Intra- and Inter-day Reliability and the Group Differences of Acoustic Analysis of Sequential Oral Sounds in the Initial Phase among Dentate and Edentulous Older Adults

The ability to assess ingestion, mastication, and swallowing sequentially is critical for evaluating oral function in older adults. While acoustic analysis of chewing sounds has shown possibility in younger populations, its reliability and applicability in older dentate and edentulous individuals remain unclear. The current study aimed: 1. To examine the intra- and inter-day reliability of chewing sound measurements in older adults: 2. To confirm that the chewing sounds reflect the hypothesized differences in masticatory function resulting from distinct oral environments between dentate and edentulous older adult groups, group differences have been assessed by comparing chewing sounds between dentate and denture-wearing edentulous older adults. Twenty-eight older adults were recruited based on their oral status: 14 dentate individuals with natural teeth (D group) and 14 edentulous individuals wearing complete dentures (CD group). Participants chewed almonds freely while oral sounds were recorded using a high-performance sound level meter positioned at the laryngeal region. Acoustic energy during the first 10 seconds of chewing was calculated as the equivalent continuous A-weighted sound pressure level (LAeq,10s). Measurements were conducted three times in each of two sessions, one week apart. The study demonstrated that chewing sounds recorded during the initial 10 seconds of mastication exhibit excellent intra- and inter-day reliability in both groups. The group differnces between dentate and edentulous groups showed significant differences with edentulous individuals generating higher LAeq,10s values than dentate participants. These findings support the feasibility of acoustic analysis as a sequential, non-invasive tool for evaluating ingestion, mastication, and swallowing functions in older adults.