Supplementary Material for: Comparison of Swallowing Dysfunction, Endurance, and Dysphagia Symptom Severity in Early-Stage Alzheimer’s Disease and Age-Matched Controls

Aim: The aim of this study is to compare swallowing dysfunction, swallowing endurance, and dysphagia symptom severity in early-stage Alzheimer’s disease (AD) and age-matched healthy controls (HCs). Methods: The case-control study included twenty-five individuals diagnosed with AD and fifteen age-matched elderly participants. Demographic data, including body mass index (BMI), disease history, comorbidities, and food habits, were obtained from first-degree relatives or patient records. Swallowing dysfunction was assessed using standardized dysphagia tests, including the 10-mL and 100-mL water swallowing tests. Swallowing endurance was assessed using the Repetitive Saliva Swallowing Test (RSST), and dysphagia symptom severity was evaluated with the Eating Assessment Tool-10 (EAT-10). Results: The duration of the 10 ml water swallow test was significantly longer in individuals with AD compared to HCs [4.1 (3.1-5.5), � confidence interval (CI) of 3.2 to 5.5 versus 3 (2.4-3.5), � CI of 2.4 to 3.5; effect size = 0.325, p = 0.019]. The groups were similar in terms of EAT-10 score (p = 0.400), 100-ml water swallowing test duration (p = 0.197) and RSST (p = 0.319) results. EAT-10 score was correlated with disease duration (r = 0.451, p = 0.031) and total number of snacks (r = -0.404, p = 0.045) in AD group. Additionally, the 100-ml water swallowing test duration was correlated with BMI (r = -0.559, p = 0.004) in individuals with AD. Conclusions: It has been determined that swallowing difficulties in individuals with AD are associated with disease duration, BMI and snack consumption. Swallowing dysfunction is common in individuals with early-stage AD and they exhibit a longer duration in the 10 ml water swallowing test compared to HCs. This test may be an indicator of dysphagia. Early screening for dysphagia in these individuals is essential to prevent potential complications and enable timely interventions.