Supportive effect of interferential current stimulation on susceptibility of swallowing in guinea pigs

Abstract

Sensory-motor control of the pharyngeal swallow requires sensory afferent inputs from the pharynx and larynx evoked by introducing bolus into the pharynx. Patients with reduced sensitivity of the pharynx and larynx are likely to have a swallowing impairment, such as pre-swallow aspiration due to delayed swallow triggering. Interferential current stimulation applied to the neck is thought to improve the swallowing function of dysphagic patients, although the mechanism underlying the facilitatory effect of such stimulation remains unknown. In the present study, we examined the changes in the elicitability of swallowing due to the stimulation and the responses of the swallowing-related neurons in the nucleus tractus solitarius and in the area adjacent to the stimulation in decerebrate and paralyzed guinea pigs. The swallowing delay time was shortened by the stimulation, whereas the facilitatory effect of eliciting swallowing was attenuated by kainic acid injection into the nucleus tractus solitarius. Approximately half of the swallowing-related neurons responded to the stimulation. These data suggest that the interferential current stimulation applied to the neck could enhance the sensory afferent pathway of the pharynx and larynx, subserving excitatory inputs to the neurons of the swallowing pattern generator, thereby facilitating the swallowing reflex.

Cervical Interferential Current Transcutaneous Electrical Sensory Stimulation for Patients with Dysphagia and Dementia in Nursing Homes

“…[3][4][5][6][7] However, as TENS cannot stimulate structures situated deep in the body, an interferential current has been developed to overcome this disadvantage; 8 interference between electricity of two different frequencies generates a new interferential current inside the human body that can affect deeply situated sensory nerves. 9 The use of interferential currents to facilitate swallowing training has yielded the following findings concerning interferential currents: (i) in decerebrate and paralyzed animals, the reduction of the latency time in the elicitation of the swallowing reflex and the excitation of swallowingrelated neurons in the brain stem; 10 (ii) in healthy human volunteers, the reduction of the swallowing threshold; 11,12 and (iii) in patients with chronic, pharyngeal-stage dysphagia and mini-mental state exam (MMSE) scores of 21 or more, the improvement of the swallowing reflex. 13,14 Furthermore, interferential current transcutaneous electrical sensory stimulation (IFC-TESS) improved cough latency times and increased oral calorie intake in patients with dysphagia and dementia in an acute or recovery medical care facility.…”

Influences of GABAergic Inhibition in the Dorsal Medulla on Contralateral Swallowing Neurons in Rats

“…Thus, in accordance with previous publications our study supports the notion that the neuronal networks of swallowing interneurons are widely distributed in the NTS and the RF, which in turn, directly or indirectly control the oropharyngeal motor pattern of swallowing. 1,3,25,26,40…”

Interferential Current Stimulation for Swallowing Disorders in Chronic Obstructive Pulmonary Disease: A Preliminary Study

“…In basic animal research with guinea pigs, IFC-TESS shortened the swallow delay time, suggesting that it could enhance the pharyngolaryngeal sensory afferent pathway, subserving excitatory inputs to the swallowing pattern generator, and hence facilitate the swallowing reflex. 6) In clinical studies, IFC-TESS was reportedly effective in dysphagic patients with dementia, 7) aspiration pneumonia, and other conditions. 8) However, its efficacy in COPD patients is unknown.…”