Physiologic Model of Oropharyngeal Swallowing Revisited

Abstract

The purposes of this investigation were to determine whether the temporal onsets of swallow events segment into oral and pharyngeal phases, to test the interdependence of temporal onsets of swallow events, and to determine the influence of age on total swallow duration. The onsets of swallowing and respiratory measures were studied in 76 healthy normal individuals. Confirmatory factor analysis revealed a 2-factor solution but did not support the hypothesized 2-phase structure (ie, oral and pharyngeal). Two of the onsets, apnea onset and apnea offset, formed a single factor that explained 12.6% of the variation among the 11 onset times. The other 9 onsets formed a second factor that explained 66.4% of the variation. Age accounted for modest variation in total swallow duration. The two factors, oropharyngeal and respiratory, explained 79% of the variation among the 11 onset times. This finding speaks to the overlap between the initiation of oral and pharyngeal components of swallowing in adults and highlights the artificiality of separating the swallowing continuum into isolated phases.