Laryngeal adductor reflex and pharyngeal squeeze as predictors of laryngeal penetration and aspiration.

Abstract

The contribution of laryngopharyngeal (LP) sensory deficits to the outcome of swallowing and the relationship between sensory and motor deficits in the laryngopharynx is unclear. The study purpose is to determine if patients with LP sensory and motor deficits are at increased risk for laryngeal penetration and aspiration during swallowing, and to determine the relationship between pharyngeal motor weakness and LP sensory deficits. Endoscopic evaluation of swallowing with sensory testing was performed on 122 dysphagic patients who were prospectively divided into two groups. The control group was 76 patients with normal sensitivity, determined by an intact laryngeal adductor reflex (LAR) on air pulse stimulation of the mucosa innervated by the superior laryngeal nerve. The study group was 46 patients with severe sensory deficits, determined by an absent LAR. Each group was given puree followed by thin liquid, noting presence or absence of laryngeal penetration and aspiration. Pharyngeal muscle strength was assessed by noting presence or absence of pharyngeal contraction during voluntary adduction of the vocal folds (pharyngeal squeeze). In control subjects, with purees, 6 of 76 (7.90%) penetrated and 3 of 76 (3.94%) aspirated; with thins, 26 of 76 (34.2%) penetrated and 13 of 76 (17.1%) aspirated. In the absent LAR group, with purees, 39 of 46 (84.8%) penetrated and 32 and 46 (69.6%) aspirated; with thins, 46 of 46 (100%) penetrated and 43 of 46 (93.5%) aspirated. For both consistencies, the differences in prevalence of penetration and aspiration between groups was significant (P <.0001, chi2). In control subjects, pharyngeal squeeze was impaired in 17 of 76 (22.4%), with penetration of puree in 6 of 17 (35.3%) and aspiration in 3 of 17 (17.6%). In the absent LAR group, squeeze was impaired in 41 of 46 (89.1%), with penetration of puree in 39 of 41 (95.1%) and aspiration in 32 of 41 (78.0%). The difference in the prevalence of pharyngeal weakness between groups was significant (P <.0001). The difference in the prevalence of penetration and aspiration was higher in the absent LAR/impaired contraction cohort than in the normal sensation/impaired contraction cohort (P <.0001). Absence of the LAR and impaired pharyngeal squeeze puts patients with dysphagia at high risk for laryngeal penetration and aspiration compared with patients with an intact LAR and intact pharyngeal squeeze. There is a strong association between motor and sensory deficits in the laryngopharynx.