Silent saliva aspiration in Parkinson's disease

Silent laryngeal penetration and silent aspiration (SLP/SA) are common manifestations in Parkinson's disease (PD) patients and are frequently associated with dysphagia. However, little is known about saliva aspiration in this population.

We investigated the frequency and characteristics of saliva SLP/SA in PD patients with daily drooling (Group A) and in individuals without PD or daily drooling (Group B).

Both groups were evaluated by fiberoptic endoscopic evaluation of swallowing (FEES) after dyeing the oral cavity with blue dye. The oropharynx was assessed for the presence of the stasis of saliva, and sensitivity was tested by direct tactile stimuli.

PD patients (n = 28) and controls (n = 18) were evaluated. We observed silent aspiration of saliva in 10.7% and silent laryngeal penetration of saliva near the vocal folds in 28.6% of Group A; however, none of these events was observed in Group B. Sensitivity in the epiglottis and posterior wall of the hypopharynx was decreased in 89.2% of Group A and in 33.3% of Group B, whereas in the aryepiglottic folds and interarytenoid area, a decrease in sensitivity was observed in 92.8% and in 44.4% of Groups A and B, respectively.

Silent aspiration and laryngeal penetration of saliva are common features in PD patients with daily drooling. The presence of hypoesthesia of the laryngeal structures and the lack of protective reflexes in such patients may play a major role in the mechanisms of SLP/SA.