Electrical stimulation (e-stim) has been studied extensively as a potential treatment for swallowing impairments, known as dysphagia. Dysphagia can significantly reduce quality of life, increase the risk of medical complications and mortality, and pose a substantial cost to healthcare systems. Therefore, the interest in new avenues for dysphagia rehabilitation, such as e-stim, is growing.
E-stim for the treatment of swallowing impairments is among the most studied swallowing interventions in the published literature, yet many unanswered questions about its efficacy remain. This review aims to provide an overview of the current knowledge on the topic, discussing the values and limitations of the published literature on e-stim for swallowing.
Swallowing is a complex neuromuscular task, requiring rapid and precise coordination of numerous cranial nerves and muscle pairs. Impairments of swallowing have the potential to confound and even precede medical complications, and reduce quality of life in patients. This has intensified the call for successful, restorative management options for dysphagia.
Since the late 1980s, there has been an increasing amount of discussion regarding the effects of e-stim in individuals with dysphagia. Many of the early claims of success were not validated with scientific research and consequently, offer no more than testimonials and anecdotal reports. However, the U.S. Food and Drug Administration cleared VitalStim Therapy to market external e-stim for dysphagia in 2002, and since then, numerous scientific reports have been dedicated to understanding its effect on normal and disordered swallowing over both short- and long-term periods.
Studies of the effects of e-stim on swallowing can be separated by the length of the study (immediate vs. long-term) and the population being studied (healthy vs. patient population). Immediate-effects e-stim studies aim to answer questions about changes to physiology with muscle stimulation, while long-term studies in healthy and unhealthy populations answer questions about possible system changes that have rehabilitative potential, carry-over effects, and the duration of any observed therapeutic benefit.
In conclusion, while e-stim presents a promising avenue for the treatment of dysphagia, more research is needed to fully understand its efficacy and the best methods of application. Clinicians must take an individualized approach when considering e-stim as a treatment option, always keeping the clinical goal for the patient in mind.