Screening test for silent aspiration at the bedside.

Many screening tests for dysphagia can be given at bedside. However, they cannot accurately screen for silent aspiration (SA). We studied the usefulness of a cough test to screen for SA and combined it with the modified water swallowing test (MWST) to make an accurate screening system. Patients suspected of dysphagia (N = 204) were administered a cough test and underwent videofluorography (VF) or videoendoscopy (VE). Sensitivity of the cough test for detection of SA was 0.87 with specificity of 0.89. Of these 204 patients, 107 were also administered the MWST. Fifty-five were evaluated as normal by the screening system, 49 of whom were evaluated as normal by VF or VE. Sixteen were evaluated as "SA suspected" by the screening system; seven of them were normal, and seven were evaluated as having SA by VF or VE. Nineteen were evaluated as aspirating with cough, 14 of whom had aspiration with cough as shown by VF or VE. Seventeen were evaluated as having SA, 15 of whom had SA shown by VF or VE. The cough test was useful in screening for SA. Moreover, a screening system that included MWST and a cough test could accurately distinguish between the healthy who were safe in swallowing and SA patients who were unsafe.