Association between maximum tongue pressure and swallowing safety and efficacy in amyotrophic lateral sclerosis

Background: Oropharyngeal dysphagia (OD) is common in amyotrophic lateral sclerosis (ALS), leading to a reduction of swallowing safety and efficacy. The tongue has an important role in swallowing function for oral processing and bolus propulsion through the pharynx. The study aims to analyze the association between instrumental findings of OD and tongue pressure. Methods: Patients with ALS referred for fiberoptic endoscopic evaluation of swallowing (FEES) were recruited. FEES was conducted to test swallowing function with liquid (5, 10, and 20 ml), semisolid (5, 10, and 20 ml), and solid. FEES recordings were assessed for swallowing safety, using the penetration-aspiration scale (PAS), and for swallowing efficacy, using the Yale Pharyngeal Residue Severity Rating Scale (YPRSRS). PAS scores >2 were suggestive of penetration, PAS scores >5 of aspiration, and YPRSRS scores >2 of residue. Maximum tongue pressure (MTP) and tongue endurance were measured using the Iowa Oral Performance Instrument. Tongue pressure measurements were compared between patients with and without penetration, aspiration, or residue. Key results: Fifty-five patients with ALS were included. Mean MTP was 29.7 kPa, and median tongue endurance was 10 seconds. Patients with residue in the pyriform sinus had a significantly lower MTP than patients without residue in the pyriform sinus with semisolids 10 ml (P =.011) and 20 ml (P =.032). Patients with a tongue endurance <10 seconds exhibited higher frequency of penetration with liquids 5 ml (P =.046), liquids 10 ml (P =.015), and solids (P =.22). Conclusion and inferences: In patients with ALS, MTP is significantly associated with an impairment of swallowing efficacy and tongue endurance was significantly associated with an impairment of swallowing safety.