Efficacy of interferential current transcutaneous electrical sensory stimulation through the neck skin for treating dysphagia in children with disabilities: A case series

Introduction

Dysphagia is caused by many factors, such as advancing age, neurological diseases, and head and/or neck diseases. ¹ In children, congenital or intranatal disability also causes dysphagia. In any of these cases, it is occasionally associated with aspiration pneumonia, severe nutritional and respiratory complications and even death. ¹ Although dysphagia rehabilitation, such as swallowing training and oral care, ² non-invasive brain stimulation, such as transcranial direct current stimulation,^3,4 and surgery for improving swallowing function or preventing aspiration^{5 –7} have been performed, they are not always effectual in both children and adults. In addition, medical therapy such as the use of botulinum toxin, ⁸ capsaicin, ⁹ angiotensin-converting enzyme inhibitors, ¹⁰ and the antiplatelet cilostazole ¹¹ has been developed for adult patients, but it has been challenging.

The benefits of electrical sensory stimulation treatment through the neck skin have been described in patients with dysphagia.^12,13 It was divided into two main therapies; one is neuromuscular electrical stimulation (NMES) with muscle contraction and another is transcutaneous electrical sensory stimulation (TESS), without muscle contraction. In addition, the TESS involved both pulsed current and interferential currents. Efficacy of NMES was reported in adult patients with various types of dysphagia,^{14 –17} but the efficacy of NMES in children could not be described. ¹⁸ On the contrary, the use of TESS involving a pulsed current was reported to improve swallowing in adult patients with dysphagia.^{19 –23} In addition, the beneficial effects of interferential current TESS (IFC-TESS) have been reported in adult patients recently,^24,25 but there are no reports about the beneficial effects of IFC-TESS in children thus far.

In this report, we discuss the benefits of IFC-TESS through the neck skin for dysphagia in children with disabilities because we think that IFC-TESS is also well-tolerated and usable device in children. To our knowledge, this is the first report that indicates the possible benefits of IFC-TESS treatment in children.

Case presentations

We studied the efficacy of IFC-TESS with a low-frequency massage device delivering an interferential current (Gentle Stim^®; J Careido Co., Ltd., Kanagawa, Japan) (Figure 1). Four children with disabilities of various types have performed oral care and swallowing training, but had limited effect. Therefore, they underwent IFC-TESS once a week. All patients were evaluated by videoendoscopic examination (VE) for swallowing and administered three questionnaires regarding dysphagia (A questionnaire to screen dysphagia ²⁶ (Q1) the 10-item Eating Assessment Tool ²⁷ (Q2) and the modified assessment scale of dysphagia risk for elderly persons ²⁸ (Q3) (Appendix Table 1). The characteristics and results of the four patients are summarized in Table 1.

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Figure.1.

Electrode placement. Two pairs of electrodes with different frequencies (2000 and 2050 Hz) were placed across the neck, stimulating the sensory nerves with a beat frequency of 50 Hz inside the neck.

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Table 1.

Clinical characteristics and evaluation data of patients in this study.

	Case 1	Case 2	Case 3	Case 4
Age (years)	15	5	12	4
Gender	Male	Male	Female	Male
Body weight (kg)	30	15	23	15
Disorder	HIE	Unknown	Microdeletion	HIE
PH of pneumonia	Rarely	Often	Sometimes	Never
TESS intensity (mA)	3.0	1.5	1.5	1.5
Time (minutes)	30	10	10	10
Frequency (per week)	1	1	1	1
Total treatment time (minutes)	270	90	90	110
Reversion (months)	1.5	1.5	1.5	1.5
VE findings after treatment
Accumulation of secretion	↓	↓	↓	↓
Residual bolus of food	→	↓	↓	→
Power of swallowing	→	→	↑↑	↑
A questionnaire to screen dysphagia (11)* before→after treatment
A = always or severe	3→3	8→5	9→1	5→1
B = sometimes or mild	6→6	2→4	0→8	3→6
C = never	2→2	1→2	2→2	3→4
The 10-item eating assessment tool (8)* before→after treatment
0 = never	1→2	0→1	0→0	2→2
1 = rarely	1→0	2→1	0→0	0→1
2 = sometimes	2→6	2→0	1→6	3→3
3 = often	3→0	1→4	5→0	2→1
4 = always	1→0	3→2	2→2	1→1
Total	18→12	21→21	25→20	16→14
The modified assessment scale of dysphagia risk for elderly persons (16)* before→after treatment
0 = never	3→2	0→1	0→4	3→4
1 = rarely	2→3	1→1	0→6	3→7
2 = sometimes	7→10	8→7	6→5	9→4
3 = always	4→1	7→7	10→1	1→1
Total	28→23	38→36	42→19	24→18
Side effects	None	Mild exanthema	None	None

HIE: hypoxic-ischemic encephalopathy; Microdeletion: microdeletion syndrome of chromosome; PH: past history; TESS: transcutaneous electrical sensory stimulation; VE: videoendoscopic examination of swallowing.

*

Indicates number of items evaluated in this study.

Discussion

The IFC-TESS treatment through the neck skin was thought to help improve the swallowing reflex by the activation of peripheral sensory nerves in the deep layers of the pharynx and larynx, especially superior laryngeal nerve that can trigger swallowing, without being uncomfortable. ²⁹ Recently, Maeda K et al. and Hara Y et al. studied and reported the effect of IFC-TESS, in patients at mean 84 years with dysphagia rehabilitation for over 3 weeks, and in patients at mean 84 years with dementia, respectively.^24,25 They showed that IFC-TESS improve the cough reflexes and nutritional states of patients.^24,25 In this report, we reported a possible beneficial effect of IFC-TESS on dysphagia in children with disabilities. Although our study could not be objectively analyzed for children, our cases showed reduced accumulation of secretion, reduced residual bolus, increased forcefulness of swallowing, reduced choking and coughing during swallowing, and shortened mealtimes. In addition, approximately one and a half months after the treatment, the symptoms of all patients returned to pretreatment condition. These findings indicate TESS treatment, using interferential current through the neck skin, may improve dysphagia in children with disabilities, particularly in children with the decreased swallowing reflex.

Very few adverse effects of IFC-TESS have been described, ²⁴ unlike with NMES that can cause pain or uncomfortable feelings in patients and include increased risk of aspiration and the possible risks of laryngospasm, arrhythmia, hypotension, glottic closure, and skin burns. ²¹ In our study, one of the four children developed a rash on the neck skin after IFC-TESS treatment, but it was transient and harmless. We thought IFC-TESS could be a safe and effective treatment even in children.

Conclusion

We have reported on the potential beneficial effects of IFC-TESS for dysphagia in children with disabilities. The benefits of IFC-TESS, particularly in children, needs to be further investigated by an objective study with a larger number of cases with dysphagia, which will lead to better management including dysphagia rehabilitation and medical therapy.

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