The practical utility of a device for monitoring laryngeal motion during swallowing
2Department of Rehabilitation Medicine, School of Medicine, Fujita Health University, Japan
3Department of Rehabilitation, Fujita Health University Hospital, Japan
[Introduction]
The laryngeal motion monitor (B4STM) visualizes laryngeal motion during swallowing as waveforms on a tablet, enabling automatic measurement and recording of laryngeal elevations and their detection times. This research presents two cases in which B4STM measurements during the Repetitive Saliva Swallowing Test (RSST) revealed an increase in laryngeal elevations and a reduction in detection times over follow-up. Additionally, improvements were observed in Stage Transit Duration (STD) and Dysphagia Severity Scale (DSS) scores, as assessed by videofluoroscopic swallowing studies (VFSS).
[Case 1]
An 80-year-old man with cardiogenic cerebral embolism. The initial RSST showed 2 swallows, with detection times of 6.34 and 26.98 seconds. On re-evaluation, the number of swallows increased to 3, with detection times of 5.04, 8.98, and 20.58 seconds, showing significant improvement. VFSS revealed an initial STD of 1.52 seconds for 4 ml of thin liquid, which improved to 0.61 seconds upon re-evaluation. The DSS score improved from 3 (aspiration of liquids) to 6 (mild dysphagia).
[Case 2]
An 80-year-old woman with left putaminal hemorrhage. The initial RSST showed 1 swallow with a detection time of 9.98 seconds. Upon re-evaluation, the number of swallows increased to 2, with detection times of 3.98 and 14.60 seconds. VFSS revealed an initial STD of 1.82 seconds, which improved to 1.08 seconds. The DSS score improved from 3 to 4 (occasionally aspiration).
[Conclusion]
RSST, primarily a screening tool for dysphagia based on repeated saliva swallows, provides critical insights into functional recovery by evaluating swallowing frequency and detection time. This study demonstrated that increased swallowing frequency and reduced detection times during RSST are likely associated with faster swallowing reflex times during bolus swallowing. These findings highlight the potential of B4STM as a valuable tool in assessing swallowing function and recovery.