Tongue Strength and Endurance in Patients with Parkinson’s Disease: Association with Swallowing, Oral Phase Efficiency, Meal, Diet Type and Malnutrition Risk

Tongue motor impairment has been documented and associated with the severity of dysphagia in patients with Parkinson's disease (PD). Yet, no study investigates the relation between tongue measures and oral phase, swallowing performance during meal, and nutrition in this population. The study aims to measure maximum isometric tongue pressure (MIP) and endurance in patients with PD and to study their association with swallowing- and meal-related safety and efficiency, oral phase efficiency, diet type, and malnutrition risk. Thirty-tree patients with PD were enrolled. Tongue MIP and endurance were measured using the Iowa Oral Performance Instrument. Patients underwent a Fiberoptic Endoscopic Evaluation of Swallowing (FEES). Meal safety and efficiency were evaluated with the Mealtime Assessment Scale (MAS), while the Test of Masticating and Swallowing Solids (TOMASS) was used to analyze oral phase efficiency. Diet type was described according to the Functional Oral Intake Scale (FOIS) and malnutrition risk was assessed using the Mini Nutritional Assessment (MNA). The median MIP was 40 kPa, while the median tongue endurance was 14 s. At univariate regression analysis, both MIP and tongue endurance were significantly (p < 0.05) associated with TOMASS, MAS, FOIS, and MNA, while a significant association with FEES was only found between MIP and the severity of residue in the pyriform sinus with liquids. In conclusion, reduced tongue strength and endurance seem to be associated with the worsening of oral phase efficiency, swallowing performance during meal, diet type and malnutrition risk, but not with pharyngeal signs of dysphagia in PD.