Objective
To identify the usefulness of laryngeal reflex cough test (LRCT) as screening test for aspiration, especially silent aspiration, in stroke patients with dysphagia. Method: Gag reflex (GR), 3-oz water swallow test (WST) and LRCT were performed in 70 stroke patients with dysphagia and their results were compared with those of videofluoroscopic swallowing study (VFSS). Laryngeal reflex cough was induced with the nebulized 20% l-tartaric acid, which irritates the mucosa of laryngeal vestibule. Diagnostic values such as sensitivity, specificity, predictive values, accuracy of each test for detecting aspiration and silent aspiration shown in VFSS were evaluated. Results: 37 out of 70 patients (53%) showed subglottic aspiration or supraglottic penetration in VFSS. Sensitivity and specificity of LRCT to diagnose aspiration on VFSS were 16% and 88%, respectively. Positive and negative predictive value, and accuracy were 60%, 48%, and 50% respectively. Sensitivity and specificity of GR and WST for detecting aspiration were 46%, 73% and 43%, 82%. In 28 patients (40%), VFSS revealed aspiration without cough (silent aspiration). Sensitivity and specificity of LRCT for detecting silent aspiration were 14% and 78%, whereas those of GR and WST were 50%, 67% and 50%, 78%. By combining of all tests sensitivity for detecting aspiration and silent aspiration were 76% and 92%. Conclusion: LRCT showed inadequate sensitivity and predictive values in predicting the risk of aspiration and silent aspiration. Combining LRCT with GR and WST improved sensitivities for detection of aspiration and silent aspiration. (J Korean Acad Rehab Med 2007; 31: 298-304)
