Vocal Tasks to Detect a Decline in Swallowing Function among the Community-Dwelling Older Adults: Acoustic Characteristics of Laryngeal Diadochokinesis (LDDK).

INTRODUCTION: Age-related decline in laryngeal function can lead to dysphagia and dysphonia. While both swallowing and phonation involve laryngeal closure, their mechanisms and control differ. Laryngeal diadochokinesis (LDDK) provides a simple insight into the neuromotor function of the larynx. We hypothesized that the acoustic characteristics of laryngeal diadochokinesis (LDDK) are associated with performance on the 100-mL water swallowing test. We aimed at acoustically describing the vocal characteristics of LDDK in healthy older adults and investigating its relationship with swallowing function. METHOD: This retrospective study analyzed existing data from a previous study conducted by Katsumata (2021). The participants were 70 healthy community-dwelling older adults who were independent in daily living. Swallowing function was assessed using the 100-mL water swallowing test, classifying participants into two groups: one with declined swallowing function (DSF) and the other with good swallowing function (GSF). Vocal function was evaluated through acoustic analysis of recorded voice samples obtained from the LDDK task. Three parameters (i.e., LDDK repetition rate, voicing duration, and percentage of signal fusion) were measured. RESULTS: The age of the DSF group was significantly older than the GSF group. LDDK measures demonstrated high intra- and inter-examiner reliability. male participants showed significantly longer voicing duration and higher percentage of signal fusion than females. All measured LDDK parameters revealed statistically significant differences between the two groups: slower repetition rate, longer voicing duration, and higher percentage of signal fusion in DSF than in GSF. Voicing duration demonstrated moderate sensitivity for detecting abnormal findings in the 100-mL water swallowing test. CONCLUSIONS: The results of this study suggest that LDDK acoustic parameters are associated with age-related laryngeal changes and are related to the decline in vocal and swallowing functions in community-dwelling older adults.