Validation of Assessment of Medication Swallowability by Surface Electromyography Measurement: Evaluating the Effect of Capsule Size on Medication Adherence

A decrease in adherence leads to a reduced treatment effect, and improving adherence in treatment is a significant issue worldwide. Medication non-adherence is caused by a variety of factors, and difficulty in swallowing medications has also been suggested to contribute to non-adherence. Therefore, when developing a medicine, it is important to strive to make it easy to swallow, and it is equally important to correctly evaluate the ease of swallowing a medicine. Subjective questionnaire evaluations, which are important evaluation systems, are mainly used to evaluate the ease of swallowing medicines. However, it is widely known that various biases (common method biases (CMB)) occur in questionnaire-based assessment methods, and it is difficult to eliminate them completely. In this study, we investigated a highly objective method for evaluating the ease of swallowing medicines using an instrument. Surface electromyography measurement of swallowing-related muscles, which is one of the methods for evaluating swallowing ability and the feeling of swallowing using an instrument, is a minimally invasive and simple method. In this study, we evaluated the ease of swallowing capsules in healthy adults and assessed whether the electromyographic activity of swallowing-related muscles can be used to evaluate the ease of swallowing a medicine. The results showed a correlation between the amount of muscle activity (area value) when swallowing a capsule and capsule size. In addition, it was shown that there was a positive correlation between the questionnaire results and muscle activity. These results indicate that assessing the surface muscle activity of swallowing-related muscles is a useful method for evaluating medication adherence.