Abstract
Swallowing disorders are a common complaint among the elderly. Recently, surface electrical stimulation applied to the neck region has received increased attention as a new modality to treat pharyngeal dysphagia. Previous reports used pulsed current at a frequency range of 1-120 Hz. Kilohertz-frequency alternating currents (ACs) have not been tested for treating dysphagia. Therefore, we evaluated the effects of interferential currents (IFCs), the most popular modality of amplitude-modulated kilohertz-frequency ACs in clinical practice, on the swallowing reflex in healthy subjects. We found that IFC stimulation at the sensory threshold with 50-Hz modulation significantly increased the number of swallows without any discomfort, but pure AC stimulation at the carrier frequency did not have a significant effect. There was no statistically significant difference in the time course of the number of swallows among 1,000-, 2,000-, 4,000-, and 6,000-Hz carrier frequencies. The number of swallows remained increased during the 15-min IFC stimulation, suggesting that IFC stimulation facilitates the swallowing reflex without adaptation, at least during this stimulation period. We suggest that an IFC stimulation or a low-frequency, modulated kilohertz AC stimulation, which would be more comfortable than pulsed currents, is an alternative stimulation mode for treating pharyngeal dysphagia.
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Acknowledgments
The authors thank Prof. Y. Muraoka and Dr. T. Daimon, Department of Mathematics, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan, for their valuable comments on statistical methods.
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Furuta, T., Takemura, M., Tsujita, J. et al. Interferential Electric Stimulation Applied to the Neck Increases Swallowing Frequency. Dysphagia 27, 94–100 (2012). https://doi.org/10.1007/s00455-011-9344-2
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DOI: https://doi.org/10.1007/s00455-011-9344-2