Comparison of Submental Surface Electromyography during Dry Swallow between Irradiated Head and Neck Cancer Survivors and Normal Individuals.

Introduction: This study compared the submental surface electromyography (sEMG) duration and amplitude during dry swallowing between irradiated head and neck cancer (HNC) survivors and age-matched normal individuals. Further, the relationship between submental and infrahyoid sEMG in the irradiated HNC group was explored.

Method: Forty participants (20 HNC survivors and 20 age-matched normal individuals) participated in this study. The HNC survivors had completed organ preservation cancer treatment (at least 1-month post-treatment). They were on a complete oral diet without enteral supplementation (FOIS score> 4). Submental and infrahyoid sEMG activity was calculated for three trials of saliva swallow for each participant using sEMG. The duration and amplitude parameters considered were: onset duration - duration from the onset of swallowing to the maximum amplitude, offset duration - duration from the maximum amplitude to the end of the swallowing activity, total duration, and maximum amplitude.

Results: The study found that irradiated HNC survivors exhibited prolonged temporal measures, particularly in the offset duration, which suggested a delayed descent of the hyolaryngeal complex during swallowing. Additionally, the HNC group showed a positive correlation between submental and infrahyoid sEMG. Furthermore, it was observed that the rate of increase in the duration of submental sEMG during subsequent swallowing was greater in HNC survivors which could be due to reduced salivation.

Conclusion: Compared to age-matched normal individuals, irradiated HNC survivors manifest alterations in the submental muscle activities during dry swallowing as measured using sEMG. The temporal and amplitude changes are likely to have arisen as a consequence of postradiation changes.