Detection of swallowing disorders with a multiple-channel surface electromyography sensor sheet.

Background/purpose: A sensor sheet comprising multiple electromyography electrodes that can be used to measure a series of multiple muscle activities related to swallowing was recently developed. In this study, we aimed to evaluate its utility in detecting swallowing disorders with a new method for the identification of muscle activity. Materials and methods: All participants were evaluated by using the repetitive saliva swallowing test and modified water swallowing test and were classified accordingly into participants with (n = 21; mean age, 81.6 [standard deviation, 10.1] years) and those without (n = 41; mean age, 70.0 [8.4] years) dysphagia. The sheet contains four pairs of electrodes, and surface electromyography (sEMG) was performed on the suprahyoid (position A: upper front of the suprahyoid muscles; position B: bottom rear of the suprahyoid muscles) and infrahyoid (position C: above the infrahyoid muscles; position D: beneath the infrahyoid muscles) muscles while the participants swallowed liquid, thickened water, paste, and jelly. The sEMG findings, including the duration of swallowing waveforms and the delay in swallowing onset from position A to positions B, C, and D, were compared between the groups. Results: The duration of muscle activity differed between the groups in the infrahyoid muscles when jelly (Mann-Whitney U test; position C, P = 0.007 and position D, P = 0.018) and thickened water (position C, P = 0.033) were swallowed. Conclusion: Our study demonstrates the utility of a novel sensor sheet developed for detecting swallowing disorders by using visual methods for identification of muscle activity.

Investigation of variation factors in EMG measurement of swallowing: instruction can improve EMG reproducibility.

Variability in swallowing electromyography (EMG) has been reported to occur due to individual differences, even in studies with appropriate control of factors affecting EMG such as food type, properties, and posture. The increased variability broadens the confidence intervals of measures obtained from EMG, such as time and amplitude, and makes it difficult to detect differences in muscle activity. This makes it impossible to detect slight changes in swallowing function at an early stage, which is required for clinical examination. In this study, we focused on the tipper type and dipper type of oral swallows, which differ in the timing of muscle activity. The frequency of occurrence of both types varies between participants, and both types could occur in the same participant. In this study, we measured swallowing EMG wherein participants were instructed to swallow with a tipper and a dipper. The results showed that there was a significant difference in the between-participant duration between these two types of swallows. Within-participant variability was significantly lower in the tipper-dipper instruction condition compared to the baseline condition, which assumed a mixture of tipper-dipper swallowing. These results demonstrate that instructions on swallowing method are effective in improving the reproducibility of EMG.

Detection of swallowing disorders using a multiple channel surface electromyography sheet: A preliminary study.

BACKGROUND/PURPOSE: We invented a sensor sheet with multiple electromyogram electrodes, which can be easily attached to the front of the neck, to evaluate surface electromyograms (sEMG) during swallowing function. In this paper, we evaluated sEMG in healthy volunteers and dysphagia patients using the sensor sheet and discussed its potential to evaluate swallowing function. MATERIALS AND METHODS: Ten healthy volunteers (age, 29.5 ±â€¯3.9 years) and 18 clinically diagnosed dysphagia patients (age, 67.8 ±â€¯12.1 years) were included. The sensor sheet had four pairs of electrodes, and sEMG at the suprahyoid muscles (positions A and B) and the infrahyoid muscles (positions C and D) were recorded while swallowing water, thickened water, yogurt, and jelly; sEMG findings were compared between these positions. RESULTS: Significant differences in the duration of muscle activity was observed when swallowing yogurt at position D and when swallowing jelly, thickened water, and water at position B (Mann-Whitney U test, p < 0.05). In healthy volunteers, muscle activation typically began from positions A or B to position D, whereas in dysphagia patients, it sometimes began from position D. CONCLUSION: There were significant differences in duration and sequence patterns of four sEMG activities between healthy young volunteers and dysphagia patients in the assessment using the sensor sheet, although some technical and scientific problems remained unresolved. These results indicate that swallowing function could be evaluated using the sensor sheet.

Effects of age and gender on swallowing activity assessed by electromyography and laryngeal elevation.

BACKGROUND: Quantitative assessment of swallowing function is necessary to prevent swallowing impairment due to ageing. Though surface electromyography (EMG) has been widely used to measure swallowing activity, the relationship between EMG results and swallowing function is unclear. OBJECTIVE: This study examined the relationship between the temporal characteristics of muscle activity and laryngeal elevation (LE) during swallowing. METHODS: This study analysed 60 healthy volunteers in two age groups (young, between 20 and 38 years; old, between 65 and 75 years), each containing the same number of male and female participants. Surface EMG signals were recorded from the suprahyoid and infrahyoid muscle groups (SH-EMG and IH-EMG, respectively). LE was measured using an array of pressure sensors. The participants swallowed 3 mL of water under three swallowing speed conditions: fast, normal and slow swallowing. The EMG duration, EMG time intervals before and after the onset of LE (pre-LE and post-LE intervals, respectively), and the LE velocity were analysed. RESULTS: Both EMG duration and the post-LE interval of IH-EMG were significantly longer in the older group. As for the gender effect, the pre-LE interval of SH-EMG was significantly longer and the LE velocity was significantly higher in men than in women. Furthermore, there was a negative correlation between pre-LE interval and LE velocity in the fast swallowing condition. CONCLUSION: Though ageing slightly prolonged the muscle activity time, gender influenced swallowing activity in a more complex manner. Therefore, it is important to take gender into account when examining swallowing function with increasing age.