiao T.Y.
        Pulse oximetry does not reliably detect aspiration on videofluoroscopic swallowing study.
        Arch Phys Med Rehabil. 2005; 86: 730-734
        • Leder S.B.
        Use of arterial oxygen saturation, heart rate, and blood pressure as indirect objective physiologic markers to predict aspiration.
        Dysphagia. 2000; 15: 201-205
        • Zenner P.M.
        • Losinski D.S.
        • Mills R.H.
        Using cervical auscultation in the clinical dysphagia examination in long-term care.
        Dysphagia. 1995; 10: 27-31
        • Shaw J.L.
        • Sharpe S.
        • Dyson S.E.
        • et al.
        Bronchial auscultation: an effective adjunct to speech and language therapy bedside assessment when detecting dysphagia and aspiration?.
        Dysphagia. 2004; 19: 211-218
        • Logemann J.A.
        Evaluation and treatment of swallowing disorders.
        2nd ed. Pro-Ed, Austin1998
        • Le Brun P.P.
        • de Boer A.H.
        • Heijerman A.H.
        • Frijlink H.A.
        A review of the technical aspects of drug nebulization.
        Pharm World Sci. 2000; 22: 75-81
        • Sinbo T.
        Ultrasonic nebulizer and jet nebulizer Q&A.
        Jpn J Nurs. 2004; 24: 78-84
        • Ogoshi T.
        • Iwata A.
        Distribution of aerosol-particle in human respiratory tract.
        J Med Soc Toho Univ. 1987; 34: 207-214
        • Tanaka T.
        • Baba T.
        • Saito E.
        • Okui Y.
        • Tohara H.
        • Mizuno M.
        An investigation of screening test of silent aspiration by cough test: the decision of the concentration of citric acid.
        Jpn J Dysphagia Rehabil. 2000; 4: 163
        • Widdicombe J.G.
        Neurophysiology of the cough reflex.
        Eur Respir J. 1995; 8: 1193-1202
        • Karlsson J.A.
        Afferent neural pathways in cough and reflex bronchoconstriction.
        J Appl Physiol. 1988; 65: 1007-1023
        • Widdicombe J.G.
        Functional morphology and physiology of pulmonary rapidly adapting receptors.
        Anat Rec Part A. 2003; 270A: 2-10
        • Widdicombe J.G.
        Neuroregulation of cough: implication for drug therapy.
        Curr Opin Pharmacol. 2002; 2: 256-263
        • Millqvist E.
        • Bende M.
        Capsaicin cough sensitivity is decreased in smokers.
        Respir Med. 2001; 95: 19-21