Can an oral mechanism examination contribute to the assessment of odds of aspiration?

Use of an oral mechanism examination is ubiquitous and long-standing despite a paucity of research supporting its clinical utility in dysphagia diagnostics. The purpose of this study was to investigate whether components of an oral mechanism examination, i.e., binary judgments (complete/incomplete) of labial closure, lingual range of motion, and facial symmetry, were associated with increased odds of aspiration as confirmed by subsequent instrumental testing. Study design was a single-group consecutively referred case series with a single judge. A total of 4,102 consecutive inpatients from a large, urban, tertiary-care teaching hospital were accrued, with 3,919 meeting the inclusion criterion of adequate cognitive ability to participate in an oral mechanism examination followed immediately by a fiberoptic endoscopic evaluation of swallowing. Stepwise multiple logistic regression analysis indicated that participants with incomplete lingual range of motion had an odds of aspiration that was 2.72 times the odds of aspiration of those with complete lingual range of motion (95% confidence interval [CI] = 1.96-3.79, p < 0.0001), and incomplete lingual range of motion was an independent risk factor for aspiration regardless of labial closure and facial symmetry. Participants with incomplete facial symmetry had an odds of aspiration that was 0.76 times the odds of aspiration of those with complete facial symmetry (95% CI = 0.61-0.95, p = 0.017). Isolated incomplete labial closure did not affect the odds of aspiration (p > 0.05). New and clinically relevant information was found for lingual range of motion and facial symmetry, i.e., when incomplete, the clinician should be alerted to potential increased odds of aspiration during subsequent instrumental dysphagia testing.